Staphylococcus: Aureus, Epidermidis, Saprophyticus (YouTube Video Transcript)

(00:00:00) Your YouTube transcript will appear here (00:00:07) what's up ninja nerds in this video (00:00:08) today we're going to be talking about (00:00:10) staphylococcus bacteria before we get (00:00:13) started if you guys really want to (00:00:14) understand this topic down in the (00:00:16) description box below we'll have a link (00:00:17) to our website on there we'll have (00:00:19) comprehensive notes we'll have (00:00:21) illustrations we have pictures before (00:00:23) the board after the board everything to (00:00:25) enable you to completely understand this (00:00:27) topic and succeed (00:00:29) please go check that out also if you (00:00:31) guys like this video you benefit from it (00:00:33) please hit that like button comment down (00:00:34) in the comment section and most (00:00:36) importantly subscribe all right let's (00:00:37) get into it all right engineers let's (00:00:39) talk about staphylococcus so (00:00:41) staphylococcus first off we should (00:00:42) actually have an understanding what (00:00:44) staph means and what the cocci means (00:00:47) okay so they're kind of like a little (00:00:48) bacterial nomenclature (00:00:50) so staff (00:00:51) means that it's kind of in a cluster (00:00:54) that's one word for it so staff (00:00:56) basically means kind of a cluster (00:00:59) of something right (00:01:01) whereas the cocci means round means (00:01:04) spherical means berry-like we're just (00:01:07) going to put kind of like spherical (00:01:09) we'll put spherical (00:01:12) so it's a cluster of spheres but here's (00:01:15) what's really interesting about (00:01:16) staphylococcus (00:01:18) all of the staphylococcus species are (00:01:20) gram (00:01:21) positive (00:01:23) go back to what color gram positive (00:01:25) bacteria stain when you do the gram (00:01:27) stain do they take retain the crystal (00:01:30) violet or not they re retain the crystal (00:01:32) violet because remember they have that (00:01:34) very thick peptidoglycan layer if they (00:01:36) stain if they actually retain the (00:01:37) crystal vial what color does that give (00:01:39) crystal violet or a purple-like (00:01:40) appearance what is it what does a (00:01:42) cluster of purple spheres look like (00:01:45) a bunch of grapes so sometimes we'll use (00:01:48) the term that staphylococcus looks like (00:01:50) a cluster of grapes (00:01:52) so staphylococcus is a cluster of (00:01:54) spheres that are gram-positive meaning (00:01:56) they look like a cluster of grapes (00:01:58) they're also non-motile meaning that (00:02:00) they don't have any flagella that enable (00:02:02) them to be able to (00:02:04) move around in different areas (00:02:06) and they're also here's where it's (00:02:07) really really important (00:02:09) they're all (00:02:10) catalase positive (00:02:12) and i am going to explain what this (00:02:14) means in just a second (00:02:17) before we do that though (00:02:19) what i want us to next understand is we (00:02:21) have staphylococcus it's a bacteria that (00:02:23) is in a cluster of spheres they're (00:02:25) gram-positive meaning that they stain (00:02:26) crystal violet or purple on gram-sitting (00:02:28) so they look like a cluster of grapes (00:02:30) they're non-motile if you also want to (00:02:32) remember another fact they're what's (00:02:33) called facultative anaerobes which means (00:02:35) that they can survive in oxygen (00:02:36) environments but they can also survive (00:02:38) in no oxygen types of environments as (00:02:40) well (00:02:41) and they're catalase positive all the (00:02:43) three types that we'll discuss (00:02:46) the next thing that i want us to discuss (00:02:47) is where would we generally find these (00:02:49) staphylococcal species like where would (00:02:51) they actually be found within the human (00:02:52) body because that's what we want to talk (00:02:53) about it's like medical microbiology how (00:02:56) is this pertinent to any kind of (00:02:57) infections or diseases (00:02:59) so (00:03:00) staphylococcus there's actually three (00:03:02) particular types that i want you guys to (00:03:03) remember the first one is staphylococcus (00:03:06) aureus so we'll put staphylococcus (00:03:09) aureus and this is a heavy kind of like (00:03:12) colonizer of the skin so it's very very (00:03:14) commonly found within the skin it's a (00:03:16) part of our natural skin flora (00:03:18) you can find it in the armpits you can (00:03:20) find it in the actual ears you can find (00:03:22) in the pharynx you can find in the (00:03:23) growing you can find it in the perineum (00:03:26) a bunch of different areas one of the (00:03:28) most important areas that you need to (00:03:30) remember for staphylococcus aureus it (00:03:32) will probably show up on your exam is (00:03:34) that it is a very very important (00:03:37) colonizer of the nairs so about 15 (00:03:41) of the healthy population have (00:03:43) colonization of staphylococcus aureus (00:03:45) within the skin of their nares (00:03:47) okay (00:03:48) the other type of staphylococcus species (00:03:50) that's also a part of our skin flora is (00:03:52) called staphylococcus epidermidis that's (00:03:55) actually a pretty easy one to remember (00:03:56) right so staphylococcus epidermidis (00:04:01) is another one and this is a part of our (00:04:03) natural skin floor actually more so than (00:04:05) staphylococcus aureus okay (00:04:08) that's the big one there so those are (00:04:10) two there the other one (00:04:12) is a very interesting one and this one (00:04:14) is called staphylococcus (00:04:17) saprophyticus you're like what the heck (00:04:20) so staphylococcus saprophyticus is the (00:04:22) other one that i want us to talk about (00:04:25) so saprophyticus you can obviously make (00:04:27) the sense of the epidermis aureus we'll (00:04:30) talk about where that terminology comes (00:04:31) in just a second but saprophyticus (00:04:36) actually kind of means that it's um it's (00:04:38) a staphylococcus that actually (00:04:40) thrives in decaying organic material (00:04:44) especially like meats so staphylococcus (00:04:46) saprophyticus can actually thrive and (00:04:48) survive and decaying types of organic (00:04:51) material like meat so imagine you take (00:04:53) and you eat a piece of steak you eat (00:04:55) some steak that steak has potential (00:04:58) decaying type of organic material (00:05:00) the staphylococcus saprophytic survives (00:05:02) on that you eat that meat when you eat (00:05:05) the meat and then you decide to go ahead (00:05:07) and digest it and so on and so forth you (00:05:09) poop out some of the actual contents of (00:05:11) that actual substance (00:05:13) within the actual fecal matter that's (00:05:15) actually coming out of the gi tract near (00:05:17) the actual rectum area you're going to (00:05:19) have some staphylococcus saprophyticus (00:05:21) so it loves to colonize around an area (00:05:25) called the perennium so it's the you (00:05:27) know the perennium (00:05:29) so the perineum is the space between the (00:05:31) anus and the and the genitals right so (00:05:34) you can always remember i'd rather get (00:05:35) kicked in the perennial in the peroneal (00:05:38) region they get kicked in the perineum (00:05:39) right so it's the space between the anus (00:05:42) and the genitals so that saprophyticus (00:05:44) species will actually kind of colonize (00:05:46) within that perineum area now in females (00:05:49) their urinary urogenital tract is very (00:05:51) very in close proximity to the anus (00:05:55) and to the perennial area so what (00:05:57) happens is the actual bacteria can quick (00:05:59) and easily spread (00:06:02) to their actual urogenital tract and (00:06:04) colonize those areas as well so not only (00:06:06) will you find this in the perineum but (00:06:09) you may also find this within the (00:06:12) euro (00:06:15) genital tract (00:06:16) okay (00:06:17) but particularly more emphasis on the (00:06:19) urinary tract all right so it's a big (00:06:22) big thing i want you to remember (00:06:23) staphylococcus appropriatus survives on (00:06:25) decaying organic material usually it's (00:06:28) within the gi flora because you're (00:06:29) eating foods that it's contained on you (00:06:31) poop it out it actually stays within the (00:06:34) perineum and because the female urethra (00:06:36) is very very close proximity and short (00:06:38) it can easily kind of colonize into the (00:06:40) actual female urethra a part of the (00:06:42) urogenital tract all right beautiful we (00:06:45) have the three particular staphylococcal (00:06:47) species that i want you guys to remember (00:06:48) where you'll find them kind of where (00:06:50) they colonize what category of bacteria (00:06:52) they are non-motile facultative (00:06:54) anaerobes and going back to this concept (00:06:56) of their catalase positive what the heck (00:06:58) does that even mean (00:07:00) don't worry i gotcha (00:07:01) catalase positive means that these (00:07:03) bacteria staphylococcus aureus (00:07:06) staphylococcus epidermidis and (00:07:08) staphylococcus saprophyticus all contain (00:07:10) an enzyme called catalase (00:07:13) catalase is an enzyme that if you take (00:07:16) hydrogen peroxide (00:07:18) and you put that into like a petri dish (00:07:20) with all of these three bacteria this (00:07:22) the actual solution that when you put it (00:07:24) in there