Feline conjunctival microbiota in a shelter: effects of time, upper respiratory disease and famciclovir administration

Abstract

Objectives The aim of this study was to evaluate changes in the conjunctival microbiota of shelter-housed cats with time, upper respiratory disease (URD) and famciclovir administration. Methods Cats were assigned to treatment groups on shelter entry. Healthy cats or cats with URD received ~30 mg/kg or ~90 mg/kg of famciclovir or placebo PO q12h for 7 days, or were untreated. Swabs were collected from ventral conjunctival fornices prior to (day 1) and immediately after (day 8) the treatment period. Microbiota analysis was conducted on 124 randomly selected swabs from healthy (56 swabs) or URD-affected (68 swabs) cats. Following DNA extraction and amplification of the V4 region of the 16S rRNA gene, sequences were assembled into operational taxonomic units (OTUs). Over-represented OTUs (as determined by linear discriminate analysis effect size), alpha and beta diversity, and median relative abundance of known feline ocular surface pathogens were assessed for the entire population and in 10 clinically relevant subpopulations of cats. Results Bacteria from 33 phyla and 70 genera were identified. Considering all cats, median relative abundance of Mycoplasma increased from day 1 to day 8, while Proteobacteria decreased. Community membership and structure (beta diversity) differed between days 1 and 8 for all famciclovir-treated cats (regardless of health status or dose) and healthy or URD-affected cats (regardless of famciclovir dose). Differences in taxonomic diversity within a sample (alpha diversity) between day 1 and day 8 were not detected in any subpopulations. Conclusions and relevance Within 1 week of shelter entry, there were significant changes in community structure and membership of the feline conjunctival microbiota, with a shift towards over-representation of feline ocular surface pathogens. Although famciclovir may impact beta diversity of the feline conjunctival microbiota, absence of change in alpha diversity suggests minimal shift in individual cats.

Longitudinal study of the cutaneous microbiota of healthy horses

“…The V4 region of the 16S rRNA gene was amplified using the modified 515F/806R amplicon primers as described by Walters et al 24 . Per sample, two PCR reactions and purifications were performed as described in Lucyshyn et al 25 . (Appendix ).…”

“…A negative control containing only reagents was performed for every 70 samples extracted to control for contamination from extraction kits. The V4 region of the 16S rRNA gene was amplified using the modified 515F/806R amplicon primers as described by Walters et al 24 Per sample, two PCR reactions and purifications were performed as described in Lucyshyn et al 25 (Appendix S1). Following the second purification, samples were quantified using a NanoDrop spectrophotometer (NanoDrop, Roche; Mississauga, ON, Canada).…”

A review of evidence‐based management of infectious ocular surface disease in shelter‐housed domestic cats

“…Famciclovir, an orally administered prodrug of penciclovir, has been the subject of numerous investigations for the treatment of FHV-1 in cats. 4,5,8,74,78,[101][102][103][104] Several of these studies specifically utilized shelter-housed cats with IOSD 4,5,8,101 or animals in a 'foster' environment (temporary private residence). 102 Studies using experimental animals in a highly controlled laboratory setting have shown that famciclovir is an effective treatment for FHV-1 and that, at appropriate doses, anti-herpetic concentrations of penciclovir are achievable in the tear film.…”

“…102 Finally, although not specifically assessing drug efficacy, a study of shelter-housed cats treated with famciclovir concluded that the use of oral famciclovir given at 90 mg/kg q12h has minimal impact on the individual bacterial feline ocular surface microbiome. 101 When considered together, the existing clinical trials provide minimal evidence of famciclovir efficacy for treatment of feline IOSD in the shelter environment. Therefore, alternative strategies should currently be considered for shelter-housed cats with FHV-1 IOSD.…”

“…Famciclovir, an orally administered prodrug of penciclovir, has been the subject of numerous investigations for the treatment of FHV‐1 in cats 4,5,8,74,78,101–104 . Several of these studies specifically utilized shelter‐housed cats with IOSD 4,5,8,101 or animals in a ‘foster’ environment (temporary private residence) 102 .…”