Nov. 18, 2025

150: What Every Vet Should Know About Antimicrobial Resistance. With Dr Kate Worthing

150: What Every Vet Should Know About Antimicrobial Resistance. With Dr Kate Worthing
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Season 1

Stop scrolling -  I know what you’re thinking: “I don’t want to listen to someone preaching to me about antimicrobial resistance  - it’s boring, and it just makes me feel guilty!”

 

Here's a promise: you'll find nothing boring or preachy here. What you will get is interesting science, practical tips, and zero guilt trips. 

Dr Kate Worthing is a senior lecturer in veterinary microbiology, practising clinician and passionate antibiotic resistance researcher, and she’s about to change how you prescribe.

Together we unpack why the way you use antibiotics in general practice is more than a clinical choice - it’s a responsibility that affects your patients, your team, and your future cases. From unseen pathways of resistance to pragmatic stewardship strategies you can implement this week, this is essential listening for all veterinarians. 

You’ll learn:

  • Why antimicrobial resistance is not just a global issue - it’s personal, and it’s already in your consult room.
  • How selection pressure works beyond the infection: across the microbiome, the patient, and the environment.
  • Why MRSA isn't really the problem you should be worried about (and where you SHOULD point your attention).
  • Where resistance risk is highest in small animal practice.
  • What “good prescribing” looks like in real life
  • How to find and apply trustworthy prescribing guidelines without slowing down your workflow.

 

Resources:

AMRVC

https://www.amrvetcollective.com/

https://www.amrvetcollective.com/home/guidelines/

WSAVA Infographics

https://wsava.org/committees/therapeutics-guidelines-group/

ISCAID

https://www.iscaid.org/guidelines

Understanding the mechanisms of resistance

Video

 

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Understanding Antimicrobial Resistance in Companion Animal Practice

Antimicrobial Resistance (AMR) is a critical issue in companion animal practice that involves complex mechanisms and has far-reaching consequences for the patient, other animals, and humans. It is often compared to climate change because the consequences of current actions, such as inappropriate antibiotic use, may not be seen immediately but are accumulating.

Wider Repercussions and Global Prevalence

The repercussions of inappropriate use extend far beyond the patient in front of the vet. A resistant bug created in a patient can enter the environment (e.g., urine in a park near a bubbler) and spread to other animals or humans, especially if the resistance genes are carried on plasmids that can move into waterways or the food supply.
While resistance rates vary greatly by region and type of practice (dermatology clinics see more resistance), rates in the US and UK are often slightly higher than in Australia, where rates are estimated to be around 10–20% for common resistant infections like MRSP and ESBL E. coli.

Challenges to Antimicrobial Stewardship (AMS)

Being a good steward is difficult in everyday practice due to several constraints:
  1. Time Pressure: Vets often work under tight schedules (e.g., 15-minute consults) which makes it challenging to take a thorough history, perform necessary diagnostics (cytology, swab), diagnose the underlying cause, and educate the owner, leading to missed opportunities for better decisions.
  2. Clinical Pressure: Vets want the patient to improve rapidly and avoid client dissatisfaction (e.g., the client returning because a lower-tier drug didn't work). This pressure can lead to the easy decision to use "the big guns" and be more aggressive with antibiotic choice.

Practical Steps for Good Stewardship

To combat these pressures, a three-step framework (pre-treatment, during treatment, and post-treatment) can be used.
1. Pre-Treatment:
  • Diagnosis: Ensure you have a diagnosis requiring treatment.
  • Need for Antibiotics: Determine if antibiotics are actually necessary. For instance, most superficial skin infections may resolve with shampoo alone and do not need oral antibiotics. Similarly, antibiotics are often unnecessary for male cats with lower urinary tract disease, diarrhea, or cat abscesses.
2. During Treatment (Drug Choice and Duration):
  • Use Guidelines: Consult available guidelines for skin disease, respiratory disease, and urinary tract disease.
  • Lowest Tier Drug: Choose the drug that is effective for the site and of low importance.
    • Fluoroquinolones (like enrofloxacin) should be avoided unless clearly indicated and are restricted in some regions (e.g., Germany requires a culture before prescribing them). They select for resistance at a higher rate because they are broad-spectrum and work by inhibiting DNA synthesis in all bacteria.
  • Shortest Duration: Treatment should be given until the infection is healed, rather than treating beyond clinical resolution or always insisting the owner "finishes the course." The goal is to minimise the exposure of the microbiome to the drug.
3. Post-Treatment (Follow-up):
  • Responsibility: Avoid placing tough cases in the "too hard basket". Taking personal responsibility for follow-up ensures continuity and prevents the patient from "pinballing" between different vets and different antibiotics.
  • Follow-up Plan: Establish a follow-up appointment, potentially offering a reduced-cost follow-up to encourage the owner to return.
  • UTI Management: If a patient is clinically fine after a course of antibiotics for an uncomplicated UTI, do not culture the urine at follow-up, as finding non-clinical bacteria can lead to confusion and unnecessary additional treatment.
Client Communication:
When discussing stewardship, vets should frame their choices in terms of the animal's long-term health, explaining that they are saving antibiotics for when the pet is truly sick and needs them, thereby preventing a resistant infection that could be fatal. Owners are also generally amenable to decisions when the negative effect on the animal’s microbiome ("biome") and potential cost savings are explained.

