Things you need to know about Microbiology

Primary Care Knowledge Boost. Things you need to know about microbiology in general practice. Music.

Welcome to Primary Care Knowledge Boost. I'm Dr Sarah McDermott.

And I'm Dr Lisa Adams. And we're here today with Dr Callum Mutch, who is a consultant microbiologist and infectious diseases doctor up in Scotland for his take on things that we need to know in general practice around microbiology and antibiotics yes exactly Callum is also the co-host of a very good podcast with a fellow doctor and their podcast is brilliant you should check out we'll put a link in the episode description he speaks to us about what we need to know in general practice about what

the microbiologists do so this episode is a bit more focused on antibiotics and we give two cases as a bit of a start and to kind of frame the rest of the discussion he goes through his approach to choosing antibiotics and gives a couple of really good frameworks that you can use to think about what you might need to do and he goes through antibiotic classes and kind of gives a bit of an overview about where antibiotics sit and why it's important to think

about them in terms of classes and why you may need to do that and then talks a little bit about antibiotic resistance. It was great this episode and he's back with us for another one about swabs and collections and urine samples and throat swabs, which is enlightening. So yeah, enjoy these and we'll be back at the end to share our learning points.

Hello, so my name is Carl Mutch. I'm an infection specialist working in Edinburgh. So I've just recently been appointed to a consultant post in both medical microbiology and infectious diseases. And I co-host with my colleague Jane McRae a podcast called The Infectious Diseases Insights of Two Specialists Podcasts or The Idiots Podcast which is very enjoyable with a focus on. Infection trainees education but there's also a lot of stuff there that would be relevant to your.

Audience and hopefully although we may be good on some rabbit holes sometimes and I guess just generally I've got an interest in education I've done a sort of master's in medical education and some other things like that so I obviously listened to your podcast and particularly found the recurrent UTI episode quite useful when you spoke to one of the urologists so thanks for that no he was brilliant yeah that was a really good one that was

a good one I forgot about that that's blast from the past um no it's lovely to meet you Callum and um yeah we've enjoyed your podcast as well so it's quite nice to to link up um and be able to share our mutual interests it was really hard trying to decide what to record because a lot of the things that we come across are going to be like scattered in our day job and so we thought we'd approach it as um just giving you some examples of cases that we see and

and how they what they look like and then just zooming right back and then just going through antibiotics and prescribing um so yeah if we just indulge indulge us in telling you some of our lovely stories for general practice yeah um so um so we've got mary she's 70 and she's got a background of recurrent utis and she had a cystoscopy two years ago and that was clear and the urologist at that point put her on prophylactic low dose nitrofurantoin for six months and discharged her we've started

vaginal oestrogens before she saw the urologist um we saw her last year and we discussed stopping the antibiotics but she was adamant she didn't want to stop them i think we talked about this a bit in the recurrent utis episode as well actually because it's quite a common.

Common issue um they were swapped to low dose cathalexin at one point and she has had another uti in the meantime because we're quite far on in her journey now but her last UTI was over six months ago so we're just a little bit not quite sure where to go with Mary and then I'll tell you about Steve and so Steve's another quite classic case he's a 45 year old man and he has a past medical history of depression and hypertension he comes into the

practice with pain and swelling on the left side of his scrotum he doesn't have any lower lower urinary tract symptoms he's had no new partners no penile discharge and he's had an STI screen a few years ago and he said he's had no new partner since that screen. On examination we want to treat him for epididymitis and the guidelines deofloxacin is first line. He goes to five different pharmacies and he cannot find this anywhere and so we end up having to give him Cipro.

So yeah just another very classic annoyance I would say probably in general practice and takes up quite a lot of admin time for both us and patients.

So yeah I guess if we maybe start then, as Sarah said, with a bit of a zoom out and just ask you generally quite broadly to tell us about antibiotics, what you want us to know. Yeah, these are two challenging cases. And I think it's funny because I see a lot of patients with infection, obviously, but In each specialty, we'll see patients presenting with infection.

You know, everybody deals with infection, but one of the privileges of our role is that we get to interact with pretty much every specialty, both in the community and in secondary care. And so I guess firstly is that, you know, these sort of complex patients presenting to primary practice, sometimes we don't really see them in secondary care as an infection specialist. So sometimes GPs are phoning asking for advice and you're thinking, I don't actually really see this that much.

You've probably seen more of this than me. and guidelines often say, you know, go to, you know, speech-year infection specialist and when you're at the other end of the guideline, sometimes that's quite challenging.

I guess, you know, we've all been to medical school and gone to a lecture about antibiotics and it's probably been quite dry and there's probably been a lot of discussion about classes of antibiotic and, you know, going through that in a lot of detail and, you know, memorising all these names.

But I don't know if that is that like practically useful you know it's like you know patient come and says I've got an infection I was like well careful nexin is a careful spore in antibiotics first generation you know it's not useful knowledge is it so you know I guess we can think about antibiotics in classes because it might help us find similarities between them and say you know this antibiotic is the same class as that antibiotic therefore it might have some similarities

but I don't know if that's the most useful thing to think about I guess when you're choosing an antibiotic, the way I quite like thinking about this, and I don't actually know where this infographic came from, but I guess when we're thinking about which antibiotic to choose, you can think about it in three main groups of factors. So, microbe factors. So, that's things to do with the infection itself. So, first couple of questions there would be, is there actually an infection?

So, both these patients, I guess, the first one probably isn't an infection anymore, and then the second one there probably is we can think about the site of infection um so in this case we're talking about urinary tract infections we might think about antimicrobial resistance.

