Staphylococcus: Aureus, Epidermidis, Saprophyticus

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

Channel: Ninja Nerd

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Keywords: Ninja Nerd Lectures, Ninja Nerd, Ninja Nerd Science, education, whiteboard lectures, medicine, science

Id: 6BkqWKOG8E0

Length: 61min 18sec (3678 seconds)

Published: Thu Oct 21 2021