 



Back in 2022 I recorded an episode called Antibiotic Myth Busting with Doctor Rihati Scarborough.Episode 60 to be exact.That conversation completely changed the way I use antibiotics in everyday practice.If you haven't listened to it yet, someone on a vet chat group called it Obligatory Listening for All Vets.
Well, I think we've just created another must listen episode on antibiotic use, Inventory Science, because when Doctor Reid opened our eyes to where we can be much better antibiotic stewards, Doctor Kate, our guest for this episode, goes deep into exactly why.And I think you need to know this.
I'm Hubert Hemstra, and you're listening to the vet film where if I were to start selling merch, our first T-shirt would say put down the metronidazole.No, seriously, I think I'd wear that.I think I should start a merch store.Our guest for today is Doctor Kate Worthing, a senior lecturer in veterinary microbiology, but also still a practicing clinician and a passionate advocate for antimicrobial stewardship with a PhD in methicillin resistant staph pseudo intermediates, which you'll soon get to know a whole lot better.
Kate doesn't just teach the stuff, she lives it.As you'll hear, her personal journey with resistance goes way beyond just theory.In this conversation, we get real about why being a good steward is so hard in the chaos of everyday practice, but why we really shouldn't stop trying.
We learned about the hidden pathways of resistance, how our prescribing habits affect not just the patient in front of us, but animals and people far beyond, and what practical steps we can take before, during, and after treatment to do better.We'll also learn where the biggest resistance risks are hiding and which guidelines are actually worth your time.
Look out for links in the show description to those said guidelines, which are guides that will help you make better antibiotic decisions in everyday practice.Including a link to a little animated video that further clarifies the mechanisms of resistance.Which I know sounds a bit nerdy, but let's face it, if you listen to the Vet Vault, then you're a nerd.
Just the best guy.OK, let's shake up our antibiotic habits with Doctor Kate Worthing.
Thank you so, so much for joining us to talk about something that I think has become a bit of a soapbox of mine.Hello Hugh, thanks so much for having me.I'm like a long time listener, first time caller.Okay, cool.So antimicrobial resistance and resistant bugs.This is your thing.
You're a practicing veterinarian, still a teacher as well, which I'll say you've got many different perspectives on the same topic.So I'm really curious to hear how we make this practical.As I just said, it's a bit of a soapbox of why you'll be very proud of me.I just did a talk a couple of weeks ago in Singapore, a, a lecture about 5 things I've learned from making the Redfield podcast that have changed the way I practice.
And #1 on my list was how I think about prescribing antibiotics.So I do like to talk about it.I do like to think about it.I do actively try to be better at at at antibiotic stewardship in my day-to-day practice.There's moments when I go to the shelf and reach for an antibiotic, I try to take a pause and go, do I need it?
Do I need that one?But having said all of that, and I feel like it can be a bit preachy, but I do sometimes feel like it's, is it necessary to be so paranoid?Because I don't feel that in my day-to-day practice, I actually see that many resistance problems other than ears or is ceremonious in the year that's.
But beyond that, is it a now problem?It can feel a bit like climate change when you hear about this and it's this big scary thing.But for today, I'm still going to drive my Ute and fly everywhere and because I don't feel the impact of it in my day-to-day life yet.Am I?Am I wrong?But as.You are right in like saying that it's like climate change for sure because our actions, OK.
So say if we had like a, a coughing dog and it had pneumonia and if we gave it pred and we suppressed its immune system, then it's going to get worse within two days.And that's why we don't give it pred because we're going to see the immediate fix soon and it's going to be dramatic in that patient.
I totally agree that the consequences of maybe using an antibiotic when you shouldn't, you may not even be the vet that sees it or this patient may not be the patient that has issues with it, but it's coming for you and it's coming for us.
And I will say that for me personally, you know, one of the reasons I went on this personal journey is because my father died of an antibiotic resistant infection.So I've got a personal connection.But for me personally as a vet, it, it kind of didn't come home until I was doing a clinical record review and we were tracking a case of a dog that had an exceedingly resistant skin infection.
And it had 1000 page record.And we were looking at all the times when the vets could have made better decisions about using an antibiotic to kind of get this narrative of like, look, these are the opportunities when you could have done better.And I looked back at the record.And then there in 2016, little old me, little old me, I was one of the vets, even though I am one of the lecturers that teaches about stewardship, and I was one of the vets that contributed to this resistant infection that happened years later.
So I guess it wasn't until I had direct evidence that my actions had contributed to it that I really, on a personal level, started thinking twice.And I guess I use that story for myself.But now I want to tell all the vets, like I've now seen that my actions did lead to contribute to selecting for resistance.
And everyone else's actions are likely to do that.Whether you see it or not, it is happening.So how I'm curious how what happened?What did you do?With that so.That led to what that helped lead to.Resistive infection, just we, we basically understand the broad concept of selection pressure.
