[00:00:02] Introduction: Welcome to All Cats Considered, a podcast from the Feline Veterinary Medical Association.
Here we interview professionals from across the veterinary world and take deep dives into the latest evidence based research developments, studies and guidelines that improve feline health and well being.
We are the home for veterinary professionals seeking to enhance the care of cats through high standards of practice, continuing education and evidence based medicine. In each episode you'll hear interviews with a variety of experts in our field covering a wide range of topics and the latest developments in feline health. We'll share the key points you need to know to improve your patients care.
Let's dive in and listen to this week's experts.
[00:00:44] Yaiza Gomez Mejias: So we've got Giulia Cattaneo, who is a senior clinical training scholar of small Animal Medicine and Katie McCallum who is a RCVS recognized specialist in small animal medicine and a European diplomat in small animal internal medicine as co-director of the Junior Clinical Training Scholarship Program as well.
Thank you, thank you very much for joining us today and thank you very much for this really helpful review for feline enteropathogens and molecular diagnostics and it's their benefits and limitations and clinical applications.
So what motivated, so what motivated you to write this article and why did you choose feline enteropathologist?
[00:01:30] Katie E. McCallum: I guess I can start. So I was actually invited to review this subject by Sam Taylor. So I work with Sam on the University of Sydney feline medicine course.
So I'm a huge feline medicine fan and Guilia is my resident and actually I was due to be going on maternity leave about three months after Sam sent the initial email asking me to do the review. And I was like I'd love to do it. Like publishing in JFMS is like a huge like goal for me. It's the first time I'll have published in JFMS. So I'm really excited about it and I really wanted to do the subject as well, but I was just a bit imminently worried about the fact that I was due to have a baby and like could I like manage all the deadlines and things? I thought, you know what, I'm going to ask my, my resident Gulia, who's also massive cat fan, whether she wouldn't mind helping with and we started doing it and I think it's one of those subjects you think it's only a clinical review. I mean how long, how long is a piece of string? It won't take that long to do. But I think what we've ended up with is a 20 page, almost like a book chapter.
Wow. On feline and because once you start unraveling the subject, it is actually a minefield.
What we found was that although there is a load of literature out there for this subject, there isn't actually any good source that sort of brings all these studies together in a meaningful way. And that's what we aim to do. We wanted to try and sort of tease apart what is, what should we be testing for, when should we be testing, why should we be testing, and all of those important questions for a general practitioner in their daily practice, really.
So what we try to do is summarize all the information that exists and then actually talk about why sometimes it's not that useful testing.
And I guess the clinical relevance for me is that when we get cats with diarrhea coming in for referral, quite a lot of them will have had these extensive fecal PCR panels doing.
And I've actually become a little bit blase, dare I say. And I, I look at them and I think there's a few odd positives. But you'll find that vets will, will sort of follow that positive and potentially treat those cats, and then they'll repeat those fecal analysis and the results will come back positive, positive, positive each time.
But the cat's still got diarrhea. And you think, hold on a minute, is that actually significant for this cat, or are we just picking up something that isn't actually clinically a problem?
So that's kind of my side of things. Julio, would you like to add anything to that?
[00:04:08] Giulia Cattaneo: Sure. So I guess the other, other thing, the other main focus for the paper really was, you know, other than the interpretation of a positive result, testing is not inexpensive. So it's useful to consider, you know, which cases you're going to test, what are you going to test for, for, and what's the best detection method for that particular pathogen, which I think was a little bit so hazy when we started this review, and that's what we wanted to pick apart. And ultimately, if you plan those things, if you plan, you know, who you're going to test, when you're going to test, and what you're going to test for, that should hopefully make interpretation of results a lot easier, or at least that's the hope. And as a starting point, we really wanted to identify first and foremost which pathogens are important in feline enteric disease, which ones should we be concerned about?
And we've described these in our big table, which took a long time to make, but we're very pleased with ultimately.
And the table also includes preferred Detection methods. Although it's important to note that all of these things need to be assessed on a case by case basis as well. And we also wanted to touch upon, you know, inappropriate treatment choices, the use of antibiotics, and I'm sure we'll discuss that in more detail a little bit later.
[00:05:31] Yaiza Gomez Mejias: That's great. Those are very relevant reasons. I always find funny how in our profession, our profession is so influenced by the availability of new methods, the new diagnostic methods and the way it works. It works a little bit like, okay, we've got this method, now we have to learn how to use it and now we need the evidence around it. Whereas rather than. And sometimes we find ourselves in a place where rather than justifying why we do a test, we have to justify what. Why we should not do it.