Antibiograms so you know we um might get a report back from the laboratory which tells us you know it's resistant to this or that and that's obviously going to be the the most useful thing but when you're treating empirically like the second case you don't have that so then you might be thinking about things like what's the typical antibiogram in our area what's the epidemiology so i guess in Manchester, the antibiogram of organisms, so the typical resistance pattern,

will be different from Edinburgh. And so your local guidelines should be taking that into account. And then we can think about, you know, is it bacterial, viral, fungal? You know, a lot of patients are presenting, asking for antibiotics for non-bacterial infections. So that's the microbe factors. Then there's a sort of host factors. So these are really complicated bits. You know, the guideline says use amoxicillin, but, you know, maybe the patient's got an allergy.

You might be thinking about the severity of the infection. So, you know, they've got pyelonephritis, have they just got UTI? Have they got epididymal orchitis, like the second case maybe does? Or do they have something more complex? And then other host factors, so their immune status, are they immune compromised, allergies.

Renal function, liver function, have they got an oral route, what's their other past medical history, what other antibiotics have they had recently, what's their compliance like, how many people can actually take a tablet four times a day? You know, come on, I find that hard. Very hard. And are they pregnant or breastfeeding? And then finally, we might think about the drug factors themselves.

So there's loads of things to talk about here so you know the root how by available is it does it get absorbed you know what the dosing you're going to use so the bnf often lists a big range so keflex is a good example huge range range of dose how do you pick a dose other things you know duration of therapy another pharmacokinetic and pharmacodynamic factors so tissue penetrance does it actually get to the site of action so an example there

might be something like phosphomycin it gets well into the urinary tract but it's not going to treat a chest infection because it just doesn't get there like it might kill the bugs in the lab but it won't actually work and then risks i guess so things like interaction so particularly p450 induction um side effects and then risks of c diff. So it's quite a lot of things. I'm sorry, I've been through that quite rapidly. I'm going to pause there.

Get some thoughts from yourselves. Yeah, I really like that. I don't think I've ever seen it later. I've liked that before. No. Have you said it? No. It's funny when you're making these decisions, sometimes you feel like you're a little bit like a computer just trying to process loads of stuff. And when you actually say it out loud, there's quite a lot going on in your head. There's a lot, yeah. Yeah.

And also there's many things to remember as well. So never to forget things like tissue penetrance or kidney function, things like that. So yeah, it's a great way of looking at it. And yeah, there's so much to process. That's a great start. It is. And I've also never heard the term antibiogram before. That's why I heard that down. I really like that. Antibiogram. Yeah, so there'll be different resistance patterns. Yeah, yeah, exactly.

So, you know, every trust or health board will have an antimicrobial management team and they'll collect data on the resistance patterns of the organisms from the laboratory and then that'll guide their empirical antimicrobial therapy. And I guess it's worth saying that I've made that seem very complicated. In the vast majority of patients, antibiotic prescribing decisions should be quite straightforward, you know, because you've got an antimicrobial guideline.

And I guess what you're really thinking in your sort of pattern recognition type 1 thinking is, is there any reason why I just can't do what I normally do? You know, a patient presents a VUTI, whatever your antibiotic first line is, you know, I think locally it's nitrofurantoin at the moment.

Um you know why can't i use nitrofurin tone that's essentially your thinking isn't it so this what i've just laid out there is where you're getting a bit more complicated there is one of those factors there that means that you you can't use just what's recommended and um or maybe and maybe i should have put this in the drug factors as access isn't it yes yeah it's actually available yeah true um that's yeah that's what i thought i'd throw in the the last case yeah it's

all very me well me saying on you know the end of a phone to gp you know like give them lonezolid but you know these sort of unusual antibiotics you know which pharmacy stops them and and your patient you know if you think you need an antibiotic you should be trying to get that quite quickly yeah and um that's not helpful advice sometimes it's nice to recognize that.

Is it worth going back to the cases yeah and just getting your thoughts yeah well maybe we could approach these cases through that lens i've just given you of the sort of the microbe factors the host factors and the drug factors because to be honest i um obviously think about this a lot and um i think a lot of this is in my head anyway in a sort of pattern recognition state but i sometimes do come back to this just to make sure i'm not missing anything

particularly in complex cases fab so yeah why don't we talk about mary again um and kind of take a look at it like you said through this um lens so just to remind listeners mary was the seven-year-old lady with the recurrent utis and she really didn't want to stop her um prophylactic antibiotics, and when we did swap to kefalexin she did have another urine infection so i guess in this case is our question should we stop it should we go back to nitro yeah and yeah where do

we go from here really we often see these patients where there's not been a huge plan um so very it's very dependent there might be a plan for a certain amount of time but follow up at the moment with with the way the system works is that people just aren't getting follow-up so it's often sort of left to us in general practice to work out what to do. How would you approach this? What are you thinking? What things might be useful from your perspective for us, maybe?

Yeah, I don't think this is a straightforward case. So it's a good one to talk about. You know, I guess if we think through the factors, so microbe factors, the first thing I said, is there an actual, is there infection?

And, you know, this is a lady who's obviously had significant problems with UTIs and got to extent where she's on prophylactic antibiotics so probably right now there's not an infection but you know you can understand the decision making that's been made there's been a risk identified and you know we do have guidelines around you know recurrent UTI and obviously that was that episode that you talked about and there's lots

of other factors you know she's already on topical estrogen and she may well have tried things like methenamine already and you know other sort of avoidance of recurrent UTI approaches that we can take.

My understanding is the guidelines suggest that we should just use, if you're going to use a prophylactic antibiotic user for six months, the theory being that once you have recurrent episodes of UTI, sometimes this, isn't really recurrent so it's not gone away and come back it's just um is it recrudescence i think is a term for when it's like not completely gone or relapse so you know the idea you get this sort of chronic inflammatory state and the

infection never really resolves and so you give a longer course of antibiotics to get rid of it and beyond six months we don't really know.