Does that selection pressure rings true to you here like what's happening with selection pressure?So we, we kind of understand that if we use an antibiotic, an animal has a microbiome and maybe one in a million bacteria are resistant in their microbiome at that time.
But when we use the antibiotic, all the other 999,000 bacteria are killed.And that one little guy who's kind of a weakling, he's like when he grows and he's selected for and now he is populated the microbiome.Next time when the animal gets an infection or if they get an infection, now they have a resistant bacteria and that's the one that's going to cause the infection.
Therefore our use, first time antibiotic selected for resistance the next time.So what happened with this one patient?It was a case.It's what we all see in general practice and it's kind of the case that we always hate because of skin disease.This was before we had Apoquel and Ciderpoint.
Things are a little bit different now we have those.So this dog has pyoderma, as we're always taught in uni, and we know in our heart that sometimes we can't be willing to think about it.If a dog has pyoderma, then it has underlying skin disease.So it really got to take the time to address that.And so I was tracking this patient's records to see when did the vets do cytology before they prescribed antibiotics.
And we can get to the kind of principles about stewardship in a point that in a SEC, that's one of the things that vets should do.Ask yourself, does the patient have an infection?Where is the infection?Do I even need to give antibiotics?And so if you're talking about skin, one of the first things you should do is does it have an infection?
Well, I should look on the microscope because it could be malasisia, which won't get better with antibiotics because it's a yeast infection, or it could be staph.So we're looking through each time this patient came in 1000 long history.How many times did vet do cytology?Maybe 1/3 of times that the specialist vets would do cytology.
But in general practice, maybe 1/3 of times.So I was looking at this one instance, the dog came in, the vet says, OK, yes, she's got skin nodules the the pred and the cephalexin we're working.But when she came off the cephalexin, they stopped working.So we'd have to do something.
We think that we have to address the ACP, talk to the owner about ACP.There's some cephalexin.There you go.So that vet kind of missed some principles.They said I think that you have an infection, they address the underlying disease, but they didn't confirm an infection by doing cytology and they didn't do a culture to see if it was resistant.
They just gave the antibiotics and that that was me, even though I am the the vet that talks about this now anti microbial stewardship.So that kind of brought it home to me.Was that in the days before you were talking stewardship or?I was already, probably already just not.
Yeah, I was busy.I was busy.It really brought home to me what vets, what we actually experience on a day-to-day basis as vets.You know, I was so paranoid by this, I went back to the appointment book on the day when I saw this client and it was a Sunday and I had back-to-back 15 minute consults.
This was the 14th out of 16 consults in that morning.The next consult was a coughing dog consult before it was a muscle tumor.So am I or vets in general, Are we expected to be able to take a history, look at the antibiotics that we've had, diagnose the underlying cause, do cytology, talk about finances, take a swab, all in 15 minutes.
And I guess this is this is just like a come to Jesus moment to me of why stewardship is hard.If me who's talking about stewardship realizes that it's hard and I don't have this, I have the constraints that I couldn't even do it in that console.I understand why it's hard, but I'm still saying we should do it.
And I'll add to that another factor that complicates it and it's this personal experience as well.The other reason why we sometimes not as good as we want to be is you don't want to mess up the case in front of you.So I want this, that patient to get better.
I want this client to be happy and not come back next week and say, hey, my dog's not any better.I spent money on a consultant.You didn't give me antibiotics and now it's worse.Or maybe I chose a lower tier antibiotic because I want to be a good steward.
And then it didn't respond and it actually needed a, you know, I chose amoxicillin instead of amoxy clav and it didn't do the job.So it's easier to just go, I'll just go the big guidance, be more aggressive and cover my eyes.You're exactly right.I think like you said, when you're in the pharmacy, we do need to when we're like literally reaching for the drug being like, do I though?
Do I need this one?Because clients whenever I've had the conversations, when I have time, I will say to say, you know, I'm not going to use this antibiotic.I'm going to use that antibiotic or I'm not even going to use an antibiotic.I'm going to use a shampoo because I want to save the antibiotics for when your dog is really sick and she really needs the infection that the antibiotics.
So if I use an antibiotic in her now, I don't want her to have a resistant infection later that we can't treat and she'll die from it.When I speak to owners like that, they are so amenable with your choices.Even if they find that the choice you made initially, you did need to go back and make a different choice, there they are.
I really find 99 times out of 100 an owner is going to respond if we frame it that way.I agree.I agree actually.I haven't used that line about the resistance so much.I feel like owners are generally not completely oblivious to the concept.
They hear about it in human life as well.Luckily it's the one benefit of the whole anti pharma movement as well.The anti big pharma people like Oh yeah, I don't want chemicals.So if you go well, it's one less thing I have to give your animal and then I also go on the Biome thing.I will say to people, five years ago, I would have given an antibiotic in your pet.