[00:06:05] Katie E. McCallum: Yeah, yeah, that makes sense. Yeah.
[00:06:08] Yaiza Gomez Mejias: And is that dynamic that keeps the professional evolving as well? Like it's a little bit of, it's fun. So we know that microorganisms are part of the, of the gastrointestinal tract and that they contribute to make things work.
When do they cause enteric disease?
[00:06:28] Katie E. McCallum: This is the part of the paper that has been quite challenging. What we wanted to do is, as I said, there is a lot of literature out there and a lot of prevalence data out there which will look at cats with diarrhea and cats that don't have diarrhea and they'll try and ascertain whether there's a higher prevalence in the cats with diarrhea.
And that's all very well, but then you have five or six of these studies with different populations of cats, different detection methods, making the whole thing quite difficult. So what we aim to do is to, to get prevalence data and combine it all. And what that ended up showing us was that the prevalence in diarrheic cats was very similar to non diarrheic cats. But obviously with the caveat that by combining all these studies there's lots of different factors that we haven't taken into account.
So I think the problem that we've got with enteropathogens is so many of them are subclinically shed. So the clinical relevance of them is not known for all of them.
What we do know is there are some risk factors that have been sort of reported in multiple studies.
The big one is sort of your shelter, multi cat household, a situation where you get outbreaks of diarrhea. And that's probably because you've got stressed cats. There's high disease burden and exposure to disease, high housing densities, lots of movement of cats in and out as well, and concurrent diseases as well. So I think when you, when you have lots and lots of cats in the same place, particularly with diseases, let's, let's mention coronavirus, for example. The prevalence of fecal shedding of enteric coronavirus hugely increases in a shelter cap setting in most, most situations.
The other thing that has been looked at is seasonality and we actually only found one study looking like in any great detail about seasonality. And we didn't find it particularly clinically useful in that they looked at sort of are there peaks of bacterial protozoal viral infections depending on the season. And I don't think that makes a big difference to how I would approach a case.
Other risk factors are diets. And I'm going to bring up raw feeding and I'm going to do it very carefully.
Raw feeding is something that, that is quite up and coming. There's a lot of owners raw feeding their cats. Now we know there has been a link with raw feeding to certain enteric diseases, including salmonella. And there's also more recent paper showing that cats fed raw diets have been showing shown to get tuberculosis as well in the UK.
It is a contentious subject because the problem is you can't actually prove causality. Just because they're having a raw diet doesn't mean that the salmonella has necessarily come from that. It might just be increasing these cats exposure to these diseases rather than actually being the true cause of that. So I'm going to leave it at that. But I just think that raw diets do need to be looked at because some of them do carry a zoonotic risk as well.
And the final risk factor that I want to talk about before moving on to Julia is just age.
If I have a young cat presenting with diarrhea, I'm much more likely to do infectious disease testing than an older cat because their immune system isn't as well developed. They have a lot more stresses, they have vaccinations, neutering. As I said, their immune system isn't as developed. They're much more likely to pick up infection.
[00:09:58] Giulia Cattaneo: And from my, my side of things. So of course breed or genetics is important. If we take for example Tritrichomonas, this is a pathogen which we see more commonly in our pedigree breeds. So Bengals, Persians, Siamese, Abyssinians and so and often these are the younger of the younger spectrum as well. So something to think about why this disease affects pedigrees. It's still a little bit hazy, but Certainly can help hone in our diagnostic methods and choose the best, you know, the best testing for these individuals with regards to health status. You know, again, going back to immunosuppression, increasing the risk or the propensity to develop clinical signs in, you know, in cats that maybe were previously asymptomatic shedders or carriers of these pathogens. And it was interesting as well to look at interactions between pathogens. So co infection law, potentially we should term them as CO carriers. But for example, Cryptosporidium and Tritrichomonas can have potentiating effects on each other in terms of disease.
And then looking at general gastrointestinal disease and general GI health, we need to think about, for example, clostridial bacteria for the forms that they might lie dormant. So in the spore form and also the vegetative form which is actively growing, and different microclimates in the GI tract might allow these clostridial bacteria to convert to that vegetative form and essentially then cause disease. We know that and I'll talk about this a little bit later on, but increased concentrations, for example of primary bile acids can help shift from the spore form to the actively growing form. And so that's, you know, the favorable intestinal conditions might shift towards disease.