And you know utis predominantly affect women and it's an under-researched area probably because of that so i guess there's not really that much data to guide what exactly we should be doing with, prophylactic antibiotics in general you know i guess the choice of keflexin presumably she's had these recurrent utis we've looked back at the organisms we can see what the antibiogram is so now that six months of keflexin are up i think um the host factors you know what what

else is going on with her other past medical history both these drugs have have risks and that's something that we would think about in the drug factors so if we just start with nitrofurone first because i I think that's simpler. So the main risk is sort of tissue fibrosis, so retroperitoneal fibrosis and longer term use.

It's a generally, you know, extremely well tolerated drug that because of the way it works and the tissue penetrance, you know, it basically concentrates into urinary tract and is just there. So it doesn't really treat anything else, just cystitis, really uncomplicated UTI, but it does have this rare and very serious risk. And when you see patients with this, I think it really makes you think twice about using dichofuriental in longer term. I've never seen.

No, I've heard. Yeah, I heard. I think I went to a talk where they were saying that fibrosis, lung fibrosis, we should be counselling patients on if they're on it prophylactically, which we're not normally the ones to start it. And I don't know how well that's being done, but I haven't seen retroperitoneal fibrosis. What's the story there?

I don't remember the mechanism off the top of my head, but essentially you just get this sort of irreversible fibrosis which can lead to sort of organ restriction and lots of other side effects and an extremely, you know, severe and life-changing diagnosis. So... I guess for that reason, we're very reluctant to use longer-term courses of that. And then kephalexin, I guess it's a first-generation kephalosporin.

Historically, maybe we've talked about antibiotics and C. diff risk, which was one of our drug factors and thought the kephalosporins were higher risk. Kephalexin probably isn't that high risk an antibiotic for C. Diff in general, but still, I guess, like diarrhea, GI upset are the main risks.

And the other issue with any prophylactic antibiotic is, you know we talk about resistance and you know so you're exposing a patient to this they're going to become colonized and develop resistance and so some of the bacteria in their microbiome will become resistant to these antibiotics so you're sort of just selecting that out, all these things have to be balanced i guess with the host factors you know this is going to be a patient-led decision and it's

very hard when someone's establishing something and it's working for them to say now we're going to stop this because well you know it's worked for me so why should I stop it I feel well and I don't think that's easy and I guess it's just about being really clear about what the pros and cons are about each decision and you know sometimes people can stay on prophylaxis for longer than six months because that's actually the best thing for them,

you know I guess one approach might be saying we can stop it and if you get problems then we can we can always go back to it but the reasons for stopping it would be x y and z so you know side effects and resistance and also you probably just don't need it because most people after six months and you stop, they won't come back. But yeah, not an area where we've got a clear randomized control trial to say,

you know, this is the definite right thing to do. And this is the sort of, I guess complexity of medicine that's really challenging isn't it it's it's easy when there's a there's a clear right answer um and when there isn't like this um I guess all you can do is try and make a decision in conjunction of the patient that they're going to be happy with yeah sounds fairly sensible doesn't it and probably what most gps are doing yeah but it's I think that's really useful to to talk about

the risks and some of those sort of rarer things and yeah I don't know how good all of us are including myself i like to try and zoom out so it's not just me but about keeping up to date with all of the risks and how to then convey those risks that's chance so the bnf and you know you read the on medicines.org the smc the product information for for antibiotic you know it can be a really useful place to go to but i find that's a bit overwhelming and it's

difficult to actually translate that into a conversation you can have of a patient you know you can say like go and read the patient information leaflet here's the link and then they come back and say oh i actually don't want to take this drug because i read this and i'm terrified you know is that actually helpful and um you know so one thing you know i guess i. Prescribe antibiotics and and have these conversations regularly and

i guess my approach is to have things that i you know i talked you know we're told that we have to tell patients about the common side effects and and the sort of rare serious uncommon side effects and so I guess those are probably the most important ones to counsel people from a consent point of view the best thing that I found was I think it was Public Health Wales have published some antimicrobial counseling documents and I thought they were really

helpful because they displayed them in a way that I read and I thought this is basically how I do it and this is a conversation I could easily have with the patient and, And, you know, all drugs have risks. And have you heard of the sort of BRAM framework? Is there any like consent discussion talk about like the benefit, the risks, the alternatives and then nothing. So what happens if you do nothing? I quite like that way of doing it. It's up in our outpatient department.

I don't know who came up with it. I think it's in maternity now and I can't remember what the acronym is. Okay. That they tell you, your midwife tells you. Oh goodness, I'm going to have to think about what that is. It's longer than that though because there's a couple of other letters. And it is to tell patients to ask all those things if they're being asked to make a decision about something to cover it all. I'll think about what it is.

It's making me think of our HRT discussions, a lot of discussions around HRT. And this is the framework I'm subconsciously using, I think, is that. Yeah, my partner's a GP, so I don't really have those discussions. But I hear about those discussions, so this is not very challenging because obviously that's not an easy thing to navigate.

But I think for antibiotics, you know obviously the benefits are quite clear and patients want antibiotics but you know sometimes doing nothing isn't is an option you know we know that a lot of people with a UTI will get better without treatment so I certainly I think I'd want antibiotics if I had urinary symptoms but um uh you know so so there are always um options and alternatives as well that is a good one because I

think if early on in sort of a simple straightforward uncomplicated UTI is there you know, you can use things like ibuprofen. And if it's just a niggle, that's a great thing to kind of nip it in the bud early on. But yeah, it's, it's rare that I'm having that conversation with anyone because normally it's, it's way past that. I often think in medicine, like when we make decisions, it sometimes can be hard to, to like understand, like, is this a straightforward decision that I just do X?

You know, this is the situation, so I will just act because it's simple. Or is this something that like, I need to go and look at a guideline? Or is there just, there's no clear right answer.