Now I've learned a lot about how antibiotics work and the potential negative effects they can have in your pet because of its Biome.And people also know the concept of Biome people.Yeah, it's, it's out there.So I'm going to try and not an antibiotic.I think it's going to be better.But if I'm wrong, if it's the wrong choice, then you're going to see ABC and D and then you come in and then we start an antibiotic, no questions asked.
Are you OK with that?And I've, I've not yet had anybody say, no, just give me the antibiotic, please.And I and I add in costs.I say also I'm going to save you 60 bucks by not sitting home like an unnecessary.Exactly and.They go, Oh yeah, shit, I'm on board.Yeah, because I really feel that every owner's motivation first is going to be their animals motivation first.
But sometimes animals health is their motivation first and then, you know, at varying degrees cost is right under that.So if we speak to both of them, the animals health and why we're doing it in relation to the health.And then secondly, the cost, unless we're talking about a life threatening infection where we rarely are unless you're an emergency, they're very amenable to when we have the time in our consult to explain those things to them.
I want to get into what we should do, but before that, just going back to what you described of how that happens.One of the possibly the first interview I did with Doctor Reece Karborough about antibiotic existence flicked a couple of switches in my head and I just want to make sure I understand it correctly.
So I always understood, and this is the talk I did in Singapore, I understood what you described there.That's how resistance happened.I pictured it's me versus a population of pathogens that's making my patients sick and I'm there to destroy that population of pathogens.But possibly there may be a resistant one in that population.
So I'm going to kill all the baddies minus the one resistant one, and then that one can multiply.And now I have a resistant population of pathogens.But what she explained, what's sort of the light bulb moment for me was that I might actually completely eliminate the pathogen that I'm trying to eliminate effectively.
But because I'm also killing bugs across the entire microbiome, so commensals, healthy bugs, gut bugs, I'm destroying them as well.But some of them may be resistant and it might be a complete innocent bystander that actually survives and multiplies with a resistant gene.
And then that guy can go and give the resistant gene to a pathogen.Is that correct?Did I understand that correctly?Yes, you understood entirely correctly and that's what we think is happening, especially with like, have you seen those little old cats that just have nightmare resistant infections?
Maybe you haven't, but when you do you'll be scarred for life.We suspect that's what's happening, especially with the really bad multi drug resistant UTI's that old cats get because cats don't get UTI's unless they're very compromised anyway.It's very hard to find hard and Feist evidence, but I, I think Ree and the team in Melbourne agree that there's a chance that the use of broad spectrum antimicrobials, long anti antimicrobials.
So cefibesin, which is convenient, which again, I've used on a weekend when it's busy and there's a cat with Cellulitis, they will kill the pathogen that we're wanting to treat, but they won't kill the little old Proteus or the Pseudomonas that was there.
And Proteus, which is like if Pseudomonas and E coli had a baby, that's Proteus.So it's like kind of a good pathogen.It's got lots of resistance, like Pseudomonas, Proteus will survive.It's got its resistance genes on a plasmid.And either it will keep it for themselves and it'll just wait until the cat's like 18 years old and got kidney disease.
And it's like, now's my time to shine.Or it will give that plasma to E coli, who is a good pathogen anyway.So you're right, it's not the ones that we were trying to treat initially that have kind of grown muscles and become strong.It's usually the little bystanders.And they're just going to cause problems later in life when the animal is more compromised.
OK, the other concept that I also didn't grasp or think about before I started thinking about this more.What because your, your case that you described, that was the resistance problem manifested itself in the patient that you treated.But sometimes that's not the case.
It's not always going to be that particular patient because I now create this resistant bug in this patient.This patient might be fine.So I don't see those direct repercussions.But this patient goes to the park and another dog sniffs its butt or he goes home and licks the child or something.And that bug is now in the environment and it's a resistant bug and it lands in the wrong person who gets an infection or a pneumonia or a skin wound and animal or human.
That's the other part that I went oh, oh, there are much wider repercussions to my antibiotic cowboy attitude than just this patient in front of me.Yeah, absolutely.Especially for so the kind of two most common ways that they'll get resistance bacteria is that they have a gene that they need and it gets mutated and then they the antibiotic doesn't work anymore.
That usually will just stay within the species.And that's how methicillin resistance works.If we want to get really nerdy and talk about that in sick, that's usually not as much of A concern in spreading to between humans and animals because it's just that gene in that species.The plasma thing is the big concern.
That gene can go into the waterways.The waterways can go into the food supply and go to people that way.Or like you said, maybe a little old dog who's a poodle.You know, like those blind poodles in wheelchairs who their back legs don't work and they've got to resist an infection.As they're going through the park, they pee out their resistant E coli infection and it happens to be near a bubbler and the water gets contaminated and the kid gets it that way.
Even if it's not a coli, maybe it's somebody else that just picked up the plasmid.So yeah, it's not just the single animal that's at risk.It's not just the animal in your hospital that it's at risk.It is humans that are risk as well.We just don't know the extent that they're at risk, but we know that it's a possibility.