Antibiotics are another big factor at play. They can lead to dysbiosis and therefore shifts in competition by originally commensal bacteria are wiped out and then potentially allowing propagation of bacteria that are pathogenic or opportunistic and then chronic inflammatory enteropathy. We have disruption of the normal GI barrier potential then for development of disease by pathogens that, you know, would otherwise be kept at bay with normal barrier. And we know that with chronic enterprises potentially there is a genetic basis. So for example in dogs, tlr dissecting patients. So lots to think about for sure.
[00:12:31] Yaiza Gomez Mejias: Yeah. And a lot of relevant things that you've mentioned that can be, can be informed or can be found out during the history taking.
Thank you for that.
Once we have identified all these risk factors, what are the general indications for testing cats for enteropathogens and when is testing not worth the effort?
[00:12:57] Katie E. McCallum: Well, I would first of all say that they have for me, they have to have diarrhea. Really in a clinical setting, an individual cat needs to really have diarrhea before I'll start testing.
I don't know if anyone's actually really kind of looked into sort of these cats that have got chronic diarrhea, but then they have like intermittently normal feces, whether there's A head, you know, a difference in results on those days where they have normal feces. So I can't say for sure, but I think if they've got raging diarrhea, then I would absolutely test if they had normal feces. I would try and encourage the owners to. Because there's a. There's a big push quite often that the owners might bring in a sample when the cat comes in for its vaccination. And she mentions at the time that there's been a history of diarrhea, but she brings in a sample and it's either got a big firm poo in it and you're like, oh, I don't know what to do with this. Do I just say thank you and give it back to her? Do I take it? You always look very gracious anyway. But the other thing is they've often caught loads of like. It's got loads of like cat litter in it as well. And you're like, this is. I think there's some, there's some indications that cat litter can also like inhibit some of these organisms as well.
So for me, if, if some, if an owner is really worried about diarrhea and they brought me in a firm poo, I'll say, can you. Thank you very much, but can you go home and can you get me. I'm very greedy. I want three samples, if possible, in pooled samples. So ideally done over one or two days. And what they can do if, if they're happy to, is they can put them in the fridge while, while they're getting all three of them, if they're happy with the biosecurity and in a bag or something, something quite a good container. And then they bring them in to me and then I will send them off, I'll make, I'll pull them together and send them off because you do get this intermittent excretion of organisms. So I want to try and maximize my chance of getting a positive.
But it's not just a cat with diarrhea I've got to think about actually. Is this just an acute diarrhea? Is this the first time this cat's ever presented with diarrhea? Is it going to just respond to symptomatic management? Maybe I'll suggest a digestible diet.
I might suggest probiotics. We'll talk a little bit more about that later because that again is one of those subject areas that there's some controversies in as well.
So if it's mild and self limiting, I probably wouldn't test.
So if it's been going on for two days and it stops. I definitely wouldn't test for that because a positive result in this situation would not change my treatment plan at all.
What other situations would I test?
I would probably look at then at my risk factors. So I would look at my individual cat in front of me and think, well, is this cat likely to be exposed to an enteropathogen?
So is it for a multi cat household or has it recently been in a cattery or they just rescued it from a shelter?
Or do you have a history that multiple cats in the household are affected as well? Or dare I say if the cats are all fed, it would probably make me more likely to test for enteropathogens as well. So that, that will be another situation that I'd be or sort of another aspect of the thought and the decision making process.
Then I would think about the, the actual patient in front of me and how well they are.
So what I mean by that is that certainly I think this is a big area of interest, particularly in canine medicine where they've actually come up with some guidelines to when or when to use antibiotics and canine diarrhea. So the Novac guidelines, which I think are EU based and what they've said is that they don't recommend antibiotics unless you've got very severe diarrhea that's not responding to supportive treatment or cases that have got high risk of bacterial translocations. Maybe those patients are pyrexic, they've got a neutrophilia, that sort of thing, or they've got bloody diarrhea. Then in those situations I might reach for antibiotics. But I would also want to test those cases first if I could. So that's another situation that I'd consider antibiotics, consider fecal testing.
What else to think about is the timeline I mentioned about the acute cases that I wouldn't test for. But if this was frequently recurring or chronic then I would definitely, particularly before embarking upon a chronic enteropathy workup.
It's a little bit embarrassing if you send a dog. Dog, sorry, I did not mean to use the word dog in a cat podcast. If you send a cat for upper and lower GI endoscopy and you find Tritrichomonas on the histopath or something that that's less than ideal, isn't it? You know, because that cat could have responded to a course of antibiotics. So that's another. I'd get a baseline fecal result before I embarked upon more invasive diagnostics or if I diagnosed a Chronic enteropathy. And that patient all of a sudden deteriorated. It was on a nice diet, a hydrolyzed diet for six months. And then all of a sudden it got unwell with bloody diarrhea or something.