And because, you know, evidence is constantly evolving and it's very hard to keep on top of everything that's going on, it can sometimes be hard to know what, section you're in there's this thing that in sort of leadership and management people talk about called the kynethan framework um i don't know why i'm referencing so much welsh stuff but they seem to be doing some great stuff so um it's a a welsh guy kynethan like c-y-n-e-f-i-n and he

came up with this framework for when you were dealing with management and like kind of person like leadership problems and divided things into simple complicated complex and chaos and then how you approach it And I was thinking about that in clinical decision making because, you know, some things are simple, like, you know, a 26-year-old female with a urinary tract infection. It's her first episode. You know, you don't have any positive microbiology. She's got no other health problems.

You just give her, you know, whatever the first line antibody is and that's it done.

Complicated might be like you know the same patient but they're pregnant and they've got penicillin allergy so there is still a right answer to do because your guidelines should provide data for that and you know you can go to a source and then a complex problem might be the same patient but actually they don't want to take antibiotic x you know the first line recommended one because they've had bad side effects from it before and there's

there's some other sort of patient factor um that's that's leading it you know they've got some past medical history with sort of you know maybe they've got um what's myosinia gravis oh yeah so maybe they've got myosinia gravis as well you know this is like the heart sync patients that i get when someone phones up and they say they've got someone who's pregnant and they've got a penicillin allergy and they've got myosinia gravis and i'm so like oh god so that's you know complex because you

don't know how helpful it is just picking up the phone and saying that's someone else there yeah yeah exactly sharing that burden of decision making but like that complex problem there isn't there isn't like nobody's ever done a trial in that situation there isn't actually a right answer.

Simple problems are like you just do the thing complicated problems there is best practice you know you go to your gp.book or bmj best practice or something you know there's a clear there will be an answer you just need to find it out complex there probably isn't a right answer you're going to have to come up with something and everything will have risks so it's just a balance yeah and then chaos is chaos you know everybody knows chaos is that sometimes that

you know gp practice on a friday afternoon but um yeah so i i think that that can be quite helpful because if you don't know which of those sections you're in then you maybe have a problem like if you think a problem is complex because you don't think there's guidance but there is that's that's an issue isn't it and if you're making simple problems complicated that's not going to be efficient so um i sometimes i'm stuck kind

of trying like what actually watch bracket my in and if i'm in complex it kind of.

You know that that uncertainty of decision making can be really hard to sit with but if you then realize there isn't a right answer then that can actually kind of free you to just do what you think is best agreed i think it's the recognition of that yeah allows you to then be able to kind of almost let it go um and think okay well i can just make the best decision i can make it's not if i'm going rogue yeah yeah that's nice yeah i'm not sure how much that has to do with antibiotics but you

know i guess just trying to coach like yeah decisions about antibiotics just like any a decision in healthcare and um sometimes i find that the more i learn about antibiotics it doesn't actually make it more straightforward it's just sort of additional layers of complexity are added on top but yeah but i think knowing like normalizing that and thinking about it pragmatically is a wonderful thing yeah we're in the real world unfortunately yes people aren't like the

books yeah no um should we talk about steve so he's the gentleman with the possible epididymitis that we wanted to prescribe afloxacin so actually using your guideline um or your um sorry not yours.

Using your advice around the framework we can sort of categorize him a bit more he's got um he's probably fairly straightforward but the situation in which he finds himself running around different pharmacies isn't there was a straightforward answer i don't know would you put I mean, complicated? Yeah, no. Or complex? Oh, this is, I'm already struggling with it. Yeah, it does. So you can, you Google the framework and it's got a nice picture and I find that quite useful.

It gives you a sort of framework and there's a lot more about it than I've explained. But, you know, I think this sort of problem, you know, a simple thing would be, oh, you've got a clear diagnosis and there's no other, there's nothing else going on. Yeah. You know, I guess here you've got somebody who's middle-aged and they've got epididymitis. Yeah, so... And we've got clear guidelines for that, but you haven't been able to access the drug that's first line and he's getting ciprofloxacin.

I guess how I think about antibiotics, in addition to what we've talked about there, so we said in the micro factors, you know, is it bacterial, the resistance antibiogram. Jamie and I did an episode on choosing an antimicrobial, which is probably one of the ones that's more useful for your audience than a lot of our ones on, you know, sort of intricacies of lab tests and microorganisms.

And in that, I'll try and just summarise that very quickly, but essentially thinking about what bacteria cause these infections and then which antibiotics treat those bacteria and what's the sort of spectrum of activity, which is sometimes hard to look up, but I can share some sort of basic approaches to that.

So epididymitis, the reason why ophloxacin is first line in our guidelines is because most patients presenting with epididymitis, you know, you want to think about sexually transmitted infections and novoxacin is great because it's a quinolone antibiotic it gets intracellularly it will treat things like comedia it'll treat gonorrhea it's a broad coverage it also treats gram negatives the main cause of utis so when i think about antibiotics i think like i draw a little table which

is like um divides into four quadrants and it's like gram positive cocci gram positive bacilli gram negative cocci gram negative bacilli and then i think okay which are the bacteria that causes this infection so you know epididymitis we might have like Neisseria gonorrhea and our gram-negative cocci we have a chamedia which is doesn't really gram because it's so small and dracellularly and then we think about gram negatives so like E.

Coli and other things in the urinary tract which are clear pathogens and then there's other small.

Print stuff and then when you get into the situation where you're like okay well I can't give the ofloxacin they're on set for floxacin is that okay um and actually it probably is fine it's not as good cover for some of these organisms but it's going to be reasonable and and i mean the key thing here is that you know you've kind of gone into a bit of a complicated realm because the diagnosis isn't particularly clear you know if

the patient had come in and said yeah i had unprotected sex two days ago and now i've got these symptoms i think you know like okay well you know we can link but actually there's not really a clear reason why this patient has got.