So let's talk about extent.I said at the beginning, it feels like a distant problem.How much of a problem is it now?Like how much resistance are we seeing in veterinary science specifically?Well, start with a couple of caveats about what we know.It depends on where you work because the rates of resistance are governed by the type of drugs that are used and how often they used.
So the resistance in Australia is going to be different to say Southeast Asia or Japan or the States.So I'll talk about what we know in Australia.Secondly, the type of patients you see, if you're in a dermatology clinic, then you're going to see more resistance because these dogs are likely to have a lot of risk factors for resistance.
If you're in AGP clinic, you will see less resistance because you're seeing more animals that haven't been in hospital had antibiotics.And the last caveat is we've done some big national surveys that I've been involved in.The caveat for those and the statistics, I'll tell you is that they're just based on the animals that have had culture and susceptibility done because it's very difficult for us to go out and just survey the baseline.
So it's likely to kind of inflate how much resistance we see because it's only when vets have been like, oh, I better send a culture.But in any case, we think that the two we know the two biggest pathogens that are causing resistant infections in Australia are in dogs and cats, E coli and staff.
And this is a slight bugbear of mine and I don't care if people remember it or not, I do for students.The staff we're talking about is not staph aureus, it's not golden staff, it's not MRSA, it's staff student to Medius, which is the doggy version.
The main reason I think it's important for us as vets to have knowledge of a difference is that MRSA is an important zoonotic pathogen, but it's rare.It is rare.I'm not talking about MRSA, I'm talking about MRSP, which is methicillin resistant staff suit intermediates.
It's common, but it's not zoonotic.Very rarely zoonotic.It's kind of a slight importance for us with our messaging because if we intersect with the human world and we as vets are saying that we have a problem with MRSA, they kind of start to blame us for a thing that's not actually a problem.
MRSA is not a big deal in companion animal health.It's staff suit intermediate, so it's not much of A stenosis.Does that make sense?It does.I did, I had no idea.So Staph aureus, what does it do in dogs?Like do we even because I'm I'm obviously see the intermedius, that's the skin one, right?
That's what we all battle all the time in dermatology practice.So, Staph aureus, is that mostly a human bug that happens to be in bugs, or do we see it?So if you see it, it's actually a reverse sewanosis.You can think of it as an iatrogenic infection.Most of the time if you see an MRSA infection, it is likely to come from you, your clinic or the owner.
If we're talking about stuff or is that's it's, it's useful for infection control in your clinic.If you're seeing MRSA, there may be a hand hygiene issue, there may be a staff that's a carrier.MRSP is the dog skin pathogen and it's far more common.
So we did a survey.This is, you know, you really wanted to know how come is it?So about 10% of the infections in Australia that was 10 years ago were methicillin resistant staphs into me.It's about 10% of the skin infections.But remember, these are just the skin infections that are getting cultured, whereas .3% were MRSA.
So it's, it's not common.It's important when it happens because you don't want to spread it to the owner and things.But you said before here that you haven't seen it often.That's because it's not common.If you do see it, MRSA, yes you should look at your infection control and you it can be zoonotic between the patient and the pet, but it's likely that it came from a human.
Why?Why is it M methicillin resistant?Why does methicillin even I don't I've never prescribed it.I don't why do I care if an animal's resistant?To me, I hate the naming of it.It's so annoying.It's, it's unhelpful.OK, I'll see if I can describe the timeline and maybe that will help.
Why we call it methicillin.So in the 40s they discovered penicillin and they started using it widely in the World War.We it turned the case of the wall because we were treating infections and patients were living surviving when they wouldn't have before.So penicillin was used, Penicillin, penicillin, penicillin and widely from 1945 to 1950, next minute 1951 resistance started occurring in penicillin.
And that's because it got an enzyme that could break penicillin down, penicillin AIDS.So they were like, oh, OK, well we better make a new drug that even if they're resistant to penicillin, we can still treat it.So they made methicillin, which had this like extra strong beta lactam ring that couldn't be broken down by the enzyme.
So it's methicillin.Within a few years of methicillin being introduced, they saw resistant to it as well in Staph aureus.So then that name stuck methicillin resistant Staph aureus.And it was resistant not just because of an enzyme.How penicillins and beta lactams work.
They target the little protein that builds the cell wall and it's called penicillin binding protein.How methicillin resistance comes about.It's not just this enzyme because it's got the strong ring.It has a different shaped penicillin binding protein.So penicillin won't work, oxycillin won't work, methicillin, anything that binds to that penicillin binding protein, which includes cephalexin, cephavesin which is convenia, amoxicillin clavulinate, any of the broad families.
So what was easy to treat with?You're like, oh, I'll use amoxicillin or I'll use amoxicillin clavulinate or use cephalexin.All of those drugs rely on binding to the penicillin binding protein.So when that penicillin binding protein is changed, they don't work anymore.