Then I would consider actually retesting FE sometimes actually dysbiosis or an infection on top of chronic enteropathy can actually basically destabilize them for, for whatever reason I test those cases.
We used to use a lot of fecal culture and microscopy and I still do a lot of, I do a lot of fecal cultures and microscopy is my initial testing.
But if that's negative and I still suspect there's something infectious or there's a specific infectious organism I want to look for, then I perform PCR. This is a particular, a particular example of this would be Tritrichomonas fetus where we know that routine culture doesn't, it doesn't get cultured by routine culture. If you want to culture Trina Trichomonas, you have to order in some sort of specific culture medium from the states. And when you've got a cat in front of you, that's not something you can deal with very, very quickly. So I personally do a colonic wash and PCR, which has got very high sensitivity. So I wouldn't even consider culturing for Tritrichomonas at that point. So I would do Trichomonas for that one anyway.
Finally, if there was a concern for zoonotic disease. So if I was dealing with a raw fed cat or if my owners were immunosuppressed and they were on chemotherapeutic treatment, or they were elderly and their cat had quite significant diarrhea, then I might be inclined to do fecal testing at an earlier stage than I would normally do just to make sure that there's not a risk of potentially transmitting that over to them.
So that's the sort of cases that we would test in terms of diarrheic animals. But Guilia, would you ever test any non diarrheic animals?
Yeah.
[00:19:51] Giulia Cattaneo: So I think this goes back to, you know, consideration of monitoring in outbreak situations. This might be in shelters, catteries, multi cat households. I think you can obtain some really good information from that. Even that though they're asymptomatic and try and put preventative mechanisms in place. But also there is a, I would say a place for serial testing in treated patients where you want to monitor for resolution, persistence or potentially reinfection, which again is common in multi cat households. For example, having enteric coronavirus to name one.
So I think the main difficulty with this approach is what do you then do with this information?
If a patient in a household has persistent positive results, are you going to treat them? If they have a resolution of clinical signs, it's difficult to then justify that reasoning. I know that there's a stimulus, or at least I've certainly had owners asking, you know, can we treat Mari cat that is shedding feline enteric coronavirus that is asymptomatic with the GS441524? But actually, you know, we are then, are we then pushing towards resistant strains if we overuse that medication?
So I think sometimes testing in these situations opens almost a Pandora's box and you need to be, you know, quite careful with, with the advice that you give. But certainly for monitoring, for research purposes, you know, testing is, is a really, really good technique and I guess also might help with putting biosecurity measures in place. And it also translates, translates quite nicely to zoonotic diseases and in immunocompromised donors.
And then I guess another emerging practice would be to screen donors for the Fecal microbiota transplantation, which is a fairly recent technique. It's the focus of quite a lot of new studies, mainly in dogs, but there's a few in cats as well. I mean, the support for this practice is lacking. We did read up on a recent study published actually January 2025, but that showed that single enema FMT didn't necessarily lead to significant improvement in both the dysbiosis index and the feline chronic enteropathy activity index, encapsulated chronic enteropathy compared to their respective controls. But then there's also a lot of talk about, you know, how do we standardize these protocols, how do we actually administer it, how frequently do we administer it? You know, it's not the case. It's probably not the case that we administer it once or twice and then, you know, it should exert its effect. Does it need to be more of a chronic administration?
And also deciding which patients undergo this treatment is also challenging. I feel like we probably fall back on it as a last resort in refractory cases. But if we're using it on refractory cases, which this might underlie the lack of response that we see in the literature, if they're not going to respond to the conventional methods, is it less likely that they will respond to FMT or should we be using them as a fast line, for example, with, say, diet as well? But still lots of Questions that are unfortunately, well, remaining unanswered.
[00:23:06] Yaiza Gomez Mejias:: Well, thank you. Thank you for bringing that up because I see it's quite a popular procedure among certain practitioners and every time this topic comes up in the forum, in the ICACARE veterinary forum, we haven't got enough evidence to support any decision making.
[00:23:24] Katie E. McCallum: So.
[00:23:24] Yaiza Gomez Mejias: So it's great to know that you're working on it.
And about something you said before, Katie, you mentioned Tritrichomonas and you mentioned that you flush the tract, the gastrointestinal tract. There was a paper from a good few years ago where the possibility of using something to scoop out the content might be useful too. How do you.
How useful do you consider both techniques?
How reliable or how. I mean, it's linked to my next question about limitations and benefits as well.
