How do you deal with MRSP? Any experience with chloramphenicol?

RE: How do you deal with MRSP? Any experience with chloramphenicol?

Beats — Tue, 13 Jun 2023 13:16:44 GMT

Topical treatmnet does seem to be the way to go in this dog. The degree of healing even after the initial sedation, clipping and heavy-handed hibiscrub use is dramatic from photo provided. A family member is going to assist in chlorhexidine cleaning and some fucidin cream and will then review. It had got clinacin prior to the culture results too and that may or may not have played a role by killing other bacteria other than the MRSP cultured.

RE: How do you deal with MRSP? Any experience with chloramphenicol?

Stephen Shaw — Tue, 06 Jun 2023 07:05:42 GMT

It is obviously a difficult case. I am not sure I would consider euthanasia on the basis of the culture, but quality of life may be another thing.

I would use Pardale for analgesia at 15-20mg /kg BID to TID and not the previously used 10mg/kg.
Ciclosporin has a broad mode of activity and is typically used in these dogs, lokivetmab is narrow and might be good with steroids, oclacitinib or ciclosporin I cannot see this being helpful as a sole agent at this time.

Nuflor; 30 mg/kg subcutaneously every 12 h has been reported in one paper describing the development of florfenicol resistance (see below)

Minocycline and doxycycline susceptibility are not identical as doxy is not a great surrogate

Regarding the lab testing for mupirocin - it is really helpful they are testing, but it would be great if they put that result in the comments or another place as we still see mupirocin recommended inappropriately for cat acne!

Couto, N., et al. (2016). "Acquisition of the fexA and cfr genes in Staphylococcus pseudintermedius during florfenicol treatment of canine pyoderma." J Glob Antimicrob Resist 7: 126-127.

RE: How do you deal with MRSP? Any experience with chloramphenicol?

Beats — Mon, 05 Jun 2023 21:00:37 GMT

Thanks Stephen! That's amazing information!

I've reviewed the previous notes and summarized below with what I have:

Is presumed atopy.

Started with flank itching at 10 months of age. Now 5 years old.

Attempt at food trial in 2019 was not successful.

Managed on low-dose preds (5mg twice daily) up to COVID, then started remotely on apoquel during COVID.

Bit of possible mucocutaneous pyoderma around left nostril mid-2021 resolved with TMPS.

Developed similar on right nostril couple of months later with fissure reported and was trialled on higher-dose pred for possible auto-immune condition. 12.5mg twice daily and after a week the dog was coping very poorly on the steroids (though the nose lesions had resolved). Owner reluctant to use steroids again after this...

Continued on apoquel intermittently, mostly at 16mg once daily when using I think, but was giving up to 3 times daily at one point.

April 2022: flare of possible pyoderma around nostrils again and cleared with TMPS again.

June 2022: some interdigital and hock suspected deep pyoderma - cleared with TMPS. 16mg apoquel twice daily and 4mg medrone daily then worked for large period of time (at least as far as was known).

Late 2022: some new interdigital cysts. Medrone increased to 8mg daily and mostly resolved.

January 2023: sedated and area of presumed deep pyoderma in dorsal proximal tail in area of tail gland - clipped and cleaned and castrated and cultured with Staph pseudintermdius sensitive to everything tested including plain amoxicillin. Apparently resolved with TMPS, but may never have fully resolved.

May 2023: Sedated and horrible area of presumed furunculosis in dorsal proximal tail - clipped and cleaned and cultured as above with MRSP. Weighs 68kg. Has couple of other areas around hocks and interdigitally that could be deep pyoderma, but on much less severe scale than tail, which was awful.

I'm not sure the tail would resolve with topical treatment alone (even if owner was capable of doing this). Reading through this, I'm thinking perhaps a very high tail amputation is not a daft idea, but I am rather nervous about operating so close to the pyoderma on the tail when a surgical site infection could not readily be treated with systemic antibacterials. It would still leave the other areas, but there are not anything like as severe. I wonder about trying ciclosporin or cytopoint instead of the apoquel, but I don't think that would be affordable. I think even temporary resolution (if achievable) for a year or less would be worth it to the owner (if affordable); the long-term outlook is perhaps less optimistic. I was a bit shocked by the MRSP culture (only the second MRSP pyoderma we've seen at the clinic, and the other one came with it from a different area), so my knee-jerk response of thinking euthanasia was perhaps a bit sudden without trying a little further first.