Epididymitis yeah so you know that's immediately making me think like I've got the diagnosis right is it an unusual organism you know does it need imaging these sort of questions about other differentials I guess yeah yeah, I guess it's all very well good me saying I draw this chart and think about the bacteria and which antibiotics cover them.

That's something that's quite hard. Somebody on the ward, like a junior member of the team asked me the other day, it's like, how do you learn about antibiotics? It's quite difficult because there's hundreds of them and all slightly different and they cover different things.

It's a great question. Yeah. When we first started training, one of the consultants gave us this like table and it was all a list of antibiotics and then on the columns it was like all these different facts about them and you had to go away and read them up and write them down oh my goodness and it was intense but it was like a really good way to start because you know kind of you have to start at the basics don't you and work your way up and a lot of the time we're in that sort of type one

fast pattern recognition thinking isn't it but when you get outside of that you know immediacy of of action you know that's where it gets really tricky well it's useful i think just understanding why the guideline says of floxin and that you know you're covering those two things is actually quite useful the guidelines we have always have like alternatives so we can normally try and pick from there but it's just kind of why are the guidelines like that it's quite useful yeah exactly and they're

just they're you know the people that are writing the guidelines that you know if you're like writing local guidelines so you know you can look to like nice guidelines or the clinical knowledge summaries or there might be an international guideline and they will be giving you a set of recommendations which you then locally will be taking and saying okay well this is the situation in manchester you know we've got um a much higher rate of

resistance in our you know e coli to things like keflex and so actually we're not going to recommend that first line because there's just so much resistance around in manchester which which there is so yeah so the local the local guidelines will be um probably more focused for your individual.

Patient yeah yes so they're yeah kind of first line to go to and you can also look wider for um more general recommendations um that's sensible did you want to ask some more about kefs yeah just while we're on when i started writing the questions i was i was just kind of highlighting times when these things have sort of cropped up in practice or in teaching and there was a thing about meningitis so they've recently changed what we do if we get an acute meningitis and meningococcal disease

so if we see the petechial rash and a fever and yeah you're jabbing with ben pen but they've said actually keftriaxone they said is actually better if you've got it so the ambulance matters more um but um so do not delay admission but if you could stock your trolley with keftriaxone that would be better just in terms of the coverage i don't know that that's necessarily something we need i can very briefly dodge it if you're interested in the

quite interesting yeah because it's like where do we really need to change do we because that's a real faff and we've learned like to you know laminated things or it's like when you're drawing it up in the in the moment and you're probably really shaky and you need just something really obvious to tell you what what the answer is like how many mils quick ah um yeah i think when you see people with naseria meningitis you know um bacteremia and systemic infection or meningitis that you know is

there extremely sick patients they're deteriorating in a matter of minutes in front of your eye. The rash is spreading very quickly. So obviously, the quicker we can give these patients effective antibiotics, the better. That said, it's a very rare infection. We were talking recently that we see in Edinburgh more cases of malaria than we see of Neisseria meningitis. Wow. Which maybe you wouldn't think, but obviously, you know, there's a lot of people traveling.

And we had an episode recently, we talked to Fiona McGill, who was the lead author of the UK guidelines on meningitis, which was really useful. And she obviously knows a lot more about this than me. But one thing we were talking about was the changing epidemiology of meningitis in general and how Neisseria meningitis has become a lot less common with the introduction of routine vaccination and part of childhood schedule.

Fingers crossed that continues yes exactly we still see it but it's much less common and we always know we have this like idea in our head of this patient who's you know meningitic or they've got fever and headache and confusion and they've got a particular upper period crash but actually look at the patients that have those rashes um you know other organisms so strep pneumo the other main cause of meningitis can also cause that rash so it's not that really

it's not pathognomic so much now because it's so much rarer so my understanding is the move to keftraxone is that actually benzyl penicillin should cover or which you know the penicillin should cover this area but if you use keftraxone then you've got a broader spectrum of coverage and also you know just there's some farm kinetic stuff about you know it's got a longer half life it's just a better antibiotic so we use benzyl penicillin as a step-down agent for

meningitis but we wouldn't use it empirically just because there can be resistance and so on so so yeah i guess the most important thing is getting the patient to hospital very promptly so they can get necessary investigations you know get diagnosis etc but the caveat to that at the moment is that ambulance waits are extremely long and so you know you actually i guess geftraxone would be better benzopenicillin is our penicillin is probably good, so if you can give anything that's great.

We're in a setting where every section of the NHS is stretched isn't it yeah, No, that's really useful to go through the whys and why these decisions are made. Yeah, I'm not making these decisions, so that's my understanding. Hopefully I've got that right.

It's insensible. I'll go with it. The other thing I wanted to ask you is just the general thinking, swaying away from fluoroquinolones. That's the ofloxacin, ciprofloxacin. Yeah, exactly. I could talk through very briefly classes on antibiotics. Just to give us a little ground. Yeah, exactly. and then I'll talk about that in general. A little bit of revision is always a good thing. You love a bit of knowledge there.

So my colleague, James, coined this phrase and I think it's great, which is beta-lactams are best lactams. So we talk a lot about penicillin allergy and using beta-lactam antibiotics. So those are probably our biggest group of antibiotics that feature the most heavily in our guidelines. So beta-lactam is the sort of like ring that's the basis. And within that group, I guess you've got things like penicillins, such as your like penicillin, obviously.

Amoxicillin fluoxicillin you know coamoxiclav pifnosicillinam etc and then as you go up the beta-lactams you now get into cephalosporins such things like your, cephalexin which is probably the only one really that we're using in primary care there are other oral cephalosporins that might be used and things like Keftrax are used a lot in OPATs, OPATs oh sorry outpatient antibiotic teams so that's like once daily IVs like

ampereic care Yeah, hospital at home. Yeah, hospital at home and stuff like that. And then further on, the beta-lactams, you've got things like harbopenem, so your meropenem, hertopenem, very broad spectrum. And then finally things like monobactams, which is astreanam, which you've probably never heard of and you don't need to think about ever again. Good. So...