will bubble (00:07:25) why because they contain this catalase (00:07:28) enzyme that converts hydrogen peroxide (00:07:30) into water (00:07:32) and oxygen and the oxygen is what allows (00:07:33) for the kind of the bubbling effect so (00:07:36) one of the ways that you can identify (00:07:37) staphylococcus (00:07:39) these species is the process by which if (00:07:41) you do a test on them where you put them (00:07:43) in like a petri dish and you apply (00:07:44) hydrogen peroxide if the solution (00:07:46) bubbles it's catalase positive and all (00:07:49) of these are catalase positive so it's (00:07:51) not a way to differentiate them though (00:07:53) right so from this i can say that if (00:07:55) it's catalase positive i know it could (00:07:57) be staphylococcus aureus (00:08:00) it could be staphylococcus epidermidis (00:08:05) or it could be staphylococcus (00:08:07) saprophyticus (00:08:12) okay (00:08:13) now (00:08:14) we know that it's one of these three (00:08:15) based upon it being catalyzed positive (00:08:17) being gram positive being non-motile (00:08:18) facultative anaerobes how do we kind of (00:08:20) differentiate now between these three (00:08:23) bacteria we use another test that's (00:08:25) called a coagulase test (00:08:27) so coagulase is a very interesting (00:08:29) enzyme so coagulase (00:08:31) what coagulase is is this kind of like a (00:08:33) a prothrombin type of molecule and so (00:08:36) basically (00:08:38) coagulase will help in a process (00:08:41) of basically kind of converting a (00:08:43) particular molecule called (00:08:45) fibrinogen (00:08:48) into (00:08:49) fibrin (00:08:51) okay so coagulase will stimulate this (00:08:53) process the whole significance of this (00:08:56) is if you take a petri dish okay you put (00:08:58) these bacteria in them and you apply (00:09:01) some actual solution that contain you (00:09:03) apply some kind of like a colloid kind (00:09:05) of like solution (00:09:06) when you apply that solution if they (00:09:08) have coagulase (00:09:10) these bacteria they'll utilize the (00:09:12) fibrinogen within that colloid and kind (00:09:14) of con convert it into fibrin making (00:09:16) everything kind of like clump up so this (00:09:18) kind of will produce kind of like a (00:09:19) clumping (00:09:21) of the actual colloid solution (00:09:23) well guess of which ones actually clump (00:09:26) the staphylococcus aureus is the only (00:09:28) one of these that clumps up so therefore (00:09:31) we can say that this one is coagulase (00:09:35) positive (00:09:36) but all the other ones if you apply the (00:09:39) colloid solution to this in this (00:09:40) bacteria they do not actually produce (00:09:42) clumping therefore they do not contain (00:09:44) the coagulase enzyme so this one is (00:09:46) called these are called coagulase (00:09:49) negative (00:09:53) type of staphylococcus so so far we know (00:09:55) staphylococcus species are catalase (00:09:58) positive only staphylococcus aureus is (00:10:00) coagulates positive meaning that it can (00:10:02) convert fibrinogen to fibrin so if you (00:10:04) put all of these three bacteria into a (00:10:06) solution of colloid only this one will (00:10:08) lead to fibrin formation and clumping of (00:10:10) that solution (00:10:12) beautiful (00:10:13) the next thing that we can also do to (00:10:15) continue to keep differentiating these (00:10:17) staphylococci (00:10:19) is (00:10:20) you can taste staphylococcus aureus and (00:10:23) put it into something called a mannitol (00:10:25) salt auger you're like what the heck so (00:10:28) you can put it in this thing called a (00:10:30) mannitol (00:10:32) salt (00:10:33) agar (00:10:34) when you actually put the staphylococcus (00:10:37) aureus on the mannitol salt auger (00:10:40) it turns a very very special type of (00:10:42) color (00:10:43) it's kind of a golden (00:10:47) yellow type of colonies that you form (00:10:49) here (00:10:50) and that is where the arias term comes (00:10:53) from is golden yellow type of bacteria (00:10:56) so it's a cluster of golden yellow type (00:11:00) of bacteria is where you get the (00:11:01) staphylococcus aureus so one of the big (00:11:04) things to remember for staphylococcus (00:11:05) aureus (00:11:06) catalase positive coagulates positive (00:11:08) and will actually ferment on manitoba (00:11:12) salt augers and produce golden yellow (00:11:15) colonies very important (00:11:17) for staphylococcus epidermidis you then (00:11:20) have to differentiate this one from (00:11:23) staphylococcus saprophyticus how do you (00:11:25) do that because there's another similar (00:11:27) point between them they're both catalase (00:11:28) positive they're both coagulase negative (00:11:31) and guess what else they're both similar (00:11:32) in (00:11:33) if you were to take these bacteria (00:11:36) put them into a solution of what's (00:11:37) called a urea broth it's like what the (00:11:40) heck is this if you put them into (00:11:41) something called a urea (00:11:44) broth auger (00:11:46) which contains what's called a phenol (00:11:49) red which is kind of like a color (00:11:50) indicator basically a phenol red you put (00:11:53) both of these bacteria into this they're (00:11:56) going to be able to turn the color of (00:11:59) that actual solution into a very (00:12:01) beautiful pink color (00:12:03) and you're like what the heck how does (00:12:05) it do that (00:12:06) well (00:12:08) it contains a very very special enzyme (00:12:11) both of them contain a very very special (00:12:12) enzyme so they contain an enzyme called (00:12:15) urease so both of them contain an enzyme (00:12:18) called (00:12:19) urease so they're what's called urease (00:12:21) positive (00:12:22) okay (00:12:23) meaning that if you put these bacteria (00:12:25) into the solution of urea broth they'll (00:12:27) use that urea and convert the urea into (00:12:31) ammonia ammonia is a base and when it (00:12:33) kind of works with the phenol red which (00:12:35) is kind of like the color indicator it (00:12:37) changes that actual kind of indicator (00:12:39) into more of a pinkish beautiful color (00:12:42) and so both staphylococcus epidermidis (00:12:45) and saprophyticus are catalase positive (00:12:47) coagulates negative urease positive how (00:12:51) are they actually different then (00:12:53) here's the next test (00:12:55) you take an antibiotic (00:12:57) so you take these bacteria and you put (00:12:59) them on something called (00:13:00) novobiosin (00:13:03) it's basically an antibiotic right so (00:13:05) i'm going to put both of them on (00:13:07) novobias and i'm going to take both of (00:13:08) these bacteria put them on a petri dish (00:13:12) and i'm going to put this antibiotic i'm (00:13:14) going to kind of like slap an antibiotic (00:13:16) right here in the center of that petri (00:13:17) dish where all the bacteria (00:13:19) is the one that actually causes colonies (00:13:22) to die off (00:13:24) so let's say that this one starts to die (00:13:26) off (00:13:27) so some of the bacteria die off around (00:13:30) the novobiosin because it's able to kill (00:13:32) some of those bacteria (00:13:33) this means (00:13:34) that they're noble biasing sensitive (00:13:37) that means they're sensitive to it and (00:13:38) it can actually kill them (00:13:40) so those that are actually novo (00:13:43) biasing (00:13:45) sensitive (00:13:47) is what staphylococcus epidermidis (00:13:51) if you did it on this one which is the (00:13:53) staphylococcus appropriaticus guess what (00:13:55) do you think they're going to be any (00:13:56) change any dying off of the colonies no (00:13:59) so they're resistant to the novobiosin (00:14:02) so they'll still be able to survive even (00:14:04) despite the novobiosin being within that (00:14:07) solution there so these are called (00:14:08) novobiosin (00:14:10) resistant so to quickly summarize some (00:14:12) of the tests that you need to be able to (00:14:14) remember for your exams staphylococcus (00:14:17) species gram positive non-motile (00:14:18) facultative anaerobes (00:14:20) they're all catalyzed positive staph (00:14:22) aureus is the only one that's coagulates (00:14:24) positive and can grow golden yellow (00:14:26) colonies on the manitoba salt auger (00:14:29) staphylococcus epidermidis and (00:14:30) saprophyticus are coagulase negative and (00:14:33) urea is positive but they differ in (00:14:35) their sensitivity or resistance to (00:14:37) novobiosin where the staphylococcus (00:14:40) epidermidis is novobias insensitive and (00:14:42) the staphylococcus appropriatis is nova (00:14:44) biasing resistant now that we understand (00:14:46) this let's actually start talking about (00:14:48) the pathology and how these actual (00:14:50) bacteria cause disease all right (00:14:53) engineers let's talk about (00:14:54) staphylococcus aureus so we're going to (00:14:56) go through now kind of like the (00:14:57) pathophysis (00:14:58) to explain how do these actual bacteria (00:15:01) that now we've kind of differentiated (00:15:03) how do they actually cause infections (00:15:05) and then what kind of diseases (00:15:07) can you actually see as a result from (00:15:09) these pathogenic mechanisms (00:15:12) let's talk about staphylococcus aureus (00:15:13) so staphylococcus aureus has a couple (00:15:16) different ways that it can cause a lot (00:15:17) of nasty damage (00:15:20) there's two particular ways one is by a (00:15:22) biofilm and we'll talk about that one (00:15:24) first (00:15:25) and the second one (00:15:27) is they release something called (00:15:29) exotoxins (00:15:31) okay and we'll talk about all the (00:15:33) particular types of exotoxins that the (00:15:35) staphylococcus aureus can release and (00:15:36) all the damage that they can actually do (00:15:38) okay (00:15:40) so first thing is it causes biofilms (00:15:42) what the heck is a biofilm and why is (00:15:44) that even significant so the first thing (00:15:46) that these actual staphylococcus aureus (00:15:49) bacteria can do is they can lead to (00:15:50) these things called biofilms another (00:15:53) kind of term that we use is they make (00:15:54) what's called an exo (00:15:56) polysaccharide layer or an eps (00:15:59) so let's say you guys take for example (00:16:02) uh you're going to be doing like a (00:16:03) venipuncture of some kind okay you're (00:16:05) going to be trying to puncture or put in (00:16:07) an iv okay (00:16:08) when you puncture or put in an iv of (00:16:10) some kind you're trying to go into a (00:16:12) vein (00:16:13) you have to go through the skin well (00:16:15) guess what's a part of our skin flora (00:16:17) staphylococcus aureus if you puncture (00:16:19) and some of the bacteria get onto the (00:16:21) needle and then into the needle they (00:16:24) actually go into the vein (00:16:26) they now can kind of get introduced into (00:16:28) the bloodstream and they're kind of like (00:16:29) on that actual that venous catheter (00:16:32) right there (00:16:33) what they'll start doing is (00:16:35) they'll start to secrete (00:16:38) a kind of polysaccharide layer (00:16:42) a loose polysaccharide layer around them (00:16:45) so imagine all of this loose (00:16:46) polysaccharide layer around these (00:16:48) bacteria (00:16:49) you know what's interesting about this (00:16:52) it allows for the bacteria to be able to (00:16:54) cross talk with one another pass on (00:16:56) genetic material pass on cell signaling (00:16:58) mechanisms and they have this really (00:17:00) thick kind of polysaccharide covering (00:17:02) why is that important because you know (00:17:04) what that's significant (00:17:06) immune system cells (00:17:08) may not be able to break through that (00:17:10) actual actual polysaccharide layer (00:17:12) antibiotics (00:17:14) which you want to be able to kill the (00:17:16) bacteria may not be able to penetrate (00:17:19) through (00:17:20) that exopolysaccharide layer and so (00:17:22) because of that that can make it (00:17:24) difficult for infections to be able to (00:17:25) be treated by antibiotics (00:17:28) and it can make it difficult for the (00:17:30) immune system to actually break down the (00:17:31) bacteria because they have this (00:17:33) exopolysaccharide that's preventing them (00:17:35) from being able to get to the bacteria (00:17:37) and so you can see this with intravenous (00:17:40) catheters or certain types of catheter (00:17:41) associated infections okay so you want (00:17:44) to remember that sometimes these (00:17:45) biofilms can lead to what's called (00:17:47) catheter (00:17:49) associated (00:17:52) infections (00:17:54) all right beautiful (00:17:56) that's one thing the second thing is all (00:17:59) of these exotoxins (00:18:00) and there's so many of these exotoxins (00:18:03) let's talk about the first type of (00:18:05) exotoxin (00:18:08) the first type of exotoxin that i want (00:18:09) you guys to remember here is what's (00:18:12) called (00:18:13) the toxic shock syndrome type one so the (00:18:16) first one here is called (00:18:18) toxic shock syndrome toxin type one (00:18:23) when staphylococcus aureus gets into the (00:18:25) actual body right what it does is it can (00:18:28) release this nasty nasty toxin and this (00:18:30) toxin will bind on and act as what's (00:18:33) called a super antigen so you know (00:18:35) antigen presenting cells they have these (00:18:37) things called mhc2 complexes and they (00:18:40) love to interact with other kinds of (00:18:42) cells here like your t cells (00:18:44) so you can also have t cells which want (00:18:45) to interact with these image c2 (00:18:47) complexes via their cd4 and tcrs and all (00:18:50) of that stuff (00:18:51) what happens is the toxic shocks in germ (00:18:53) toxin type 1 will actually kind of lead (00:18:56) to a bridging interaction between the t (00:18:58) cell and the antigen presenting cell (00:19:01) and stimulate and hyperstimulate their (00:19:03) actual immune response (00:19:05) leading to a massive release of (00:19:07) cytokines like interleukin-1 (00:19:09) interleukin-2 (00:19:11) tnf alpha (00:19:13) and even like interferon gamma (00:19:16) all of these molecules cause a massive (00:19:19) inflammatory reaction and lead to three (00:19:21) particular things that you need to (00:19:23) remember one is they can act on (00:19:26) the skin (00:19:28) son of a gun sorry guys i literally just (00:19:30) lost my dang marker so again what (00:19:32) happens is these these cytokines they (00:19:34) act on the skin right and what they can (00:19:36) do is they can cause a really nasty rash (00:19:40) okay so they can cause some rash and (00:19:41) basically some inflammation of the skin (00:19:44) second thing they can do is they can (00:19:45) also increase capillary permeability (00:19:47) cause vasodilation of the blood vessels (00:19:49) which can lead to hypotension (00:19:52) so low blood pressure (00:19:54) and they can also act on the (00:19:56) hypothalamus increasing the (00:19:57) prostaglandin e2 release increasing your (00:19:59) body's internal temperature (00:20:01) leading to (00:20:02) fever (00:20:04) and these three things combine rash (00:20:06) hypotension and fever lead to something (00:20:09) called toxic shock syndrome (00:20:12) this is something that you can see with (00:20:13) staphylococcus aureus whenever the (00:20:15) bacteria are thriving on particular (00:20:18) types of things that have stayed within (00:20:20) the body for a little bit too long the (00:20:22) classic example is like tampons that (00:20:24) were left in for too long never actually (00:20:26) taken out and the bacteria can actually (00:20:28) survive on that and release that toxic (00:20:30) shock syndrome type toxin type 1 leading (00:20:33) to rash hypotension and fever or nasal (00:20:35) packing that stays in for a long time (00:20:37) without any kind of like (00:20:38) antibiotic impregnation on it of some (00:20:41) kind or maybe you had a surgery and they (00:20:42) left like a lap pad in there and that (00:20:44) form material also contained the (00:20:46) staphylococcus aureus and it started (00:20:47) releasing some of that toxins (00:20:49) so those are examples that you guys need (00:20:51) to remember so this is the first type (00:20:54) the second toxin that i want you guys to (00:20:56) remember is what's called a leukocytin (00:21:00) it's called a leuco (00:21:02) in toxin (00:21:04) it's actually called palin valentine (00:21:06) leukocyte and protein or exotoxin and (00:21:09) what this actually does is (00:21:11) this sky actually comes and creates (00:21:13) pores (00:21:15) inside of particular types of leukocytes (00:21:19) so it creates little pores or membranes (00:21:21) with inside leukocytes that leads to (00:21:24) particular types of ions or different (00:21:26) things to float in and out of these (00:21:27) actual white blood cells leading to (00:21:29) these white blood cells undergoing (00:21:31) necrosis (00:21:32) and then what happens is when these (00:21:34) white blood cells actually undergo (00:21:35) necrosis and die it leads to a massive (00:21:38) amount of inflammation (00:21:40) and this is very common in a particular (00:21:42) area of the body like in the lungs so (00:21:44) whenever this inflammation occurs it (00:21:46) starts causing damage to some of the (00:21:48) actual parenchymal lung tissue and some (00:21:51) of these actual tissue cells in the lung (00:21:52) actually undergo necrosis as well and (00:21:55) this can lead to what's called a (00:21:56) necrotizing (00:21:59) pneumonia that you can sometimes see (00:22:01) with staphylococcus aureus due to the (00:22:04) leukocyte and exotoxin (00:22:06) okay what else so we got toxic shock (00:22:08) syndrome type toxin type one we got (00:22:10) leukocytin we even covered the biofilms (00:22:13) the third thing that we got to talk (00:22:14) about (00:22:15) there's another type of exotoxin and (00:22:18) this is called an exfoliative toxin (00:22:23) so this is called the exfoliative toxin (00:22:26) you might even get the name by this (00:22:29) exfoliation so it probably has something (00:22:31) to do with the skin yes it does there is (00:22:34) a really really nasty disease that you (00:22:36) can see from this (00:22:38) and we'll talk about in a second called (00:22:39) staphylococcal scolded skin syndrome or (00:22:41) ritter's disease (00:22:43) what happens is this toxin (00:22:45) loves to lead to it targets a very (00:22:48) particular protein you know these skin (00:22:49) cells here you know within our skin we (00:22:51) have very particular skin cells we (00:22:52) actually have what are they called (00:22:54) they're called keratinocytes right so (00:22:55) these are called (00:22:57) caratino (00:22:59) sites (00:23:00) in between the keratinocytes there's (00:23:02) particular cell adhesion molecules that (00:23:04) link them together really really tightly (00:23:06) and these this the protein that's (00:23:08) incorporated into that is