So the name has stuck methicillin resistance, even though in the lab they use another drug now to test it, oxycillin.In veterinary medicine, we don't use any of those drugs, but it's just, I guess a code for us is vets to know that any beta lactam won't work.
OK.That makes a lot of sense.Thank you for explaining that.So it means that it might be sensitive to other groups of antibiotics, but we've just knocked out an entire and very large and very relevant group of antibiotics.Yeah.So that the unfortunate thing is that when they get that methicillin, it's an altered gene.
They get it through.You can kind of think of it like a plasmid, but it's specific to stat.They call it a cassette chromosome.So you know the old school cassettes put it in your tape layer and off it goes.And the cassette that carries that altered binding protein, it's like a mix tape of resistant genes.
So they'll get that binding protein, but they'll also get tetracycline resistance and they'll also get sulfonamide resistance and aminoglycoside gentamycin resistance.So normally when they get this make a gene, that's the gene that makes this mutation, they don't just get one resistance gene, they get a lot.
So MRSPMRSA, they go from no resistance, too high levels of resistance to lots of different drugs because they've got this special chromosome that's coming.Mixtape.I think it's for our younger listeners.They probably have no idea of the joy of the mixtape.
OK, I mean, I know then I was going to say like, oh, ACD no, that's still old school.Like a Spotify mix.Playlist.A Spotify playlist.Playlist it's.A.Yeah.So even if that's all kind of too boring and nerdy to remember, I guess it's just to say they they've got a playlist, they go from nothing and they get their MRSPP playlist.
And that will give them resistance not to just one drug class, but usually 3 or 4 drug classes.So you're really limited in the drug you can use once you get an MRSP.OK, right.So that's the Staffs you mentioned.E coli is the other one.It's about the same about 10% to 20% of UTI's when we culture them.
So remember we, we know from the work that RE and her team do that we're not very good at culturing in the 1st place if we don't need to.So it's we're probably lower rates overall.But anyway, when we culture them, 10 to 20% of them of E Coli's resistant and E coli is causing 80 to 90% of the infections.
It's, it's one of the most common infectors of UTI.So E coli, the one we're worried about with E coli, they're called ESPL.So that stands for extended spectrum beta lactamase.Essentially they're the ones that are resistant to amoxiclab, which we all know that Amoxiclab, that's what we're going to be reaching for.
Before the guidelines came out to treat E coli, they're the ones we're worried about.And about 10% of UTI's are due to ESPLSI.Guess the concern about ESPL is compared to the Staffs is that staph is quite species specific.
Staph aureus likes humans.Staph student to medius likes dogs.E coli has strains that are very happily going to infect humans, cats and dogs.So they will very happily, in a little zoonotic triad, transmit between those three species, humans, cats and dogs, if that person or that animal has the right underlying disease to allow infection.
So am I right in saying from what you discussed the inventory signs are primary consent areas clinically for resistance it's going to be skin and urine.Are those the the big issues, whereas you always hear about the gut Biome and all the gut bugs and don't use antibiotics for diarrhea and all sorts of those things.
Do we worry about other or pneumonias, all those sort of things?Do we do we have issues in in other clinical areas or is it mainly focused on those two?Well, see, that's a great question because we asked for where the pneumonias coming from.They're coming from gut flora if it's aspiration pneumonia.
So if you selected for resistant E coli or if that dog was carrying a resistant E coli, that's going to end up as a resistant E coli aspiration pneumonia.If they have a UTI, it's often going to come from their own microbiome, whether that's their genital system or their gut.
So yes, we're talking about these are the main infections we see.They're the most common skin and UTI.It's just that the other infections are a bit less common.Diarrhea is a whole nother kettle of fish.But if you think of it like, you know, everyone used to love to use metronidazole, we've realized we don't need to use it so much.
One of the things with using metronidazole is if we do use it, maybe we will kill off the friendly anaerobes because that's what it kills.We'll kill off those and they're not so friendly.Strains of E coli might overgrow, and then they're ready to cause a new UTI when that animal reaches the age of like 23, when it's a cat, or if it's a dog and it becomes incontinent.
So I'm talking about UTI and skin, but that's just because they're the infections that we see.But the reservoir for UTI is pneumonia.That's the gut.That makes sense.Thank you.All right, So are we at how to be better?Practical advice for how to not promote this as much, if at all?
I, I don't think we can prevent it because it's just a natural occurrence.These bugs that have the resistant genes, they are generally less fit.They're not as good at causing disease as ones that don't have the genes.So this is where the microbiome is so important.
As long as the animal has a varied microbiome, then even if they get an infection, if they have diversity in there, then it's going to be the ones that aren't resistant that will cause infection.So what can we do about it?Which is, yes, there's always a positive thing.What should we do about it?
First of all, one thing I've learned is that it's difficult for us to do things in 15 minute consults.So at a management level, we always need to be very strict about giving.That's the time to be good stewards.
So if we're ever dealing with an infection, a, a UTI wish we should be looking at you're in cytology or an E where should we should be looking at a swab or skin where we should be looking at cytology.We need those 30 minute consults.I know that a lot of clinics are already doing this, but having experienced myself and going down this massive guilt tunnel when I hadn't done the right thing, we have to remove those barriers for vets to be good stewards in the 1st place.