And a general rule of thumb, which isn't completely, you know, as you grow up the beta-lactams, they get more gram-negative cover, and they're not so good at gram-positives. So if you think of penicillin to amoxicillin, the main change there is amoxicillin's got more gram-negative coverage, so it's a bit broader spectrum.

Um it doesn't always hold true because flucoxacillin as opposed to benzoyl penicillin it's it's formulated in a way that it um is resistant to breakdown by staphylococcus aureus so flucoxacillin is our sort of staphylococcus aureus antibiotic but you know generally speaking as you go up so meropenem has got really broad gram negative cover but it's not really as probably as good as gram positive cover as some of the the earlier antibiotics so it's not necessarily, you know, broader isn't better,

you know, so it's, you know, choosing it right antibiotic for that patient and that bug. So that's your beta-lactams. I guess other common ones are tetracyclines. So everybody loves doxycycline and they've got tetracyclines and, you know, there are other ones that are used rarely, but you don't really need to know about them.

And they are, you know, inhibiting protein synthesis. So whereas the beta-lactams are stopping the cell wall of the bacteria and sort of breaking them down that way and killing the bacteria doxycycline is inhibiting protein synthesis and within that group macrolides are working the same way so your glyphromycin azithromycin eryphromycin and then you've got, lyncosamides which also inhibit protein synthesis so that's things like clindamycin

which is kind of similarly related to macrolides and then we've got aminoglycosides so things like gentamicin which also inhibit protein synthesis. Now these all have some similarities in how they work. So if we start with tetracyclines in our sort of protein synthesis brackets, they're really great antibiotics because they're broad coverage. They've got gram positive and negative coverage, but they also cover what we kind of talk about atypicals, like atypical pneumonia.

So the reason I call it atypical is because they're not really typical bacteria. A lot of these things lack a cell wall. So things like mycoplasma and chlamydofla. So these are really, really small bacteria. Are they really bacteria?

Yes probably they are but um they're very small they live inside the cell and uh they don't gram so you know like when you do your staining in the lab you don't you don't see them because they're inside the the human cells they're hiding they're hiding yeah so to kill these atypicals we want to use antibiotics that get into the cell well and also we would expect that cell wall.

Acting antibiotics wouldn't work against them so our beta-lactams aren't going to work against very typical so that's why i often see guidance which is like if you think about atypical pneumonia, add in you know for example doxycycline or a macrolide so they also work they're very good at getting inside cells they concentrate inside cells and they work on protein synthesis not the cell wall i think that's why our guidelines say for us for um low

respiratory tract infections you go for doxycycline first rather than amoxicillin and you still see amoxicillin prescribed really commonly and it's it's very well tolerated um whereas some people there's more people that get a few more gi side effects from doxycycline but yeah that makes sense yeah so just thinking about the rationale behind why that's being recommended so doxycycline the great thing about that is that like you're covering your typical typical bacterial so,

In that episode I talked about earlier on, choosing antimicrobial, but used as an example of community-acquired pneumonia. So I go into a lot of depth there about which organisms are involved and what covers what, including doxychloroquine, amoxicillin, etc. And there's a slideshow attached to it, which does it in picture, because obviously it's a podcast. Sometimes a picture tells a thousand words. And this is a podcast, so we can't obviously beam a picture into your brains. We can. We can.

It's transmitting now. so yeah so you know that that makes sense to doxycline because it covers strep pneumo it covers hemophilus it covers mycoplasma and we see quite a lot of mycoplasma in sort of.

You know run every couple of years you get a big you know amount of mycoplasma so that's you know doxycline macrolides and then clindamycin is also protein synthesis we don't tend to use it for atypical infections but it has more of a use case in sort of skin soft tissue infections the theory goes that it inhibits protein synthesis so it produces toxin production by certain bacteria so often that's something that would be added in like a severe cellulitis sort of situation,

and obviously it's got very high risk of c diff and diarrhea so we don't use it all the time but that's sort of why that's there in that sort of bracket and there is some trial data to suggest that in necrotizing infection it does reduce mortality so interesting um so for no i'm just thinking aloud but i don't know if i should but i'm just thinking of my quite poorly controlled diabetics and if they had cellulitis but i wouldn't i would still go off guidelines and contact people and for

each of these antibiotics you know i'd go back to those microbe factors the host factors the drug factors so just you know clindamycin as an example of that you know micro factors there can be resistance so you probably want to check and make sure it's not resistant host factors so you know um it's okay in penicillin allergy there's not really much concern about renal function because it's not renal excreted. It's four times a day which isn't great. It's high risk of C. diff.

But it does get into tissue really well. So, you know, that's an example. Yeah, good job using that. Yeah. Protein synthesis. The other one is aminoglycosides, which you're not really using in the community apart from, I guess, like ear drops and eye drops. And then, so we've done cell wall, we've done protein synthesis. Next one is sort of DNA or folate. So trimethoprim and then solfamifoxazole with trimethoprim.

So co-tramoxazole or septum, however you want to call it. My favourite. The favourite. Yeah. We really like it in secondary care as well. So, you know, those both work on folate synthesis pathways, which is different in bacteria from humans. So very specific. So they've got a really wide range of activity, both gram-positive, negative bacteria. They've got some atypical cover. They also cover some parasites.

So, you know, we use them against things like some of the sort of more unusual parasitic infections we see in infectious diseases. They also have some antifungal cover so we use them against pneumocystis.