called (00:23:10) desmoglian type one (00:23:12) exfoliative toxins love to lead to the (00:23:15) damage or the destruction of desmoglian (00:23:18) one with between these carotenocytes (00:23:21) if you start to damage this (00:23:23) the connection between these (00:23:25) keratinocytes is lost so they're no (00:23:27) longer able to kind of stay stuck (00:23:29) together really well (00:23:30) if your skin cells aren't able to stay (00:23:32) stuck together very well we'll start (00:23:34) happening it'll start forming blisters (00:23:37) and eventually those blisters will (00:23:38) actually slough off and they'll start (00:23:40) losing skin from there and that can lead (00:23:42) to this condition called staphylococcal (00:23:44) scolding skin syndrome that you can see (00:23:46) in kids usually like less than six years (00:23:48) of age (00:23:50) okay so we got biofilm we got our toxic (00:23:53) shock syndrome toxin type 1 our (00:23:54) leukocyte and our exfoliative toxin (00:23:57) there's another type of exotoxin that's (00:23:59) released from this bacteria and some of (00:24:01) the negative effects of it (00:24:04) this is it also releases a nasty type of (00:24:07) hemolysin (00:24:08) so it can release something called a (00:24:10) hemolysin and via an enzyme called (00:24:12) beta-hemolysin so it's actually called (00:24:13) beta-hemolysin (00:24:15) this is another type of exotoxin that (00:24:17) can actually lead to the destruction of (00:24:19) the red blood cell membrane you know it (00:24:22) destroys the red blood cell membrane and (00:24:24) when it destroys the red blood cell (00:24:25) membrane it leads to the (00:24:27) hemoglobin being released out from here (00:24:29) and then the hemoglobin will also get (00:24:31) destroyed so one of the big things that (00:24:33) you can see from this is this can lead (00:24:34) to what's called red blood cell (00:24:36) destruction (00:24:39) this is a very important concept okay (00:24:41) because you know staphylococcus aureus (00:24:43) another thing that you can do is (00:24:44) you when you actually do testing of this (00:24:46) you can take like a petri dish let's say (00:24:48) for example (00:24:49) let's say here we have like a a plate (00:24:51) here a blood auger okay (00:24:54) you take a blood auger so you basically (00:24:56) take and you have blood (00:24:58) cells on this actual plate and then you (00:25:00) put some of the staphylococcus species (00:25:02) on (00:25:03) this actual plate (00:25:04) when you do that the staphylococcus (00:25:06) aureus will release (00:25:08) beta-hemolysins (00:25:09) and when it releases the beta-hemolysins (00:25:12) it'll cause destruction of red blood (00:25:14) cells on the actual blood locker plate (00:25:16) so what will you get you'll get little (00:25:18) empty spots where no blood is why (00:25:20) because the staphylococcus aureus was (00:25:22) causing destruction of those red blood (00:25:24) cells which again you can get through (00:25:26) this test here okay so whenever you put (00:25:28) staphylococcus aureus on a blood auger (00:25:29) plate and you see empty spots it's (00:25:31) because of that and exotoxin okay (00:25:35) the last thing for this one is that (00:25:37) there wasn't enough (00:25:38) is (00:25:39) it also releases one last exotoxin and (00:25:42) this is called enterotoxin (00:25:44) and you can already probably guess what (00:25:46) this one does (00:25:48) the enterotoxin is an exotoxin that (00:25:50) actually targets some of the (00:25:53) in enterocytes within the epithelial (00:25:57) lining of the gi tract it targets them (00:26:00) it produces different types of pores and (00:26:02) dysfunctional proteins with inside of (00:26:04) actually at least the destruction of the (00:26:06) actual cell membrane okay within these (00:26:08) actual enterocytes and then what happens (00:26:10) is some of the sodium and water which is (00:26:12) inside of those actual cells (00:26:14) leak out and the intestinal cells aren't (00:26:16) able to do their function which is (00:26:17) absorb nutrients absorb water absorb (00:26:20) electrolytes so you start losing that (00:26:22) function of being able to absorb (00:26:24) particular types of chemicals and so as (00:26:26) a result if there is a decreased (00:26:28) absorption (00:26:30) and there's a lot of electrolyte like (00:26:32) we'll put positive negative because (00:26:33) there's different types of electrolytes (00:26:35) that are shifting around back and forth (00:26:37) between the actual gi tract so there's (00:26:39) decreased absorption a lot of (00:26:41) electrolyte shifts guess what's going to (00:26:42) happen (00:26:45) you're going to start peeing out your (00:26:46) butt okay and this is going to lead to a (00:26:48) lot of diarrhea (00:26:50) and it's also going to lead to a lot of (00:26:52) inflammation because it's damaging the (00:26:54) actual epithelial lining of the gi tract (00:26:55) which is going to lead to a (00:26:57) gastroenteritis so one of the effects (00:26:59) out of this is you can see something (00:27:01) called (00:27:02) gastroenteritis (00:27:05) and usually this happens within like (00:27:07) anywhere like less than six hours (00:27:10) after eating some type of food (00:27:13) that like you know usually the example (00:27:14) that they use in the uh in the exams (00:27:16) is some type of like mayonnaise (00:27:19) containing type of a food it's very rich (00:27:21) within staphylococcus aureus potentially (00:27:24) that allows for it to be able to produce (00:27:26) this negative gastroenteritic-like (00:27:27) effect all right so that covers our (00:27:30) staphylococcus aureus and how it causes (00:27:32) these pathogenic mechanisms we'll (00:27:33) explain in a little bit (00:27:36) how all of these pathogenic mechanisms (00:27:38) produce very specific diseases okay (00:27:42) let's now before we do that cover how (00:27:44) the pathogenic mechanisms of epidermidis (00:27:47) and saprophyticus of staphylococci (00:27:48) species also have pathogenic mechanisms (00:27:51) all right so staphylococcus epidermidis (00:27:52) this is a really cool guy as well so (00:27:55) again we know that this is a part of our (00:27:56) natural skin flora (00:27:58) and so the main mechanism by which this (00:28:00) bacteria produces particular types of (00:28:03) diseases is by it forming those things (00:28:05) called biofilms and we already kind of (00:28:08) understand how it does that it remember (00:28:09) it excretes that nice little like (00:28:11) exopolysaccharide kind of covering (00:28:12) around it that allows for it to be able (00:28:14) to be resistant against antibiotics (00:28:16) potentially and evade the immune system (00:28:19) now (00:28:20) what kind of things would it love to (00:28:22) form biofilms on this is a very (00:28:24) important thing it loves to form (00:28:27) biofilms (00:28:29) on kind of like intravascular catheters (00:28:31) so you would see this forming a biofilm (00:28:33) on like vascular catheters (00:28:36) so vascular devices of some kind (00:28:39) you would see this forming kind of a (00:28:40) really nice (00:28:42) biofilm on (00:28:44) urinary catheters (00:28:48) and you know what else (00:28:51) it loves to form (00:28:53) on particular types of prostatic devices (00:28:56) that are basically inserted into the (00:28:58) body especially prosthetic valves (00:29:04) and joints (00:29:07) prosthetic joints (00:29:12) okay so it's really important to (00:29:13) remember that these can form biofilms on (00:29:15) prosthetic valves they can form (00:29:17) prosthetic (00:29:18) biofilms on prosthetic joints they can (00:29:20) form biofilms on urinary catheters and (00:29:22) biofilms on vascular devices the main (00:29:25) concept behind this is that whenever (00:29:26) you're actually (00:29:27) inserting in a catheter you're going (00:29:29) through the skin staphylococcus (00:29:30) epidermidis is a part of our natural (00:29:32) skin flora (00:29:33) if you're actually inserting a urinary (00:29:36) catheter or foley catheter into the (00:29:37) bladder you have to pass through the (00:29:39) skin near the actual urinary tract (00:29:41) staphylococcus epidermidis is near that (00:29:43) area (00:29:44) again prostatic joints if you're putting (00:29:46) in an actual prosthesis whether it be (00:29:48) into the heart or into an actual area of (00:29:50) a joint like a hip joint you're having (00:29:52) to open up the individual and allowing (00:29:54) for you to when you open up the actual (00:29:56) skin or open up the area to access that (00:29:58) particular area you're allowing for (00:30:00) potentially putting in (00:30:02) a prosthetic device that could be (00:30:05) covered by staphylococcus epidermidis (00:30:07) once it's actually inside it can create (00:30:09) the exopolysaccharide covering or (00:30:11) biofilm allowing for it to be able to (00:30:14) produce certain types of diseases or (00:30:16) infections (00:30:18) and then (00:30:19) again be potentially resistant to (00:30:21) antibiotics okay all right so we have (00:30:23) staphylococcus saprophyticus now this (00:30:25) one also again very very interesting can (00:30:27) produce its kind of like diseases or (00:30:30) it's it's really nastiness by the (00:30:32) process of things called biofilms and we (00:30:35) already have a pretty good understanding (00:30:36) of this it produces that (00:30:37) exopolysaccharide (00:30:39) but the other mechanism by which it can (00:30:41) actually