When you do a sample, when you send a sample for pcr, obviously the way you obtain the sample matters. What do you think about the particular.
[00:24:12] Katie E. McCallum: I mean, it's probably a running joke at work. How few cases of Tritrichomonos fetus I diagnose.
I get very excited when I get a cat that comes in with chronic large intestinal diarrhea. If it's a young and pedigree cat, I'm literally so excited because I'm like, it's going to be Tritrichomonas. This is my, this is my moment.
[00:24:32] Yaiza Gomez Mejias: Because, oh my God. I haven't met any. I haven't met many people excited about the cat poo.
[00:24:39] Katie E. McCallum: Yes. Yeah, well, that's me. But like, it's one of those ones where, because you read through the vet's history and it's probably, unless you're looking for it, you're not going to find it. So I always think that these are the ones that we're more likely to diagnose in referral practice.
I don't. I'm trying to think of how many cases of Tritrichomonas. I've diagnosed and I would say it's very few.
So that begs the question, we do colonic washing here. It's what I'm used to. It's the equipment I have.
And I guess there is a small chance that maybe my technique or my sensitivity is not actually as good. Because, I mean, nothing. No, no, no. PCR technique in these cases is probably 100% sensitive.
So I probably am missing some of those cases. We have in suspicious cases, we have repeated PCR on multiple occasions and still not had any positives. But I think there are definitely other studies to show that there are some comparable techniques. So maybe that is something that we need to think about at the vet school.
Whether we try some different techniques and maybe run them alongside each other and see if we can prove the superiority or at least the non inferiority of one procedure to the other.
[00:25:50] Yaiza Gomez Mejias: Yeah, yeah, I just mentioned the paper because it came to my mind right now, but I don't know how reliable that paper was or where it came from, I don't know. But it's interesting because I haven't had many Tritrichomonic cases either and I always wonder what's the best, you know, what's the way to optimize the results of the, of the diagnostics tests I run. So apart from these limitations of this particular way of sampling this specific disease, what are in general the benefits and limitations of molecular diagnostic methods, especially PCR for feline enteropathogens.
[00:26:26] Katie E. McCallum: There's quite a lot of benefits and I think PCR techniques have been around for quite a few years now and they're very much a helpful, I would say they're more helpful than a hindrance for sure. In my daily life I, I love a pcr. I love testing for things. I'm one of those medics that I won't pragmatically sit down and think, well, what is most likely. I love, I love a good test because sometimes you get a positive. Not in Tri. Trichomonas cases though. But yeah, no, no, that I've got good reason for doing it for sure, I promise.
But yeah, with regards to pcr, mainly because that's the focus of our subject or our review, is a sensitive and specific technique, which is a good thing because you're more likely to pick up a organism than for example, culture as we've mentioned with Tri Trichomonas. So first of all it's a sensitive technique. So that Julia will tell you that in some respects can be a downfall, but it is a sensitive technique. So if you're looking for something, there is a chance that you're going to find it on pcr.
That's a benefit for me. The other thing is there are some organisms that are less likely to be able to be cultured. So for example, we don't routinely culture viral organisms for diarrhea. So you can get some viral PCRs that will allow you to diagnose viral infections.
Not something we do routinely, but just more in experimental work. For example, you can also use quantitative PCR which can be useful to detect the actual load of organism that you have and monitor the response to treatment. That's particularly important with Things like coronavirus when you're looking at shedding cats and whether you get a reduction in shedding over time as the infection pressure decreases as well.
The other thing is that we talked about fecal PCR and we talked about the fact that they come as a panel.
So practitioners love it because you can test for sort of eight or nine different infectious diseases with one sample.
So it's convenient. And also you just have to send it to one commercial laboratory at one time.
It's easy to submit the sample because it doesn't require specific freezing, couriering, transport medium, for example, and you only require a tiny, tiny amount of genetic material for it to be useful. So in terms of practicality, it's really, really easy for general practitioner to get that sample and to send it off.
The other thing is that you can PCR not just species, you can also look at other areas or other fluids, for example, you can do abdominal fluid to look for coronavirus, you can look at vomit to look for panleukopenia and blood if you're looking for sepsis, for example, in salmonella cases. So you can also use multiple sources to get your diagnosis as well.
And then the other sort of nuance of PCR is that we're starting to get some, like even more advanced PCR techniques where we can actually PCR for genetic material for the actual toxin that like for example Clostridium CPE toxin. So we can actually look and say, well, actually this, this animal is producing the toxin, the enteropathogenic toxin of this, of this bacteria is that more likely to be relevant, relevant in this cat. So that's also quite useful. And finally, both PCR and fish you can use on formalin fixed tissue.