I think endocrine disease is unlikely, but has certainly not been excluded. There's a limited budget here, so I have to be careful what I choose to do.

For pain relief would you add metacam? Apparently the owner can touch around it fine, but would struggle to squeeze out creams and apply etc. Perhaps should try and see how gets on though now has been shaved and cleaned up etc. There is a veterinary nurse who comes and walks the dog a couple of times a week for the owner, however I'm not sure the veterinary nurse's employer will be thrilled about that arrangement continuing, let alone her applying topicals to the MRSP area daily, but it is a consideration.

Regarding systemic antimicrobials if go down that route:

I was surprised how expensive chloramphenicol 250mg tablets were at the first supplier I checked @ over £400 for 30!!! I remember in my first job the boss used to use them and they couldn't have been more than 10p a tablet!

The US dog-licensed ones (Viceton) look cheap enough in USA and come in larger sizes, but for me to import may be expensive or hard to actually import... https://www.bimedaus.com/PDF-Flip/index.html

BOVA do an oily paste aimed at horses that could be used relatively economically, but I am a bit reluctant for owner to be drawing this up from a tub.

I'm not sure if there is another formulation / option / source of affordable chloramphenicol about. It is apparently very chemically-stable, so perhaps I should ask my first boss if still has a tub left (only joking, for clarity).

I hadn't looked at minocycline as thought didn't bode well that was doxycycline resistant, but it does look to be readily available and affordable, so I'll look into that also.

If could use florfenicol that would be great! I loved it for cattle and again had a boss who was known to jag it to dogs at one point, but I thought the half-life was too short in dogs to likely be useful as an injectable, but I see oral suspensions aimed at dogs are available from US compounders at any rate, so perhaps if can be used orally that might be a consideration - there seem to be quite a lot of oral preparations for pigs readily available, as well as the injectable cattle Nuflor-ones I'm more familiar with.

Re rifampicin / mupiricin: the footnote to the bracketed (3) after them advises should be reserved for human use. I don't want to name the lab without their permission, but it is my preferred lab for cultures.

RE: How do you deal with MRSP? Any experience with chloramphenicol?

Stephen Shaw — Mon, 05 Jun 2023 16:03:50 GMT

Some thoughts. There is not enough information for a specific answer.

Tail pyoderma is relatively uncommon, even in atopic dogs. Do you have a feel for the cause? Has this been fully investigated (e.g. atopic dermatitis, endocrine disease etc)?

I would definitely add pain relief to try to increase compliance as well as for welfare.

Consider using minocycline as an alternative to chloramphenicol (which can be difficult to get and expensive, although some report cheaper prices). You need to be treating the areas topically. Use chlorhexidine shampoo / foam / spray to provide some antimicrobial action, perhaps combining this with hypochlorous and/or flamazine which might be better tolerated. Injectable systemic florfenicol has been reported to be useful in small animals although I have no experience. Traditionally rifampicin is usually used as a 'second' antibiotic due to development of resistance, but is reported for sole use in MRSP but can be hepatotoxic.

If the dog cannot be washed / bathed / treated topically in the long term, then any treatment success now, without either addressing the underlying cause more completely, will likely be rather temporary.

What lab is reporting mupirocin? - surely that should be reserved for people. It is an important antibiotic. Is there a dire warning at the bottom of the page?

Bajwa, J., et al. (2013). "Adverse effects of rifampicin in dogs and serum alanine aminotransferase monitoring recommendations based on a retrospective study of 344 dogs." Vet Dermatol 24(6): 570-575, e135-576.
De Lucia, M., et al. (2017). "Rifampicin treatment of canine pyoderma due to multidrug-resistant meticillin-resistant staphylococci: a retrospective study of 32 cases." Vet Dermatol 28(2): 171-e136.
Hicks, K., et al. (2021). "Genomic and in vitro pharmacodynamic analysis of rifampicin resistance in multidrug-resistant canine Staphylococcus pseudintermedius isolates." Vet Dermatol 32(3): 219-e267.
Maaland, M. G., et al. (2014). "Minocycline pharmacokinetics and pharmacodynamics in dogs: dosage recommendations for treatment of meticillin-resistant Staphylococcus pseudintermedius infections." Vet Dermatol 25(3): 182-190, e146-187.