So yeah you know really broad you know they lost favor um but they've really come back in i guess with that you know you're mainly thinking about your um side effects you know the myel suppression longer use the hyperkalemia the acute kidney injury the risk of steven johnson syndrome those are the things i would probably coach people on yeah i was gonna say why is it falling out of yeah okay those are good reasons not to use them yeah they're you know they're great drugs if you're able to

monitor the patient and if you're using them for short courses you know less than seven days you probably don't need that much as long as a patient isn't someone who's on you know loop diuretics or known hyperkalemia and in the uncomplicated patient that's young and has there's nothing else going on a short course of cotrimoxazole should be safe but when you start to get these like frail elderly patients with renal dysfunction and that's where you can run into problems with cotrimoxazone so we

certainly from secondary care if we're discharging someone a longer course or there's those risks we would then arrange you know regular follow-up bloods and review and obviously we would coach the patient within that bracket the other thing i guess to think about is um quinolones so ciprofloxacin ofloxacin moxifloxacin, and they inhibit DNA gyres so they basically stop DNA production so they work in a different way um.

Again, they're broad spectrum, so they cover gram-negatives and positive bacteria, not all of them, but a lot of them. They cover atypical infections, they get inside the cell. But there's this MHRA warnings and the black label warning, which, like, you know, we can talk for an hour about this. There's so much discussion about this at the recent infection conference I was at.

And one of the issues is that the MHRA have issued a warning mainly because of the rare but serious risk of the kind of vascular aneurysms and dilatations or aortic root aneurysms or those sort of situations, which, you know, is a real, seems to be from the data, a real association.

But it's incredibly rare and we know that all drugs have side effects and many other antibiotics that don't have this warning in place have similarly severe and rare warnings which then raises the question of why is this warning in place and it's not in place for other antibiotics.

So you know i guess we now have guidance saying that we shouldn't use quinolones unless there's no other suitable treatments or you know in certain circumstances in scotland there's this group called the scottish antimicrobial prescribing group and they have they've issued a sort of quite supportive statement basically saying we recognize this warning but you know it's still okay to use this in certain circumstances i think it's tricky because at the

end of the day as medics you're making that decision for patient on risk management yeah and mhra are kind of trying to make that decision for you but if that's the best antibiotic for the patient then you might still need to use it i think it's just just makes it so much more frightening to use yeah exactly yeah like the risks sit with you the the prescriber which yeah and i think sometimes that is the right decision and we do use quinolone still so you

know and there's lots of situations there's a great antibiotic you know it works really well killing bacteria obviously there's other risks as well you know c-diff diarrhea you know tendinitis particularly in those on steroids yeah not just achilles tendinitis but you know the other one that's often missed quite often you see people of shoulder pain and it's your prospinatus tendon which is the second most common one.

I have seen that once yes yeah it's quite it's quite interesting like what shoulder pain you know the patient doesn't think it's anything to do with their antibiotics yeah oh and in some other antibiotic classes so you know I guess you've got your sort of metronidazole which is anaerobic activity which I won't go into detail on as nitrofurantoin for urinary tract and things like phosphomycin for for urinary tract. I think those are the main antibiotics that you'd be using in general practice.

We talk about classes and which antibiotic you use when for what.

One thing that's really helpful is the World Health Organization Access Watchware classifications. I don't know if you come across that. No. No. So this is basically an initiative by a silent pandemic antimicrobial resistance. There's been a lot of discussion about how do we make the best use of the antibiotics that we have?

How do we support prescribers to prescribe in a way that will not encourage antipocomial resistance and so they came up with this classification system it's called the AWARE classification so it's like it basically stands for access watch reserve yes i have a and e are small yeah yeah uk hsa have made a uk adapted approach for this uh international approach and they basically take all the antibiotics and say this is an access antibiotic so

the ones that you should be using first line watch which is you can use but they're not you know the second line and then reserve which is really reserved for use in you know mostly by infection specialists or the advice of them so that's a good way to think like should i use for example doxycycline or should i use clarifromycin you know it can it can help with your decision making if you're like well both are fine so um you can

then say well doxycycline and access antibiotic and clarifromycin is a watch one that's nice yeah another just addition to your decision making tools um just before we finish i didn't think that we could talk about an antibiotic episode without talking about resistance because i have a huge fear about it from a personal point of view because i just think we're going to get to this point where we can't treat infection anymore and it's going to used to be the thing that killed

everybody so i just yeah i'd like to know what's happening with that and if we've got any light. I guess if you think back to where antibiotics come from, they're mostly harvested or refined from, microbes of some sort of fungi or bacteria in the environment so as long as there has been.

Microorganisms producing antimicrobial agents there has been resistance so you know this is nothing new if you look back there was a paper and they looked at like an ice sample from like 30 000 years ago and they were able to find antimicrobial resistance this is not new and this has always been going on and the more we expose bacteria in the environment in humans but also in agriculture and in lots of other things, you know,

manufacturing to antimicrobials who put a selection pressure on for them to develop resistance. And you can see this throughout history. You know, you get penicillin, you get penicillinase in Staph aureus. Suddenly all your Staph aureus is resistant to penicillin. And as we go through and we get new, better in quotation marks, antibiotics that bypass resistance, very quickly the bacteria come up with a new one.

So our newest and best antibiotics that cover the carbapenem-resistant bacteria, which are the ones that we worry about, there is resistance to them already. Almost as soon as they're published, someone finds a resistant isolate. It really kind of drives it back to the answer to the antimicrobial resistance isn't new antibiotics.

It's using the ones that we've got appropriately, you know, only using them when there's infection, using the shortest dose possible and targeting the bacteria, avoiding long courses of antibiotics. That sort of stewardship angle there's so much talk about in the stewardship point of view there's too much but i think probably a really simple way of looking at it is looking up the access watch aware classifications, We'll link to those. They look good. They look really good. Yeah, they do. Yeah.