really kind of cause (00:30:42) problematic issues (00:30:44) is that urease enzyme the staphylococcus (00:30:46) epidermidis also has the urease enzyme (00:30:49) but again i want us to really really (00:30:52) hone in on it with staphylococcus (00:30:53) saprophyticus so again let's say that (00:30:55) you're putting in a foley catheter a (00:30:57) person has urinary retention you're (00:30:58) trying to monitor their uh you know (00:31:00) their intake and output stuff like that (00:31:01) right and so you put in this catheter (00:31:03) when you go through that area you're (00:31:05) going to be touching the skin of some (00:31:07) kind near the urinary tract and probably (00:31:09) pick up some of the staphylococcus (00:31:10) approviticus (00:31:12) and so therefore it may kind of like be (00:31:14) on the urinary catheter of some kind (00:31:16) okay and it has the ability to produce (00:31:18) the biofilms we already know that which (00:31:19) can make it resistant to potentially (00:31:20) antibiotics we know it can kind of evade (00:31:22) the immune system the whole nine yards (00:31:24) but here's what makes it even worse (00:31:26) a staphylococcus hypophyticus has this (00:31:28) urease enzyme you know the ph inside of (00:31:31) our the ph of our urine is usually low (00:31:33) you want it to be kind of acidic it's (00:31:35) harder for bacteria to thrive in acidic (00:31:36) environments the protons kind of alter (00:31:38) they kind of lead to the denaturation of (00:31:40) enzymes and dna so on and so forth so (00:31:43) what this urease enzyme does is you know (00:31:45) with inside (00:31:47) of the urine there's a particular (00:31:48) molecule called urea (00:31:51) the urease enzyme which is from the the (00:31:54) staphylococcus approviticus it'll (00:31:56) release the urease enzyme (00:31:58) and the urease will then do something (00:32:00) very interesting it'll break down urea (00:32:03) into two components (00:32:05) it'll break it down into co2 (00:32:08) and it'll break it down (00:32:10) into ammonia now ammonia is a base (00:32:13) okay so what this is going to do is is (00:32:16) it's going to bring the ph (00:32:19) back up (00:32:20) if you increase the ph you can increase (00:32:24) bacterial growth (00:32:26) because now it's easier for bacteria to (00:32:29) grow in higher ph environments pretty (00:32:31) cool right (00:32:33) and not for us but for the bacteria it (00:32:35) is another thing is that (00:32:37) mag this um ammonia will combine with (00:32:40) some of the other solutes present within (00:32:42) our urine (00:32:43) magnesium (00:32:45) is a very interesting solute that's (00:32:46) present within our urine (00:32:48) sulfate is another a molecule that's (00:32:51) present within our urine (00:32:52) and so what happens is the sulfate and (00:32:55) the magnesium combine with the ammonia (00:32:58) and lead to something called struvites (00:33:02) okay so struvite crystals (00:33:05) and this can produce little types of (00:33:06) stones and those stones can potentially (00:33:09) obstruct (00:33:11) parts of the urinary tract now remember (00:33:13) the foley catheter is one way by which (00:33:16) we can introduce (00:33:17) the bacteria into the actual bladder (00:33:20) that's not the only way remember what i (00:33:22) told you if you're a back to front wiper (00:33:25) for females you take the potential of (00:33:27) wiping that bacteria from the area of (00:33:29) the perineum near the urinary tract and (00:33:32) then the bacteria can travel up the (00:33:34) actual urethra and into the bladder so (00:33:36) there's a couple ways that we can get it (00:33:38) in there once it's in there it has this (00:33:40) ability to produce biofilms or change (00:33:43) the ph and they know what else it can do (00:33:45) it can produce these struvite crystals (00:33:48) which can kind of lead to (00:33:50) like a obstruction of some kind like a (00:33:52) urinary outflow tract obstruction maybe (00:33:54) it produces like a little stone (00:33:55) somewhere within the bladder or within (00:33:57) the urinary tract somewhere and that can (00:33:59) also cause problematic issues as well (00:34:01) okay (00:34:02) so that is all the kind of pathogenic (00:34:05) mechanisms of the staphylococcus (00:34:06) bacteria now let's talk about the (00:34:08) diseases that we actually see as a (00:34:10) result of these pathogenic mechanisms (00:34:12) all right so let's talk about how (00:34:13) staphylococcus aureus through the kind (00:34:15) of pathogenic mechanisms (00:34:17) leads to particular types of diseases (00:34:19) one of the big ones is skin infections (00:34:21) we see a lot of skin soft tissue (00:34:22) infections with staphylococcus aureus (00:34:24) right now (00:34:25) not everybody's just walking around with (00:34:27) staph infections every single day it's a (00:34:29) part of our skin flora right (00:34:30) but if you have big breaks within the (00:34:33) skin and you have heavy amounts of (00:34:34) staphylococcus aureus in this on the (00:34:36) skin and they invade in through that (00:34:38) break within the skin it can then lead (00:34:40) to (00:34:41) tissue damage causing lots of white (00:34:42) blood cell inflammation lots of white (00:34:44) blood cells coming to the area leading (00:34:46) to inflammation leading to redness (00:34:48) leading to pain and this can lead to a (00:34:50) lot of different skin and soft tissue (00:34:51) infections for example if there's like (00:34:54) an infection or inflammation around like (00:34:55) a hair follicle this can lead to (00:34:57) something called a (00:34:59) frunkle (00:35:00) and a bunch of for uncles can come (00:35:02) together and lead to a carbuncle (00:35:05) so just big old boils (00:35:07) the next thing is if it just infects (00:35:10) like the actual um aspect of this the (00:35:13) epidermis you know sometimes there's (00:35:14) staphylococcus aureus that can infect (00:35:16) just the epidermis and this can lead to (00:35:18) something like an impetigo (00:35:22) if it starts to infiltrate into like not (00:35:24) only the epidermis but starts involving (00:35:26) like the dermis this can lead to a (00:35:29) cellulitis (00:35:31) and not only that but if the infection (00:35:34) starts actually spreading into the (00:35:36) dermis and starts causing lots of (00:35:37) bacteria to come into the area and your (00:35:40) immune system your bacteria immune (00:35:42) system white blood cells all of that (00:35:43) stuff broken down cellular debris you (00:35:45) try to wall off that infection your (00:35:47) immune system tries to do that and you (00:35:49) lead just to like a big old sack of pus (00:35:52) with inside of the the actual dermis (00:35:54) this can lead to something like an (00:35:55) abscess (00:35:58) okay (00:35:59) so big things to remember is skin soft (00:36:01) tissue infections again infection of (00:36:03) like like the hair like the hair (00:36:04) follicles particularly like for uncles (00:36:06) and then potentially becoming a (00:36:07) carbuncle infections just of the (00:36:09) epidermis like an impetigo infections of (00:36:12) the dermis like the cellulitis and then (00:36:14) if you lead to a walled off infection (00:36:15) containing cellular debris bacteria (00:36:17) white blood cells this can lead to an (00:36:19) abscess (00:36:20) now (00:36:22) here's what's even more interesting (00:36:23) these bacteria (00:36:25) if you get something like a cellulitis (00:36:27) or an abscess (00:36:29) these bacteria can continuously spread (00:36:32) through the dermis through the (00:36:33) subcutaneous tissue into the underlying (00:36:35) structures what's below the fat tissue (00:36:37) within our arm (00:36:39) you start getting into like particularly (00:36:41) connective tissue muscle tissue bones (00:36:44) joints (00:36:45) if this actual let's say here's the (00:36:47) infection right here (00:36:48) right (00:36:49) if these bacteria spread and they spread (00:36:52) to the muscle they can lead to (00:36:54) inflammation and infection of the actual (00:36:56) muscle leading to what's called like a (00:36:58) piyo (00:36:59) myositis (00:37:01) if they infiltrate into the actual bone (00:37:04) tissue and lead to infections of the (00:37:06) bone tissue and damage and destruction (00:37:08) of the bone tissue this can lead to (00:37:09) something called osteomyelitis (00:37:13) if they start infecting the actual (00:37:15) joints (00:37:16) and leading to inflammation and (00:37:18) infections of the actual joints this can (00:37:20) lead to a (00:37:21) septic arthritis (00:37:25) so from an actual infection like (00:37:27) cellulitis and abscess of a skin soft (00:37:29) tissue if they're able to infiltrate (00:37:32) deep from that area contiguously it can (00:37:35) then lead to pile myositis (00:37:36) osteomyelitis or even a septic arthritis (00:37:40) so that's something else to think about (00:37:42) now (00:37:43) not only could they contiguously spread (00:37:45) through the skin and soft tissues into (00:37:47) like the area of the bone and joints but (00:37:49) you know what else you have nearby (00:37:52) you have little blood vessels right so (00:37:53) you have blood vessels here (00:37:56) what if the bacteria spreads into the (00:37:58) blood (00:37:59) and then from the blood you have (00:38:00) something called bacteremia bacteremia (00:38:02) is just basically when you have that (00:38:04) blood that bacteria within the blood so (00:38:06) there's a bunch