Study urges vets to be wary of yeast overgrowth in canine ear treatment

Vets have been warned to be vigilant against the risk of yeast overgrowth in dogs’ ears following antibacterial treatment based on the findings of a new study.

RVC researchers say they are now aiming to find new ways of limiting the build-up without undermining the effectiveness of treatments against bacterial otitis externa.

The commitment follows the release of research, funded by BSAVA PetSavers, which recorded higher yeast populations after two different treatments were used.

Dogs treated

A total of 29 dogs were treated with either fluoroquinolone (FQ) or piperacillin-tazobactam (PT), both of which the study said substantially reduced bacterial levels.

But while yeasts were isolated in only 6 of 45 ears treated prior to the drugs being administered, that number jumped to 29 afterwards.

All but one of the yeasts were Malassezia pachydermatis, with the other being Candida dubliniensis, with all PT-treated dogs having yeasts isolated from them post-treatment, the paper published in the Journal of Small Animal Practice argued.

Reports

The researchers said they had observed the overgrowth was “not an infrequent sequel” to successful treatment, though they were not aware of other similar canine reports, and “sporadic” cases had also been observed in humans.

Corresponding author Ross Bond said: “We are very grateful to BSAVA PetSavers for kindly funding this study and to the owners of the dogs for agreeing to participate.

“It was most gratifying to be able to confirm our previous observations by use of semi-quantitative cultures.

“Our next goal is to find treatment protocols that prevent the fungal dysbiosis without compromising the efficacy of the antibacterial therapy in these very difficult ear cases.”