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Ok. Um Hi, everyone. Um Thanks for joining us today. It's my pleasure to um to introduce Anya. Um Anya um was last year's prize winner for microbiology as well as one of the prize winners for pathology as war. So we've got a really great and experienced lecturer here and whenever you're ready and you feel free to take it away. Great. Thank you. Are you? Um So hi guys today, I'll be going over um the first part of the microbiology content for PAP. Um just to start with a um quick disclaimer. So I'm, I'm only a final year student. I'm not a um infectious diseases expert by any means. So um take whatever I say with a pinch of salt. Um and this isn't, I'm not gonna cover the whole of microbiology in this talk. So I'm gonna be focusing on more of the high yield topics. But if there's anything you want explaining more, if you have any questions, I put my email on the first slide, so you can always email me afterwards. Um I should so a lot of path is also sort of rote learning. So I'll cover the sort of key points of each of the topics, but you'll have the slides to go through in your own time. So I won't sort of bore you by reading out every single thing on, on the slide. So we have a bit more time for questions later, um, and feel free to pop any questions in the chart as we go along. So in terms of what we're covering today, um So these are the topics we'll be covering. I've also got a mentee for some of the questions later. So you can log on with that code, but it'll pop up later when we have the questions. Um So we're gonna start with lower respiratory tract infections. Um So with medicine in general and path included, it's really good if you can sort of classify how you learn things, they particularly in final year, they quite like that as well. So in terms of uh low respiratory tract infections in general anatomically, these are infections affecting the bronchi and more distal structures and impact the mainstay of this will be pneumonias. So infection of the lung, parenchyma and you can think about um pneumonias in terms of the organism that causes them. So these can be typical or atypical for community acquired pneumonias. And you can also classify pneumonias based on how you've got them. So they can be community hospital or ventilator acquired. So, thinking about typical and atypical pneumonias. So this isn't really to do with how common they are, but more about how they present and what you see on chest X ray. So with typical pneumonias, patients are typically septic. So they're unwell and on a chest X ray, you'd see lobar consolidation. So you can see here you the horizontal fissure of the right lung is very uh well demarcated. So that's sort of suggesting an upper lobe pneumonia. And these pneumonias tend to respond well to penicillins. And in contrast, atypical pneumonias typically have a more flu like prodrome and you see extra pulmonary features. So deranged LFT S, you might see lymphopenia or hyponatremia, um, rashes and things like that. And as you can see on this chest X ray, there's often more diffuse shadowing. So it's less focal consolidation and these pneumonias tend to respond to macrolides. So things like Clarithromycin rather than penicillins. Ok. Um And then if we think about what organisms cause these different types of pneumonias. So this is quite a common thing for them to ask you um the typical organisms. So the most common is strep pneumo. Um And the buzzwords for what, what might lead you to this as the answer to a question would be rus colored sputum is what le likes to talk about and you can test for strep pneumo using a urine urinary antigen test and there's one other organism we'll chat about later that you use this for as well. Another common typical organism is Hemophilus influenzae. So this um typically see in people with CO PD and then you also have Moraxella, which is common in smokers and staph aureus. And the buzzwords for these would be someone who's had influenza previously. And if a person has cavitating lesions on chest X ray, that also makes uh staph aureus more likely. And I've put the gram stain and type for all of these organisms, look at those in your own time, but it's good to know what types they are. Um because that can come up quite a bit. Now, if we think about the atypical organisms, there are a few more of these and they have a slightly more different presentation. So, um Klebsiella is classically seen in people who are alcoholics and it's also a common cause of aspiration pneumonia and similar to staph aureus. It can form cavitating lesions and a person might have hemoptysis alongside this. Um Chlamydia pneumonia is another atypical organism. It's a bit less common, seen more often in Children and then you get legionella. This is a common one they like uh to ask you about and it's classically after some sort of exposure to water sources. So this could be for plumbers or someone who's been on, on holiday and they've uh been exposed to air conditioning. And the classic extrapulmonary features for legionella are hyponatremia typically alongside Duran LFT S and lymphopenia. And this is the other organism you use a urine test to identify. Um and then you can also have mycoplasma again, often seen more commonly in younger people. And the classic extra pulmonary features here are a called autoimmune hemolytic anemia. So, if you see a patient with a pneumonia and they've got raised bilirubin, then think about mycoplasma and also a typical um erythema multiform rash. Um Other features you'd see with this and then two slightly less common um atypical organisms would be chlamydia and Coxiella and these are typically after animal exposure. So for chlamydia, this will be exotic birds and for Coxiella, farm animals and both of these can also cause something called culture negative endocarditis. But we'll talk about that in more detail later on in this talk. And then in terms of um immunocompromised patients, there are um typical organisms which affect people who are immunocompromised. So, in patients with HIV Pneumocystis pneumonia is the um classic organism you'll hear talk, it talks about and this classically presents with desaturation on walking. So if you um see a patient and they say that oh, their SATS are 96%. But when they walk for a bit, it's 88 or something that's typical of PCP. And you would treat this with cotrimoxazole. It's important to remember that Cotrimoxazole has trimethoprim in it. So if a patient has a contraindication to trimethoprim, then they'll also have a contraindication to cotrimoxazole. Um and then for people who've had a splenectomy, um they more commonly get pneumonias caused by an encapsulated organisms. So these are the NHS organisms. Um Neisseria, meningitis, Hemophilus, influenzae and strep pneumo again. And these patients for that reason are often on penicillin v to protect against these organisms. Patients with cystic fibrosis, um classically get pneumonia caused by pseudomonas. Um but cold diarrhea. Um So if the patient has pseudomonas and they've got cystic fibrosis, you try to eradicate it and these are the five antipseudomonal drugs. I'd recommend learning these. Um, just for life in general, it is quite useful. When you see a patient on one of these antibiotics, you can think that, oh, maybe they've got a pseud infection. Why? Why would they have a seed infection? So they're useful to learn. Um and bur cold area is clinically relevant because um this will be contraindication for a patient having a lung transplant. Um So it's important to identify and in patients who are neutropenic, they're more um predisposed to infection by Aspergillus and their um their classic buzzword for this is if you see a halo sign on CT, that's suggestive of um an Aspergillus infection. Ok. And then in terms of managing community acquired pneumonias, um you'll probably have learned this in third year, but you um classify severity of pneumonia using 65 scores and these are the different components um based on the score patient has, you know how to treat it. So, if it's a mild um infection, you can use amoxicillin alone as an outpatient, if it's moderate So a score of two, you would use amoxicillin and a macrolide most commonly Clarithromycin. And you can consider admitting them and if it's three or above, they need IV uh Coamoxiclav, most likely Clarithromycin, and you would definitely admit them and consider intensive care input. Um I would just put as an aside here. If a patient has M RSA, then the first line anti M RSA agent would be Vancomycin. Um And if a patient has a pseudomonas infection, you should use tazocin to start with in terms of hospital acquired pneumonias, the kind of organisms which cause these are again a bit different. So, the most common organisms for hospital acquired pneumonias are staph aureus, pseud pneumonia. Um and these um enterobacteria, um again, more commonly because patients often get, um, can aspirate as well. So you see these, uh more commonly and the management for these infections.