That is a particular advantage. What I would say is that I've been in a situation multiple times where for example, one of our residents has taken a lymph node in a, in a cat with diarrhea. It's got a big enlarged lymph node and they've taken a sample for culture. So we've a fresh sample for culture and a sample for histopathology and they haven't frozen a sample for pcr. And it's happened a few times. And it's because if you don't specifically ask for it, it's. It's one of those things that quite easily gets forgotten.
And PCR doesn't run very well or as well, informal and fixed sample. But fish, for example, runs really well, informal and fixed. And you can do PCR and formalin fixed, but it's not as, as great.
So for example, if you've got a mycobacteria case that again, it's one of those things, one of these elusive things. I don't ever get zeal Nielsen positive cases, but if I send that off for PCR and I've got pyro granulomatous inflammation, I often will get mycobacteria. So just again showing you that the combination of complementary techniques in these cases can be really useful. So you've got, you look at your sort of your histopath and then that might help you guide you into what infectious disease you might be dealing with and then you go on and do PCR and that sort of thing. So I love pcr, but Julia is going to tell you about the limitations because she's going to be miserable.
[00:31:28] Yaiza Gomez Mejias:: Thank you for the reminder and thank you for reminding us to keep a part of the, of the tissue for frozen for.
[00:31:35] Katie E. McCallum: I also blame the residents, which wasn't fair because kind of I ultimately have responsibility for those cases. But sometimes it was a Friday afternoon and you don't specifically say please freeze some. Then you'd come in a Monday and.
[00:31:47] Yaiza Gomez Mejias:: It's like, no, no.
[00:31:51] Giulia Cattaneo: Yeah, that's definitely happened. But no, I guess in terms of limitations, I think the main thing, and I think Katie and I both shudder when we hear the name Foster because we must have spent hours and hours trying to figure out which clostridial species are actually important, which ones even of say Clostridium perfringens, you know, the CPE toxin. We know that a lot of cats carry it anyway symptomatically. So what can we actually gain from a positive result? I think it's still a little bit hazy, but definitely I think we have to be careful because if we are testing positive for, for whether it's specific genes or specific pathogens, positivity does not equal causality and hence why I think only testing in cases where it's indicated to do so and not just blanket testing helps a little bit to narrow down the significance of results and improve interpretability of results and also co carriage of other pathogens if they're positive for more than one disease. You know, what, how do we interpret that? You know, are they both causing disease? Are they, are they both just, you know, being sheds or carried asymptomatically? Again, it's, it can be quite challenging and there's not necessarily an easy answer every time. And I guess the other thing as well that we need to remember is that PCR does not necessarily distinguish between live and dead pathogens. And so I know that in human medicine, human labs, there are some very specific or specialized PCR techniques where they try to distinguish between live and dead organisms on pcr, but it's not something that we have available to us, you know, readily. That's something that I've seen described in veterinary medicine and certainly not something that's commercially available.
So again, we need to maybe use other techniques such as culture, which might help us then to determine whether we have, you know, actually live, live pathogens growing. And again, touching on what Katie was saying before, you know, time, point of testing, some of these pathogens are sheds intermittently. So, you know, if we test at a point where they're not shedding, we might get a false negative result. But also if we test too soon in the disease process, again, we might get a false negative. And so again, we need to choose, choose our battles, really, and test at the right time if we can. And on the glitch side, for example, with panleukopenia virus vaccination, recent vaccination, two to four weeks, for example, could cause false positive results and then send us down a completely different path. So, again, being aware of these nuances and these particulars of each pathogen, and that's something we really try to focus on. And again, it just means that you need to look at verificators, the whole individual, and pick apart, you know, these. These particulars that might affect your interpretation of results. And I guess another thing as well is the pcr. You know, it's not performed in one single lab, and there's lots of labs out there performing a test for the same pathogen. So we need to standardize these techniques. Obviously, they will use slightly different techniques, slightly different probes on the PCR potentially. And so that can cause some variability in results.
But also on our end, you know, those collecting the samples and then, you know, delivering them out, we need to be careful with how we store them, how we collect them, whether it's an appropriate sample. And again, things like cat litter can cause inhibition to pcr. So then you might get the false negative. So all of those things to think about, and we did, you know, try and try and go through those particulars in the review to help where possible. But I think as a baseline, trying to have a direct communication with your lab to make sure that you've got everything in place to collect the right sample and deliver it as you should, the maximized interpretability of results would be the bottom line, really.