of bacteria within the (00:38:07) blood bacteremia well look what happens (00:38:10) here bacteremia can be somewhat a normal (00:38:12) process and not lead to a bunch of (00:38:14) issues but if the actual bacteria within (00:38:17) the bloodstream start causing disease (00:38:19) and start causing significant infections (00:38:22) you start looking at more of kind of a (00:38:23) septicemia kind of effect here (00:38:26) if the bacteria gets into the (00:38:28) bloodstream (00:38:29) okay and it starts doing something else (00:38:32) it starts invading into tissues via this (00:38:35) hematogenous route so it's spreading (00:38:37) contiguously so through the skin through (00:38:39) the soft tissue causing these infections (00:38:41) but if it's able to invade into the (00:38:43) bloodstream and then go and infect other (00:38:46) organs (00:38:46) through the blood that's the (00:38:47) hematogenous spread okay let's say that (00:38:51) it spreads (00:38:52) and infects the meninges (00:38:54) leading to something like (00:38:57) meningitis so you can develop a (00:38:59) meningitis due to staphylococcus aureus (00:39:01) maybe it leads to an abscess so not only (00:39:03) get infected inflammation and infection (00:39:05) of the meninges maybe you get like an (00:39:07) abscess in the brain so it can lead to a (00:39:09) brain abscess (00:39:12) that is another thing to think about as (00:39:14) well (00:39:15) what if the bacteria spread through the (00:39:17) blood and they get into the lungs (00:39:19) and they start causing an inflammation (00:39:21) and infection of lungs this can lead to (00:39:24) pneumonia you know what is really (00:39:25) important about this for the exams you (00:39:27) usually see this in elderly people after (00:39:29) they've been infected with the flu that (00:39:31) is a super important thing to remember (00:39:32) so if someone starts developing a (00:39:34) bacterial lung infection and they're (00:39:36) elderly and they ask you like what is a (00:39:37) particular thing that would is a risk (00:39:39) factor to them having this it's them (00:39:41) having a previous influenza infection so (00:39:43) don't forget that for your exams (00:39:45) the other thing is what if these (00:39:47) bacteria not only spread to the lungs (00:39:49) but they also spread to the heart and (00:39:51) you know they love to attack (00:39:53) they love to attack the valves (00:39:56) they love to attack the heart valves and (00:39:58) when they attack the heart valves they (00:40:00) start leading to a lot of infectious (00:40:02) vegetations on the heart valves and this (00:40:04) can lead to what's called (00:40:06) an infective (00:40:09) endocarditis (00:40:12) it can lead to an infective endocarditis (00:40:14) so one of the big things that i want you (00:40:16) guys to remember (00:40:18) is that staphylococcus aureus can cause (00:40:20) skin and soft tissue infections can (00:40:22) spread contiguously (00:40:23) through the skin soft tissue to areas (00:40:25) nearby like the muscles the joints and (00:40:27) the bones leading to these infections (00:40:29) they can spread through that actual skin (00:40:31) soft tissue infection into the blood (00:40:34) leading to these things like meningitis (00:40:35) brain abscess pneumonia and infective (00:40:37) endocarditis you know what else (00:40:40) what if you're an iv drug abuser what if (00:40:42) you just had surgery (00:40:43) what if there was some other reason by (00:40:46) which it wasn't actually spread through (00:40:47) an infection of the skin it was (00:40:49) introduced through some kind of like (00:40:51) foreign like needle okay for example (00:40:55) if someone is a (00:40:57) iv drug abuser (00:40:58) that is a big big risk factor for (00:41:00) spreading staphylococcus aureus (00:41:02) and another thing is some kind of (00:41:04) surgical procedure so another thing is (00:41:07) any kind of surgery maybe dental work (00:41:08) maybe you're actually opening up (00:41:10) different areas and allowing for that (00:41:11) staphylococcus aureus to get spread but (00:41:13) please don't forget iv drug use is a big (00:41:15) big way by which staphylococcus aureus (00:41:18) can get spread okay (00:41:21) all right that's the ways that i want (00:41:22) you guys to remember the big kind of (00:41:25) infections (00:41:26) to go back and quickly review how some (00:41:28) of the exotoxins can produce very (00:41:30) specific types of diseases do you guys (00:41:33) remember what it was called whenever you (00:41:35) had a rash (00:41:36) hypotension and fever (00:41:39) due to having a tampon just sitting in (00:41:41) that area for too long (00:41:44) toxic shock syndrome right due to toxic (00:41:46) shock syndrome toxin type 1 (00:41:48) inducing these effects leading to (00:41:51) toxic shock syndrome (00:41:57) boom (00:41:58) the last thing is do you guys remember (00:41:59) what was the name of the actual toxin (00:42:02) that caused destruction (00:42:05) of (00:42:06) the desmoglin (00:42:08) it was the exfoliative toxin and that (00:42:10) exfoliative toxin was actually leading (00:42:11) to destruction of the desmoglin leading (00:42:14) to separation between the keratinocytes (00:42:16) causing a lot of inflammation and then (00:42:19) leading to kind of a red rash (00:42:22) that then progresses to blisters (00:42:25) and these blisters (00:42:27) actually if you just take and rub over (00:42:29) it it'll cause the blister to like open (00:42:31) up and the skin to slough what is that (00:42:33) called there's a very specific name for (00:42:35) that (00:42:36) it's called a positive (00:42:39) nikolsky's sign (00:42:43) so that's a big thing to remember and (00:42:45) this is something that you see with a (00:42:46) very specific disease called (00:42:48) staphylococcal scolded skin (00:42:51) syndrome staphylococcal scalded skin (00:42:53) syndrome also known as ritter's disease (00:42:56) the last type of effect that we can also (00:42:58) see from staphylococcus aureus not (00:43:00) directly but via its exotoxin is the (00:43:02) enterotoxin effect right so we talked (00:43:04) about this also briefly the enterotoxin (00:43:07) can also lead to destruction of the (00:43:09) epithelial lining of the gi tract (00:43:11) and it's going to alter the absorption (00:43:13) it's going to alter the ability for (00:43:16) movement of electrolyte it's going to (00:43:17) lead to electrolyte shifts and it's (00:43:18) going to basically lead to diarrhea and (00:43:21) from this we can see things like gastro (00:43:24) enteritis (00:43:26) usually secondary to (00:43:29) some type of food poisoning so usually (00:43:31) secondary to (00:43:33) food poisoning and remember what i told (00:43:34) you to remember it's usually some type (00:43:36) of like mayonnaise mayonnaise-based type (00:43:38) of food substance okay so that is all (00:43:41) the diseases (00:43:43) and syndromes that we can see associated (00:43:45) with staphylococcus aureus let's briefly (00:43:47) cover epidermidis and saprophyticus all (00:43:50) right so staphylococcus epidermidis we (00:43:52) talked about how it's a part of our (00:43:53) natural skin flora and it loves to kind (00:43:55) of basically hang on to particular types (00:43:58) of foreign devices one is we said (00:44:00) vascular devices right and we said that (00:44:02) it can lead to (00:44:03) catheter associated so we can maybe get (00:44:05) some type of catheter (00:44:08) associated (00:44:11) infections (00:44:13) for example like if someone has like a (00:44:15) central venous catheter and like a (00:44:17) subclavian vein or an internal jugular (00:44:18) vein or moral vein it may lead biofilms (00:44:21) on that type of catheter therefore (00:44:23) leading to infections here's a really (00:44:24) really really high yield topic that you (00:44:27) have to remember it's also a very (00:44:28) important clinical topic to remember is (00:44:30) that staphylococcus epidermidis (00:44:32) sometimes when you do what's called (00:44:33) blood cultures (00:44:35) you're taking basically blood and (00:44:37) culturing up for bacteria (00:44:39) and this is one of the most common part (00:44:40) of our skin flora so it is a very common (00:44:43) contaminant (00:44:46) for (00:44:47) blood cultures why is that important (00:44:50) if you go ahead and order some blood (00:44:52) cultures on a patient and it comes back (00:44:54) and it's like oh (00:44:55) staphylococcus epidermidis positive (00:44:57) you'd be like ah that's okay it's a (00:44:58) contaminant of the actual blood culture (00:45:01) from the skin okay so that's a big thing (00:45:03) and usually you know how you treat these (00:45:06) pull the actual device because again (00:45:07) antibiotics aren't going to be super (00:45:08) great it's really just removing the (00:45:10) device and that's going to help with the (00:45:11) actual infection (00:45:13) again because it likes to form biofilms (00:45:14) on catheters you can also get something (00:45:16) called a catheter (00:45:19) associated urinary tract (00:45:22) infections (00:45:23) so what's called a caudi (00:45:25) catheter associated urinary tract (00:45:27) infections because when you put in a (00:45:28) foley and this is a part of that skin (00:45:29) flora gets picked up (00:45:31) leads to a biofilm leads to infection (00:45:33) how do you do it how do you treat it (00:45:35) don't really worry too much about (00:45:36) antibiotics you can get antibiotics but (00:45:37) the big thing is