hi welcome back to sketchy micro this is Andrew we're going to be covering salmonella and specifically two subspecies of Salmonella Salmonella typhi and Salmonella enteritidis and although these subspecies are very different I think there are enough shared features that it warrants us including them in the same sketch this way we can really clump together the commonalities and then highlight the differences alright so let's get to sketching this out I think the topic for this sketch should be a salmon dinner salmon is a pretty obvious association with salmonella I imagine you guys have at least subconsciously made that association so let's not change it but I think having it be a dinner will allow us to expand more and include more features let's start by drawing a table then on top of the table we'll have our salmon dish a little thing that will include what the salmon is have the tail flopping around just to give action to it so that you remember that salmonella is modal that's a big feature salmonella is modal and as a quick time to this it's also a ch2 us+ you can remember that all enteric bacteria that are modal are also h2s positive which means that it grows black colonies on hecto and auger plate but just to really drill it in we'll go ahead and paint the plate that the fish is on black okay so that black plate should trigger a memory of you know black colonies on the hecto and auger plate which means h2s positive another shared feature between both Salmonella sub species is that they're encapsulated we can represent this by just drawing a glass dome over the salmon dish I like this it kind of looks like what those fancy bakeries used to serve their pastries should be a good reminder the next feature that both share is that their acid labile this is important because if their acid labile they get easily degraded in the stomach so that means that you need a really high dose to cause infection this is opposed to Shigella which isn't acid labile and only needs a few organisms to cause infection so then additionally it would make sense that if you're taking a mep rizal or had pernicious anaemia or had any other conditions that lowered stomach acidity you'd be more susceptible to infection so how do we remember this well a lot of people like lemon with their salmon so we can add a slice of lemon which you would equate with acid and you'll just have to remember that it's acid labile so now it's time to differentiate between the two subspecies of Salmonella over on the left will have Salmonella enteritidis and on the right Salmonella typhi on the left will have a chicken this will remind us that we acquire Salmonella enteritidis by eating undercooked chickens and that chickens are the main reservoir again on the other side of the page we'll have a seagull this is to represent gall bladder I know it's a little more of a stretch but I think you should be okay with it and this is to remind us that chronic carriers of Salmonella typhi Harbor it in their goal bladder let's focus in on salmonella typhi for a bit and also strengthen the connection between Salmonella typhi and the seagull by adding this apron on the seagull this will help remind us of typhoid mary the chef if you haven't heard about typhoid mary i check it out quickly on wikipedia it's somewhat interesting and it might help you remember well add red spots to the apron to represent the Rose spots or red macules that patients with enteric fever get on their abdomen this only happens about 25% of the time but that's enough for it to be testable so you'll want to be able to recognize it one of the important clinical features we have to remember for Salmonella typhi is that it's the number one cause of osteomyelitis in patients with sickle cell disease so we'll go ahead and erase the head of the salmon and expose the bones this should help you remember osteomyelitis then we'll add a sickle to the hand of the seagull and have it looming ominously right above the bone and that should be a strong enough association typhoid fever is generally associated with constipation but it can cause diarrhea and when it does it's said to resemble pea soup so we'll go ahead and draw some bird droppings here the color of pea soup to help remind you of that another difference between salmonella typhi and enter it itis is that typhi is treated with an antibiotic most often a fluoroquinolone so we'll go ahead and draw a flower on the table closest to the seagull to represent fluoroquinolone salmonella typhi also has a live attenuated vaccine will draw the syringe and it will be sticking the leg of the seagull this should remind you that it's Salmonella typhi and not Salmonella enteritidis that has the vaccine all right let's bring our attention back to the chicken the main thing I want you to remember is that Salmonella enteritis causes inflammatory diarrhoea so we'll show you by having the chicken light the candle in this flame will remind you of inflammatory a very Lynch factor for Salmonella that you also see pop up for Shigella and your suniye pestis is that it contains a type 3 secretion system this is a protein that not only detects eukaryotic cells but when it does it secretes a protein that helps with infectivity and unfortunately this is something you'll have to remember we'll draw this turkey baster near the chicken and this will be a symbol for the type 3 secretion system we'll keep reusing it in future drawings and hopefully by then it'll be really fixed we're almost done with the sketch but there is one more point I want to bring up about the pathogenesis of both subtypes so say we do ingest a dose sufficient enough to cause disease what happens is it passes through the stomach through the small intestine into the colon and there it invades the lymphatics it actually gets taken up by macrophages and then carry it into the blood so the important point is that it's facultative intracellular but specifically within macrophages so we're going to draw these bird cages behind both birds and the doors are open so this kind of signifies that they can go in and out of the cages okay that represents facultative intracellular you can remember that it's macrophages because it rhymes with cages or if that doesn't work we'll just write the M Phi symbol on the cages and if you're a visual learner you'll remember it that way and that's all the information we're going to cram into this sketch let's go over it all again one more time first we have the salmon representing salmonella then we have is tail flapping around to remind you that its modal we painted the plate black to remind you of h2s positive and that forms black colonies on hecto and auger plate we have this glass dome representing the capsule and the side of lemons will represent that it's acid labile on the left the chicken will represent Salmonella enteritidis it's also the reservoir on there on the right we have this eagle for Salmonella typhi sea gull for gall bladder which is the reservoir the apron serves a dual purpose it reminds us of typhoid mary the chef and the rose spots seen in typhoid fever the seagulls holding the sickle above the fish bones to remind us of osteomyelitis and sickle cell patients and we have the pea soup droppings for pea soup diarrhea we have the syringe representing the live attenuated vaccine and a flower for fluoroquinolones the turkey baster is the type three secretion system the matches are for inflammatory diarrhoea and the two cages in the back have their doors open to remind us that they're facultative intracellular and macrophages this is our fast recall symbol for salmonella it's red because salmonella is gram negative engrams so upon Gram stain we'll refer back to the symbol and future drawings to group organisms and rhe access your memory of this sketch finally I want to challenge you to think about Salmonella in one week and see how much you remember I'm sure you'll be surprised that's it for Salmonella there is a lot of information but I think is very manageable follow us on Twitter for updates and check us out at WWE TV crew com there you can print up some PDFs to take notes or even add to the sketches and we'll check out your comments on YouTube so that we know we're doing right and what we can improve upon thanks a lot