And one of those things is simple.That's just good scheduling.What else can we do about it?I, I've looked at a lot of good stewardship programs.There's a lot of good resources.Personally, what I think helps me be a good steward is think about what can I do pre treatment, What can I do treating the animal and what can I do post treatment.
So those are the three steps of stewardship that I find kind of help me on a practical level, say that say at a patient level, like if we're dealing with a Piogena skin infection pre treatment, how can I be a good steward?Pre treatment means make sure that you have a diagnosis in the 1st place, that you need to treat it, have a good diagnosis.
Secondly, decide does it even need antibiotics?Because most cases of skin infections, if they're superficial, most cases don't need antibiotics tablets at all.They'll get better with the shampoo.So that's an example of pretreatment being a good steward.
Decide not to use it at all.And then if you decide it does need it, say it's a deep infection and it's not going to get better, then make sure you're using the right duration.We're really shaking.That kind of dogma that was around was like treat beyond clinical resolution.
You got to treat for a long time, finish your course.No, that's out.Treat until it's healed.And that's all because we want to minimize the exposure of the mycobiome to that drug.So use guidelines where they're available.There's really great guidelines for most animals and most body sites now.
So we've got them for skin, respiratory disease, urinary tract.So they're really great resources.There's some really great posters that you can look at, but essentially they're about use the drug that's going to be effective for that site.Use the drug that's of low importance.This means don't use androfloxacin unless you have a very clear indication.
Don't use those important drugs.And then after treatment is something that we forget about.But again, when I was reviewing that thousand page record, OK, maybe I'm the only vet that does this, maybe I am.When you get those too hard basket cases and you're like, oh God, this is too hard to deal with.
Like just see another vet next week because it's it's too hard.I know it's refractory.I know it's resistant.Like please come on a day when I'm not here.That ends up not being a service to the patient and ultimately society.Because if another vet sees it, maybe they're not going to have time to read your record, so they're going to give it a different antimicrobial.
If we take personal responsibility for the patient, then we are the ones that know well this is what causes it's had.This is what's worked, this is what has not worked.I hope I'm not the only one that does the 2 hard basket thing, but I think if we each take a little bit more responsibility and just stick with these tough cases then they're likely to not become such a nightmare as I can see they have in the past when I've looked at these resistant infections.
So what do you do afterwards?Because I'm getting better or at least more more mindful of that before and during.To me, the talk I gave at Singapore, for me it goes, do I need it?And in a lot of instances I don't, as you say, skin, but also, you know, don't use it in diarrhea, don't use it in a male cat with a urinary tractor.
I'd use it in a cat Abscess.There's a longer list of things where it used to be always antibiotics, which now is probably not necessary.So I try to be educated and mindful about that.And then as you say, lowest tear antibiotic which needs a resource, which I'll come back to and then shortest possible duration that's they're going to fix the problem.
But then after what you do after, is there anything you can do to damage control?Damage control, well, even just having that follow up and again, this might come to practice management if there's scope to have a reduced cost follow up so that the owner is more likely to come.
Because you know, a lot of the times, and I do this many times as well, is like, take this, it gets better, see you later.Never again until it happens again.We really should be following them up regardless because then we start to grow our own knowledge.These cases, this did worked.
This didn't work because when they don't come back, yeah, 9 times out of 10, it's probably because they got better.But it also could because they didn't get better and they're like, oh, this fit gave me that antibiotic didn't work, I'm going to go somewhere else and get a different antibiotic.Whereas if we had that built in responsibility to follow it up, then the difficult cases don't get lost and go somewhere else and go through the same process.
So follow up appointments is 1 post treatment I guess.I think we're all getting a lot better at this, but we used to be confused about UTI management and I've seen this, that either we don't get them to come back at all or we do come back and maybe we even spend the money to culture the urine.
But that's actually, we don't need to do that for those UTI patients.We just need to get our UTI patients back.Say they've had their course of antibiotics.It was a five day course because it was an uncomplicated sporadic course.We get them to come back day 5, they're fine.That's the end.
Don't look at the urine, don't culture the urine because if you culture the urine and you find bacteria, what are you going to do?You're just confused.It's better just to not look at the urine at all.So I guess my, my key thing is look at the patient when you're following up and not necessarily the urine because that's going to.
And and as they come back and they still clinic little and then you and then you go, OK, well, this the bacteria is relevant maybe now our culture, yeah.Yes, yeah, if if the patient still has clinical signs, you just treat them as if they've got a UTI again and go through the the thing again.Look at the urine.Ideally we should be sending the urine away if the first stream wasn't successful.