Yeah, so I think we'll wrap up for this episode because I know we've taken loads of your time. No, no. And I'm like swallowing questions. You know, you could do a whole podcast on antibiotics, which I have done. Yeah. It's a reason you... Yeah, and I'm sure I've missed out really important key bits about all of those antibiotics. So, sorry.

Jame and I have been trying to like go for each one. And so, you know, we've got the Idiot's Guide to X. So there's an Idiot's Guide to Penicillins, Carbopendins. So probably too much detail. But if you want more, then it's there. It's great. If you want the deep dive, they're there. Definitely.

It's sort of if you were to try and summarize our wonderful conversation, any kind of key learning points that you want GPs and people working in primary care to kind of take away from them for the chat today?

Yeah, I think choosing antibiotics can be either simple, complicated, or complex for your patient and when it's simple you know it's simple isn't it you just follow your local guidelines and and that's all good and well and you don't need to think about it more when you're getting into complicated you know you might be looking to things like your NICE guidelines or going outside where things are and there should still be an answer that you know applies to that

patient where you're getting to the complex realm where you know it's not clear I guess involve a friendly local microbiologist or infectious diseases specialist, or ask the other GPs in your practice. If you're thinking about antibiotics, you know, there's a couple of ways you can think about it. You can think about the sort of microbe factors, particularly as they're actually infection, the host factors and the drug factors.

And you can also think about the spectrum of activity, you know, your gram-positive cocci, bacilli, gram-negative cocci and bacilli, which ones cause the infection you're treating, does this antibiotic cover them or not? And then finally, we should always be thinking about antimicrobial resistance when we're prescribing antibiotics. And the most useful thing for thinking about that is the UKHSA adaptation of the WHO Access Watch Reserve classification, the AWARE classification.

So if you Google that, it will come up. It's really useful and be thinking about, you know, which one should I use when. Perfect. That was a wonderful summary of our chat, actually. You brought that together very well at the end. Thank you. Just listen to the summary for the... At the beginning, that's all you need to listen to.

So Sarah I really really enjoy these episodes with Callum I think it was lovely to be able to speak to him I really enjoy his and James podcast and it was just a joy to be able to do it and I'm also a little bit biased about these episodes because Callum's based in Edinburgh I was able to actually do it in person which was so lovely again and to be able to to record with them in the room and so I really really enjoyed these ones we're a week down the

line do you want to share what you took away from this episode yeah um yeah no I think it was it was a really lovely memory of the recording um and it was great to meet them um it was just lovely i think that collegiate feeling um uh one of our friends recently said he was a surgeon who listened to our episodes like oh you guys all talk to each other so nicely and actual learning points from the episode i really like just yeah just going back to the basics antibiotics thinking

about the the structure so thinking about the microbe the host and the drug factors um also thinking about all right the thing that i think i've been using but i'm now going to actually properly structure it as the brand and benefits risks alternatives and nothing um really really good way of guiding patient conversations um and yeah just it was full of of really good structure and resources wasn't it yes it was.

And actually just as an aside I mentioned in the episode that that's used to tell patients, in kind of obstetrics midwifery and I couldn't remember what the acronym was but they add an I in so it's BRIAN and the I is what does your intuition tell you what's your kind of gut feeling about it so as a patient.

Kind of fits a bit more i guess um for thinking about oh so is it um the patient intuition or the clinician and the patients this is as a patient uh to think about to remember to ask what's the benefits the risks the alternatives what's your gut feeling and.

What happens if you do nothing right um oh that's great but yes i agree i thought that um it was really nice to go back to that and uh to think about kind of why you're prescribing antibiotics and yes he said that normally it's very straightforward you've got guidelines you can follow guidelines but if it varies off that at all it's really nice to have a framework to actually go okay well if I'm thinking about all of these different factors

I should be able to pick at least the best antibiotic for the for this infection in this patient and that helps you kind of feel a bit better about the fact that there's no maybe set guidelines and actually going off of that his framework that he introduced us to that was the simple complicated complex and chaos um was just lovely um to be able to categorize things like that as well yeah i've used that since and i've really enjoyed it i think it's just nice to have

a structure in your head of once you can pigeonhole things a little bit better it just the sort of a burden of uh clinical reasoning seems to seems to have less yes yeah it's it's really interesting because you're kind of stuck in a problem and you're like oh where's this sitting it's like oh okay it's here I mean you could kind of forgive yourself a little bit I like that that's good um I just see what else I've written down I've written down broader isn't better oh yeah.

I like the access watch reserve that he was when he was talking about antimicrobial resistance. Yes, absolutely. And just making the best and the fact that the answer to antibiotic resistance is to make the best use of the antibiotics that we have and use them the most appropriately. It was just nice to reiterate as well, I guess. But yeah, we went through so much in this episode. I think the episode probably is enough for everybody listening, really.

But it was just nice to hit you up with what we took away and remembered the most, I think.

But hopefully you enjoyed it and we do have another episode coming that is a little bit different it's talking more about the actual procedures and things and the black hole that is microbiology so that was really eye-opening and we really liked that Yeah, absolutely, So yeah, thanks for listening Till next time On Primary Care Knowledge Boost. Music.

This podcast has been able to continue to date due to the support of GP Excellence, Wigan Borough CCG, Greater Manchester Training Hub and the GP Fellowship Programme, as well as Greater Manchester Health and Social Care Partnership. Just a friendly reminder that these podcasts are for healthcare professional education and shouldn't be used for medical advice by the general public. This episode was recorded in Greater Manchester in 2025.

Guidelines can vary by location as well as over time, so always check for up-to-date local and national guidelines before making treatment decisions. The content is based on our interviewees, opinion and interpretation of current best practice. It's your responsibility to use your clinical judgment before applying or relying on information solely from this podcast.