get rid of the catheter (00:45:40) again you're going in you're getting a (00:45:41) prostatic heart valve when you do the (00:45:43) prostatic heart valve some of the actual (00:45:45) bacteria loves to form on that valve it (00:45:47) can lead to a (00:45:49) prosthetic valve so it can lead to (00:45:50) what's called like a a prosthetic (00:45:53) infection a prostatic valve (00:45:57) valve (00:45:59) infection almost like an endocarditis (00:46:02) basically (00:46:03) okay so pretty much like an endocarditis (00:46:04) of the actual prosthetic valves (00:46:07) also if it's on like a prosthetic hip (00:46:09) joint okay maybe like a prosthetic joint (00:46:11) that gets put in and it starts to (00:46:13) actually form some infections around (00:46:14) that actual prosthetic joint you may get (00:46:16) what's called a prosthetic (00:46:18) joint infection as well (00:46:21) okay (00:46:23) and usually it's something as simple as (00:46:25) like having positive blood cultures and (00:46:27) evidence of like an infection (00:46:28) um a fever an infection actually a (00:46:31) representative on like a trans uh (00:46:33) esophageal transthoracic echocardiogram (00:46:35) you see kind of evidence of vegetations (00:46:37) or you have pain you have fever you have (00:46:39) redness over a joint and maybe even like (00:46:41) kind of actually extending (00:46:42) anything from the actual area around (00:46:44) where the prosthetic joint is these (00:46:46) could be kind of identifiers of (00:46:47) staphylococcus epidermidis okay so again (00:46:49) remember these as particular infections (00:46:51) catheter associated infections big big (00:46:53) thing here is the contaminant of blood (00:46:54) cultures caudies prosthetic valve (00:46:56) infections and prosthetic joint (00:46:58) infections next one is staphylococcus (00:47:01) appropriate all right and then the last (00:47:03) type of bacteria here again is a (00:47:05) staphylococcus saprophyticus remember if (00:47:07) it has the ability to travel from the (00:47:09) perineum or through a foley catheter any (00:47:11) way that it can get introduced into the (00:47:13) bladder and start causing infection (00:47:17) of the bladder and potentially even (00:47:19) spread (00:47:20) from the bladder up through the ureter (00:47:23) and then into the kidney it can lead to (00:47:26) urinary tract infection so either way (00:47:28) you can get something called urinary (00:47:30) tract infections utis and this could be (00:47:33) either due to kind of inflammation and (00:47:35) infection of the bladder like cystitis (00:47:37) or it could be inflammation infection of (00:47:39) the actual kidneys and part of the (00:47:41) actual ureters leading to something (00:47:43) called a pyelonephritis but either way (00:47:45) these are categories of urinary tract (00:47:47) infections so that covers the infections (00:47:50) and diseases that we see from these (00:47:51) species the last are these types of (00:47:53) bacteria the last thing that i want to (00:47:55) cover is how do we treat it all right so (00:47:57) now let's talk about the treatment of (00:47:58) staphylococcus aureus and epidermidis (00:48:01) saprophyticus (00:48:02) so (00:48:03) it's very very important for us to (00:48:04) understand another underlying topic with (00:48:07) this which is how antibiotic resistance (00:48:09) comes into play so you know (00:48:10) staphylococcus aureus (00:48:12) originally let's say that you had the (00:48:14) ability to treat it with penicillin (00:48:17) these bacteria are so nasty that they've (00:48:19) just come up with ways to be resistant (00:48:21) against penicillin and then they came up (00:48:23) with another one called methicillin and (00:48:24) it became resistant to that and then we (00:48:26) start treating with something called (00:48:27) vancomycin and it's become resistant to (00:48:29) that (00:48:30) how do we know this whole process let's (00:48:32) go through the ways that it's become (00:48:34) resistant and then we'll talk about the (00:48:35) antibiotics that are treating those (00:48:37) particular like categories of (00:48:39) staphylococcus aureus (00:48:41) all right so the first one is let's say (00:48:43) that we have some staphylococcus aureus (00:48:44) here (00:48:45) and it has the ability to produce an (00:48:47) enzyme called a beta (00:48:49) lactamase (00:48:50) so this beta-lactamase basically will (00:48:53) inhibit any kind of like beta-lactam (00:48:55) particularly (00:48:56) any kind of beta-lactam antibiotics (00:49:00) there's only kind of a couple (00:49:02) antibiotics really um that still have (00:49:05) some effect against this (00:49:07) staphylococcus aureus even though they (00:49:10) have this beta-lactamase presence so (00:49:13) again if the staphylococcus aureus (00:49:15) releases this beta-lactamase it can (00:49:16) inhibit certain beta-lactaman (00:49:18) antibiotics from being effective (00:49:20) this puts this type of staphylococcus (00:49:23) aureus in the category of what's called (00:49:25) it's not resistant to another type of (00:49:27) antibiotic called methicillin it's (00:49:29) sensitive to it it just produces the (00:49:31) betalactomy so we call this methicillin (00:49:34) sensitive staphylococcus aureus also (00:49:36) known as misa (00:49:39) misa (00:49:40) is very sensitive to certain types of (00:49:43) antibiotics like oxicillin (00:49:46) and naphthalene (00:49:49) so these are antibiotics that i can use (00:49:51) to treat (00:49:52) methicillin sensitive staphylococcus (00:49:54) aureus okay and we should try to narrow (00:49:57) our antibiotic spectrum if we can't you (00:49:59) want to try to avoid using broad (00:50:01) spectrum if possible all right so let's (00:50:02) say that the staphylococcus aureus says (00:50:04) okay (00:50:05) i don't want to be you know sensitive to (00:50:06) oxacillin and naphthalene anymore i want (00:50:08) to be a little bit more resistant (00:50:10) okay and so this is where they started (00:50:11) to use like this antibiotic called (00:50:13) methicillin right now they particularly (00:50:14) in like studies and stuff like that to (00:50:16) see if like you know the bacteria to be (00:50:18) sensitive to them and so again utilizing (00:50:21) this methicillin certain types of (00:50:22) staphylococcus bacteria staphylococcus (00:50:25) aureus would be sensitive against the (00:50:27) methicillin and they would you know not (00:50:29) able to still grow okay and that's where (00:50:32) oxaline and naphthalene were effective (00:50:34) but then they started finding that the (00:50:36) bacteria were becoming more resistant to (00:50:38) the methicillin and then air therefore (00:50:39) oxacillin and naphthalene were not good (00:50:41) antibiotics for that anymore (00:50:43) how did it do that (00:50:44) well there's a gene (00:50:46) that the staphylococcus aureus species (00:50:48) start actually kind of developing (00:50:50) and it's called a meca gene (00:50:53) the mech a gene leads to the actual (00:50:55) production (00:50:57) okay the transcription translation of a (00:50:59) very specific type of protein called a (00:51:00) penicillin binding (00:51:02) protein type 2a it's like what the heck (00:51:05) this protein (00:51:07) is different in a way that now (00:51:10) certain types of antibiotics like (00:51:12) methicillin or oxacil and naphthalene (00:51:14) and other things like that are no longer (00:51:17) effective and so it decreases the (00:51:20) efficacy (00:51:23) of (00:51:24) methicillin (00:51:26) and other kind of like similar (00:51:28) antibiotics okay the reason why is it (00:51:31) changes the structure of the penicillin (00:51:33) binding protein that's why it's (00:51:34) penicillin binding protein 2a it changes (00:51:37) the structure of it in a particular way (00:51:39) where methicillin oxacillin naphthalene (00:51:41) other types of beta-lactam antibiotics (00:51:44) aren't able to interact with that (00:51:46) protein you know penicillin binding (00:51:47) protein is a transpeptidase it basically (00:51:50) helps to kind of lift grow our cell wall (00:51:52) if we inhibit the penicillin binding (00:51:54) protein we won't be able to grow the (00:51:56) cell wall we inhibit that (00:51:57) transpeptidation process (00:52:00) the methicillin is no longer able to (00:52:02) exert its effects or oxacillin or nafsil (00:52:04) and other types of penicillin related (00:52:06) antibiotics (00:52:07) and so because of that (00:52:09) its efficacy is diminished and now these (00:52:12) bacteria are resistant to methicillin (00:52:15) oxacil and naphthalene but we like to (00:52:17) put them into a category particularly (00:52:20) specific with methicillin so we call (00:52:22) these bacteria methicillin resistant (00:52:24) staphylococcus aureus or mrsa so i can't (00:52:28) use oxycontin i can't use naphthalene i (00:52:30) can't use amoxicillin i can't use any (00:52:31) kind of penicillin or really a good (00:52:33) beta-lactam antibiotic (00:52:35) so i need to kind of start branching out (00:52:37) and that's where we start getting things (00:52:39) like vancomycin (00:52:41) which is one of those big like drugs (00:52:43) that we hear about all the time utilized (00:52:45) in hospitals like an iv form (00:52:47) this is really good for what's called (00:52:48) your hospital acquired (00:52:51) mrsa because you have two different (00:52:52) types you have your hospital acquired (00:52:53) mrsa (00:52:54) and then you have your community (00:52:56) acquired (00:52:57) mrsa (00:52:58) the vancomycin is really kind of the (00:53:00) best way to treat the hospital acquired (00:53:02) mrsa your community-acquired mrsa (00:53:04) infections those can be better treated (00:53:06) with other types of antibiotics you can (00:53:08) use things like (00:53:09) doxycycline (00:53:12) you can use things like clindamycin (00:53:15) and you can easily use what's called a (00:53:17) trimethoprim sulfa methoxazole tmpsmx (00:53:21) also known as bactrum is the the brand (00:53:24) name these are particular types of (00:53:26) antibiotics that would treat more of the (00:53:28) community-acquired mrsa (00:53:30) and then vancomycin would be better for (00:53:32) your hospital-acquired mrsa okay (00:53:36) so again that's a big big thing to (00:53:38) remember here okay so we have misa we (00:53:40) have mrsa (00:53:42) the bacteria are getting even stronger (00:53:43) man (00:53:44) vancomycin is a really really powerful (00:53:46) antibiotic especially against like (00:53:48) certain types of mrsa species (00:53:51) okay but what if this staphylococcus (00:53:54) aureus (00:53:55) became even more resistant and it does (00:53:59) it says i'm going to make another gene (00:54:01) called a van (00:54:03) a gene (00:54:04) and this van aging is going to alter (00:54:08) the (00:54:09) peptidoglycan cell wall (00:54:12) and i'm going to alter in such a way (00:54:14) where vancomycin (00:54:18) efficacy (00:54:19) is going to drop (00:54:22) significantly (00:54:23) and so vancomycin won't be able to (00:54:25) inhibit the cell wall (00:54:27) process the cell wall synthesis process (00:54:29) anymore i'll be able to survive even (00:54:31) despite the presence of vancomycin (00:54:34) now we have something called vancomycin (00:54:37) resistant staphylococcus aureus so now i (00:54:39) can't use vancomycin anymore i've got to (00:54:42) find other antibiotics to be able to (00:54:44) treat this type of bacteria and there's (00:54:46) a bunch of these (00:54:48) the big one to remember that you're (00:54:49) probably going to want to remember for (00:54:51) like exams is something called lynasolid (00:54:56) okay so don't forget that that covers (00:54:59) the treatment (00:55:01) of the actual staphylococcus aureus (00:55:02) we're try truly trying to understand why (00:55:05) certain antibiotics are best for certain (00:55:07) types of staph species okay particularly (00:55:09) ras (00:55:10) now let's talk about staphylococcus (00:55:12) epidermidis all right so staphylococcus (00:55:14) epidermidis (00:55:16) this is pretty much going to have (00:55:18) somewhat of a similar activity again (00:55:20) that we talked about a staph aureus so (00:55:22) the staphylococcus epidermidis it also (00:55:25) can make an enzyme called the beta (00:55:27) lactamase (00:55:28) so therefore it can inhibit (00:55:30) the beta lactam (00:55:33) antibiotics (00:55:35) and therefore it can be resistant to (00:55:37) certain types of beta-lactam antibiotics (00:55:40) okay (00:55:41) but it's still sensitive to things like (00:55:44) what's similar to oxacel and a naphthone (00:55:46) like methicillin (00:55:48) so (00:55:49) this is technically within the category (00:55:50) of a (00:55:52) methicillin-sensitive (00:55:53) staphylococcus epidermidis so it's (00:55:56) technically what's called a methicillin (00:55:57) sensitive (00:55:58) staphylococcus epidermidis and so you (00:56:01) can treat these types of infections with (00:56:04) oxacillin (00:56:06) and naphthalene (00:56:09) but (00:56:11) if you have this actual (00:56:13) bacteria here develop a way of becoming (00:56:16) somewhat resistant (00:56:19) to the actual methicillin it develops a (00:56:21) resistance to that for example it starts (00:56:24) having these genes called the mec a gene (00:56:27) and that mech a gene starts actually (00:56:29) leading to an increased production of pb (00:56:32) p2a so it changes in the penicillin (00:56:35) binding protein and that decreases the (00:56:39) efficacy we'll just put efficacy of (00:56:42) methicillin (00:56:44) then we can't use things like oxacillin (00:56:46) and naphthalene we have to kind of (00:56:48) change it up a little bit and so we (00:56:50) start having something called (00:56:51) methicillin resistant staphylococcus (00:56:54) epidermidis and this is where we would (00:56:56) have to use something like (00:56:57) vancomycin but remember what i told you (00:57:01) is really kind of one of the easiest (00:57:02) ways to treat this infection (00:57:04) sometimes it's as simple as because it's (00:57:06) an infection of a catheter like a foley (00:57:08) catheter or an infected venous catheter (00:57:11) in certain situations like an infected (00:57:14) like a prosthetic joint or endocarditis (00:57:16) we could use things like oxacil in a nap (00:57:18) cell and vancomycin that would be kind (00:57:19) of worthy of treating like a prosthetic (00:57:21) joint infection or a prosthetic valve (00:57:23) infection (00:57:24) we could use something like oxicel and (00:57:26) nafsil or vancomycin (00:57:28) but if it's something like a a caudi or (00:57:30) if it's like a (00:57:32) catheter associated urinary tract (00:57:33) infection or a vascular infection from a (00:57:36) catheter what do we do (00:57:38) get rid of the device pull the device so (00:57:40) if you remove (00:57:43) the device you technically can remove (00:57:45) the infection because what's the way by (00:57:47) which these types of bacteria really (00:57:49) cause infections biofilms so even trying (00:57:52) to give them antibiotics sometimes (00:57:54) aren't going to be super effective (00:57:55) they're going to be able to evade the (00:57:56) immune system so get rid of the catheter (00:57:58) the foreign device and you remove the (00:58:00) infection (00:58:01) okay (00:58:02) staphylococcus saprophyticus (00:58:06) this guy right here (00:58:09) he's a very interesting one okay when he (00:58:11) produces infections he produces urinary (00:58:13) tract infections (00:58:14) and really there is a very specific (00:58:17) subset of antibiotics that you give to (00:58:19) patients with urinary tract infections (00:58:21) again the most common types of (00:58:23) infections that you see with this is (00:58:25) cystitis (00:58:27) it sometimes can cause staphylococcus (00:58:30) it can sometimes cause pyelonephritis (00:58:32) but you're going to see cystitis is (00:58:33) going to be the most common aspect of (00:58:36) the urinary tract infections with this (00:58:37) bacteria and the first line antibiotics (00:58:40) that you treat with cystitis it's just (00:58:42) the ones that you primarily give (00:58:44) is going to be something called nitro (00:58:48) pharantomine (00:58:49) also known as macrobid (00:58:52) another one is called trimethoprim (00:58:54) sulfamethoxazole (00:58:55) known as bactrum (00:58:57) and then the other one is something (00:58:59) called (00:59:01) phosphomycin so phosphomycin which is (00:59:03) kind of like a one-time (00:59:05) dose (00:59:08) so these are particular types of (00:59:09) antibiotics that you treat (00:59:10) staphylococcus appropriaticus with (00:59:12) usually if it's due to an infection like (00:59:14) a urinary tract infection usually (00:59:16) cystitis (00:59:17) now (00:59:19) if you can't give these for whatever (00:59:21) reason there's a contraindication to (00:59:23) giving them (00:59:24) it's not effective against it for (00:59:25) whatever reason you have other options (00:59:28) that you can reach for (00:59:30) other options that you can treat with (00:59:32) include something like (00:59:35) cephalexin (00:59:36) is a particular type of antibiotic that (00:59:38) you can give (00:59:39) augmentin (00:59:42) is another one as well (00:59:44) these are usually your second line you (00:59:46) usually don't have to use these too (00:59:47) often one is because (00:59:49) cephalexephylexin you have to get that (00:59:51) almost take it four times a day so (00:59:52) there's a decrease in compliance there (00:59:54) but again these are potential (00:59:56) alternatives if there is a (00:59:57) contraindication to these the only other (01:00:00) one that you can mention here is that (01:00:02) there is a potential for ciprofloxacin (01:00:06) but generally we really try to reserve (01:00:09) this one (01:00:10) we try to avoid having to give (01:00:12) ciprofloxacin because there's a lot of (01:00:14) adverse effects with this drug qt (01:00:16) prolongation you have a lot of (01:00:18) interaction with particular drugs with (01:00:20) the cytochrome p450 system and on top of (01:00:23) that the potential of like achilles (01:00:25) tendon rupture (01:00:26) so and there's also lots of resistance (01:00:28) for this drug in certain populations so (01:00:30) ciprofloxacin is really only reserved (01:00:32) for very resistant cases of urinary (01:00:35) tract infections (01:00:36) and that's when you would particularly (01:00:38) give this (01:00:39) so again big thing to remember here (01:00:41) staphylococcus appropriaticus these are (01:00:43) the first line antibiotics these are (01:00:44) your two second line and this is for (01:00:46) more of your resistant cases or chronic (01:00:48) cases of utis all right ninja nerds in (01:00:51) this video we talk about the (01:00:52) staphylococcus bacteria i hope it made (01:00:53) sense i hope that you guys enjoyed it (01:00:55) alright engineers as always until next (01:00:57) time (01:01:02) [Music] (01:01:17) you