So at a individual vet lesson, the best thing we can be doing post treatment is looking at our patient.And I know we can't always do that with our scheduling.Maybe we're not working at that time, but if at least we have a plan, if we're not the ones that's going to see it, a plan of action for that patient, that can help as well so that they're not kind of pinballing between different vets and different antibiotics.
I actually forgot to ask earlier.We talked about draft resistant rates.As far as we know, with all the caveats in place for Australia, is it similar, do we know in the US and the UK and the places where most people listen to this podcast or worse or better?I guess most countries are slightly higher than Australia.
So as I said, it's kind of 10%.Other rates are 25 to 30%.I know Japan published that theirs was 30%.The UK off the top of my head, I think I would have remembered if it was hugely higher or hugely lower.I do feel it's around the 10 to 20% mark.
Where we are different is in Europe and Germany and Scandinavia.They tend to prescribe less.So Germany.Germany enacted a rule that you could not prescribe A fluoroquin alone at all unless you had a culture and they did that a few years ago.
And it has shown some effect in reducing resistance rates.Only small say 8% versus 7%.But yes, Germany you can't describe in refloxacin unless you have done a culture.Can we double click on that quickly?
I'm aware I've heard that fluoroquinolones and potentially beta lactams are worse for creating resistance.Is that right?Or should we avoid them more?Or how do we handle that information?Well, the bottom line reason is that they are critically important for humans, but the reason is that they broad spectrum and they treat life threatening infections with humans.
So that's why they're critically important.The reason why they broad spectrum and the reason why they can select for resistance is how they work.They work by inhibiting DNA synthesis.And so obviously every bacteria has DNA that needs to be synthesized and that's why they broad spectrum and that's why they can select for resistance because they're messing with DNA and everybody has DNA.
So any bacteria could have some kind of DNA mutation that occurs under the pressure of fluoroquinolones.So you're right, fluoroquinolones of the classes do seem to select for resistance at a higher rate than other drugs.
All right, you mentioned using guidelines to make decisions on best choice, lowest tier choice, and duration.Which ones do you like?Where do people go to get this information?There are there's kind of two repositories which are available internationally, so there's country specific ones for Australians, but they can use be used everywhere.
The Australian Veterinary Prescribing Guidelines, there's a website for that and there's the AMR Vet Collective, which is a learning resource.It's actually really great if you're like, you know what, I just, I don't know much about poultry, tells you all about poultry diseases as well as how to use antibiotics in backyard chickens.
So those are two great resources.The ones I like are the East Cade guidelines personally.Which one do I?Eat E Cade International Society for Companion Animal Infectious Disease.The reason I like them, I guess, is that they're they take an international look at things.
So it doesn't matter where you're practicing.They're kind of a general overview of best practice.And they are slowly working through the body systems, their body systems based.So some skin disease guidelines just got updated a couple of months ago.They've come out and respiratory disease, urinary tract disease, but any and all of these guidelines are available.
Add these two repositories and it just depends on like which kind of website you think looks attractive because they're both great.That's been epic.I I love these conversations.They they shift my perspective every time.Is there anything I haven't asked that we need to discuss GATE specifically to celebrate AMR week?
Do we celebrate it or acknowledge it?No, I think we, well, you know, I think we should celebrate it because I don't want everybody to have the really guilt experience that I had of contributing to this epic infection.If we celebrate, we're doing good in the fact that at least you and I are talking about this, that's a good thing.
Celebrate it and look out for the guidelines.If you're working in Australia for the wildlife AMR guidelines, they're going to be great.They're coming out next week.And just thanks for talking with me and I'm sorry if I went to down the nerd pathway here.I can do that.So I call the listeners to the Red Vault, like to the clinical stream, the Red Vault nerds.
That's because the website where you sign up is VVN, which is actually for Red Vault network.But I thought that's too boring.So I say we're we're all a bunch of nerds.If you into something, you know, by classification a nerd.So I'd love nerding out of stuff.So thank you for nerding out with us about antibiotics.
Thank.You.It's been a pleasure.Before you disappear, I wanted to tell you about my weekly newsletter.I speak to so many interesting people and learn so many new things while making the clinical podcast.
So I thought I'd create a little summary each week of the stuff that stood out for me.We call it the Vet Vault 321 and it consists of three clinical pearls.These are three things that I've taken away from making the clinical podcast episodes.My light bulb moments.Two other things.These could be quotes, links, movies, books, a podcast highlight, maybe even from our own podcast.
Anything that I've come across outside of clinical vetting that I think that you might find interesting.And then one thing to think about, which is usually something that I'm pondering this week and that I'd like you to ponder with me.If you'd like to get these in your inbox each week, then follow the newsletter link in the show description wherever you're listening.
It's free and I'd like to think it's useful.OK, we'll see you next time.
Dr Kate Worthing