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Practical approaches to AMS in exotics practice

A video on practical approaches to establishing AMS in exotics practice by Joanna Hedley.
We’ve already talked about some of the issues– the antibiotic resistance building up, particularly with overuse of enrofloxacin in exotic pets. And we’ve mentioned that antibiotic therapy is most effective when it assists the natural defence mechanisms, rather than acting as the sole means of infection control. And I’d like to look at more adjunctive treatment options we can be using and correction of predisposing factors. So basically, looking at the bigger picture. And just as a bit of an example, here I’ve got a case we see quite commonly. A six-month male entire rat presented to us for sneezing and ocular-nasal discharges. Otherwise, examination was pretty unremarkable. Now, I think most of us would be agreed on this case.
It is most likely an upper-respiratory tract infection. And traditionally, most vets would be quite comfortable prescribing a course of antibiotics and sending this animal home. However, if we’re looking at our antibiotic use in a bit more detail, we probably need to consider adjunctive treatment, predisposing factors, and whether antibiotics are definitely indicated for this case at all. And to start with, as I mentioned, we really need to look at the bigger picture. We know this is an upper-respiratory tract infection, or at least suspect it in this rat. And we know the most common cause of respiratory infections in rats is usually the bacterial infection Mycoplasma pulmonis.
This is almost always involved in rat respiratory infections, but it’s usually something we manage rather than cure. And this is important to understand, both when it comes to prescribing options for us, but also in terms of tailoring the owner’s expectations correctly. To start with for this case, I would always want to make sure I have the full history. Often, Mycoplasma has been present for some time, and signs have just flared up due to a recent stressful event. For example, in this case, a new companion rat had recently been introduced. So this rat was under stress. Its immune system was struggling. And the respiratory signs had flared up. In other situations, we may have husbandry deficits.
For example, the enclosure may be poorly ventilated or the bedding may be particularly dusty. So these are all factors we may need to deal with if we’re going to properly eliminate this problem. Equally, if signs are mild, it may be a case that we just deal with the husbandry factors and reducing stress. And in this case, that was all that needed doing. But in more severe cases, signs may not resolve until we have more medical treatment on board. In terms of medical treatment, options could include non-steroidals, which we’ll often use just to reduce that inflammation and improve the rat’s general demeanour as well. Nebulisation, either with saline or with a dilute antibacterial, such as F10 disinfectant, or even mucolytics.
And again, in milder cases, we may just manage the situation with non-steroidals, with nebulisation, rather than using systemic antibiotics at this stage at all. Obviously, in more moderate to severe cases, antibiotics will need to be used. But if we’ve addressed the whole picture, then hopefully we won’t need to use them every time the rat has flare-ups because we will have already corrected the husbandry, reduced causes of stress, or at least helped the owner recognise them. And have alternative treatment options in place to help support the rat’s local immunity, such as nebulisation and mucolytics. Only at this point would we consider systemic antibiotics. However, we will need to use antibiotics in many of these animals.
And we always need to make sure that we are aware of which antibiotics we can use, and that we are aware which dosage should be used. And there’s many resources available for that. I’ve pictured just some of them, here. But I would always make sure that you have the most up-to-date textbook or formulary, as often, dosages are changing as we find out more about the action of different drugs in different species. Alternatively, there’s plenty of online resources or even mobile phone apps, nowadays. So lack of knowledge should never be a problem when it comes to drug doses. However, it is important to understand some common interactions or some common side effects of drugs in certain species.
And the classic ones would be the effect of certain antibiotics in small herbivores. And I’ve pictured them, here– the rabbit, the Guinea pig, that chinchilla, the degu. But also interestingly, hamsters, although not technically a herbivore, also seem susceptible to certain oral antibiotics. These antibiotics, if given by the oral route, tend to cause a reduction in certain intestinal hind-gut-specific bacteria, allowing the overgrowth of others– the classic dysbiosis situation. The bacteria which tend to overgrow are the Clostridial species, which usually end up producing toxins which can rapidly cause the death of that individual. It’s therefore really important when treating these small herbivores and hamsters that we are aware which antibiotics are more likely to cause these problems.
And the way we try to remember these is by a very simple rule, which we call the PLACE rule. The PLACE rule is basically just the antibiotics we never give by mouth to these species. And that’s the penicillins, the lincosamides, the aminoglycosides, cephalosporins, and erythromycin. Now, some of these antibiotics may be given by other routes. For example, in rabbits, we may use procaine penicillin injections by the subcutaneous route. But we take great care to ensure that they don’t ingest any of that. Aminoglycosides may be used topically. Potentially, they may not have such severe side effects orally, but they don’t seem to be well-absorbed. And we wouldn’t be using them by that route in any case.
So there are exceptions to this rule, but generally, these are the antibiotics I would be avoiding by the oral route in small herbivores and hamsters. And if you are considering giving them by any other route, I would always check in a textbook or formulary, first. So then, once we’ve looked at the ones that we can’t use, we have another acronym to use to come up with the ones that we can use in small herbivores. And this isn’t quite such a neat rule. But the first letters of these antibiotics spell out Medications For Treating Small Mammals. And we know that we can use metronidazole, fluoroquinolones, tetracyclines, sulphonamides, and some macrolides in these species.
Again, if you’ve not used a particular drug in a particular species, do always check in your formulary first in case there is a random species-specific reaction. But generally, these are the groups which we’re using most commonly in small mammals. Thank you for listening.

In the video above, Joanna Hedley focuses on how to tackle AMS in exotic pet practice, and where the areas for improvement are. She also explains some handy guides on knowing which antibiotics to use and when, for small mammals. In step 1.17, she mentioned the challenges in achieving good antimicrobial stewardship within exotics practice, and here, these challenges are addressed.

When presented with a case that you would usually be comfortable prescribing antibiotics for, you need to have the confidence as a clinician to consider adjunctive treatment, predisposing factors, and whether antibiotics are really indicated. Always have an up-to-date formulary to hand.

Consider your own practice and the ways in which it has sought to adopt antimicrobial stewardship. What key ideas from this video do you already use in practice, and what have you learnt that you could introduce to your colleagues? Discuss in the comments section below.

Please find a downloadable copy of the PowerPoint slides used in the video in the downloads section below.

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Antimicrobial Stewardship in Veterinary Practice

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