[00:35:47] Yaiza Gomez Mejias: Thank you. Thank you so much. For the overview and thank you very much for writing the review because it's really useful for us general practitioners to have all these things written in a peer reviewed article that we can share with colleagues and read ourselves when we forget half of the things you've said because there's so many to forget. So thank you for putting everything.
[00:36:09] Katie E. McCallum: I've forgotten half the things we wrote.
[00:36:13] Yaiza Gomez Mejias:: It's hard, isn't it? It's a lot of information to keep in.
[00:36:16] Katie E. McCallum: Yeah, yeah.
[00:36:17] Yaiza Gomez Mejias: But it's so important at the same time, especially nowadays when we are so aware of the limitations we have at the moment when we think of prescribing an antibiotic. Could you, could you go through why is it so important to, to, to be cautious at when prescribing antibiotics and to treat these feline enteric diseases?
[00:36:39] Katie E. McCallum: Yeah, I mean this is a very hot topic at the moment globally as part of the sort of one health approach to human, you know, to the link between human and animals. Because we know that there's a move in the, particularly in the European Union for example, to restrict antibiotic use in animals and actually certain antibiotics that we quite, I would say freely use carefully in the sense that I regularly use it, but based on culture and sensitivity, things like fluoroquinolones for example, if we are restricted in using them, then that would be devastating for our ability to care for cats.
So it's a topic very close to my heart actually. But having said that, antibiotic overuse is huge.
There are some studies in veterinary hospitals in the States looking at their use of quite hefty drugs like carbapenems and things like that. And also the link to multi drug resistant bacteria. So it's something not to be overlooked. And in humans, Clostridium difficile infection is almost entirely thought to be due to antibiotic overuse.
So antibiotics are used as a treatment for diarrhea, but can also cause the diarrhea in multiple ways, which we'll talk about in a little while.
In my opinion, the vast majority of diarrhea cases, acute diarrhea cases, will clear up with symptomatic treatment, just like in humans. I mean, I wouldn't go to the doctors if I had diarrhea unless it being on for a little while. Although having said that, I went to Cambodia with my friend traveling a few years ago and she's a doctor actually and we were laughing about, she came home with, well, she was really unwell towards the end of the holiday and we were kind of laughing about her having dengue fever, because, like, that's very unlikely, blah, blah, blah. And then she got back and she was on call as a doctor and she was like, I had to call him sick for the first time in my career.
And they diagnosed her with dengue fever. So she was actually off with. With infectious cause for ages. So it does, it does happen. But I would say the major. I would. I've never been to the doctor and got antibiotics for diarrhea, so I don't think we should be doing that for cats.
And I think there is a.
I'm hoping there's an increasing understanding from our pet owners that of why we're not giving antibiotics. But having said that, there is a pressure to give something. I don't know if you feel the same, but you've got an owner in front of you and they've spent however many pounds or euros on a consultation and they're like, what, what, what do I do? And if you go. Go home and give it a bland diet, the digestible diet for a few days, it can be frustrating for them because the resolution might take a few days. You're not giving them a magic pill, whereas an antibiotic is perceived as the magic pill. So I personally don't use antibiotics in these cases.
There. There are some probiotics available quite easily. Easily available.
The problem with probiotics, as I've learned from some of the conferences that I've been to, is that there's. Because they're a nutraceutical, they don't undergo the same stringent pharma, pharmacological, sort of. What's the word? Like, they don't undergo the same clinical trials necessarily as, as a proper pharmaceutical drug.
And also I don't think they have to specifically list their ingredients to the same level as you would with a drug.
And because of that, and I think I also went to a really interesting conference once where they talked about the actual strain. I think it was like a strain of Enterococcus PCM that they used in a probiotic and it's based on just like a strain that they cultured from a cat, like yonks ago or something, and they've been using that same strain and all these probiotics and if you're not policing how much you're using and, and there's lots of different ones on the market, but they also contain things like binding agents and things like that.
What are we. Actually, I like to know what I'm giving and it is, it is. You are giving organisms, so it's, it's a bit of a minefield. I don't know how you feel about probiotics, Yeza, but I'm just a bit, I'm still a bit on the fence. There is a study that shows in shelter cats it reduces the duration of their diarrhea.
[00:41:06] Yaiza Gomez Mejias: From what we see, from what we've spoken with the experts we've been inviting to webinars and clinical clubs, it comes across as if we didn't have, we hadn't got enough evidence to really promote their use. But at the same time, it is true that owners demand something and some of them explicitly ask for antibiotics. The number of these clients are very slowly disappearing.
They don't demand, at least here in the UK, where I work in an urban environment, they don't seem to, to demand them as they used to demand them like a couple of years ago. But, and I guess I've got the feeling that I, at least I'm less likely to harm the cat and the, and the universe if I prescribe a probiotic than an antibiotic. But, but it's true that it's, it's quite tricky. And at the same time, with the antibiotics, I understand that we don't, we don't have to prescribe them very often, but when we talk about these cases, when we say these cases, it's difficult to know which case are you talking about, because all these limitations about diagnosing a particular problem, as you said, you may have diarrhea and a really severe diarrhea that prevents you from going to work or leaves you flat in bed for a couple of days. And like it happened to me in Mexico as well. And if you have an underlying problem like a kidney disease or whatever, and you're afraid of getting dehydrated because your kidney disease might get worse, then you're, and you have an acute, then you may take antibiotics in that context, even though you don't, you don't know, you haven't labeled the underlying bacteria or microorganism. So I guess we, as general practitioners, we feel quite pressured by that lack of accuracy in our diagnosing when diagnosing gastrointestinal problems. And, and I, I read a paper not long ago. I didn't go through the, the whole paper, but it was an abstract. It's a very recent paper about the use of metronidazole among general practitioners. And it seems to a high percentage of practitioners seems to be high prescribing metronidazole still, despite not, not having a clear indication for it. But I understand the fear behind failing and causing death or, you know, a severe disease in an animal that you're. That you're looking after.
So, yeah, it's a very controversial, very, very difficult transition time. Whether we are passing that we are living now.
[00:43:39] Katie E. McCallum: Yeah, I think I'm not against probiotics, and I certainly feel like they're the lesser of two evils. And I haven't. I personally haven't seen any significant side effects as a result of giving probiotics. There is one.
I always remember Penny, who used to be my residency supervisor, Penny Watson. She said that there was a paper in HU or a study going on in human medicine where probiotics actually worsened acute pancreatitis. So they had to actually stop the study during it because it was actually becoming more detrimental to give them.
So I guess I think it's just worth having in the back of your mind that you are giving something to the patient, so be mindful of that. But I think holistically it makes sense to give probiotics. We know that with acute diarrhea, there's going to be a disruption transiently of the microbiome, probably due to stress, maybe diet change or scavenging. Maybe the cat's picked up a viral pathogen that we're not going to necessarily test for. So I don't think it's wrong, wrong to give it. And there is evidence it may speed up the resolution. But I certainly think in general, the way that things are going, I think we're moving towards microbiome modulating therapies like fmt, prebiotics, probiotics, and even dietary modification.
Simply.
I don't know what your feelings are on diet trials, but we are getting some really, really good results in cats with just switching their diet. And they're so different from dogs in that they do respond much, much quicker to diet trials and dogs.
Yeah.
[00:45:17] Yaiza Gomez Mejias: What's your experience with diets, Guilia?
[00:45:21] Guila Cattaneo: Yeah, so we often see quite a lot of cat cases when we're both on clinics. But, yes, I think diet can be really quite a powerful tool, both in cats and dogs. And usually it's our first go to. And I think if you've got a chronic enteropathy and you've ruled out, you know, the more common or obvious causes, then I think key diet trials are necessary before then going into things like immunosuppressor and other weird and wonderful things, because sometimes it can be just as simple as switching the diet, and within a couple of weeks, you're you know, you've seen a really visible response, a really positive response.
So yeah, we use it very often and as a, as a hospital really, I really think anyone, unless there are indications to reach straight for immunosuppression or other things, antibiotics, then we, we tend to stand our ground and say, okay, well, let's try a few diet trials and sometimes one is not enough. You need to, you need to try more than one and find a happy medium. But no, we do try and push for that and we're quite good. In terms of broad diarrhea cases, we very rarely use antibiotics.
[00:46:31] Yaiza Gomez Mejias: So we have a lot of tools to replace antibiotics with. I think this is going to be very useful for the Veterinary Society members.
Thank you so much for joining us today. I'm not going to take any more of your time. I think you've done an amazing work with your review and this podcast is going to be really appreciated by the members and also by the audience of the open Access podcast.
[00:47:00] Katie E. McCallum: Thank you so much for inviting us to speak.
[00:47:03] Giulia Cattaneo: Thank you.
[00:47:04] Conclusion: Thank you for listening to this episode of All Cats Considered. We hope you enjoyed this interview. For more information on the topics discussed in this episode, please head over to catvets.com podcasts and explore the links in the show notes.
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