Longitudinal evaluation of the cutaneous and rectal microbiota of German shepherd dogs with perianal fistulas undergoing therapy with ciclosporin and ketoconazole

BACKGROUND

Perianal fistulas are painful ulcers or sinus tracts that disproportionately affect German shepherd dogs and are proposed as a spontaneous animal model of fistulising Crohn's disease.

OBJECTIVES

To characterise the rectal and cutaneous microbiota in German shepherd dogs with perianal fistulas and to investigate longitudinal shifts with lesion resolution during immunomodulatory therapy.

ANIMALS

Eleven German shepherd dogs with perianal fistulas and 15 healthy German shepherd dogs.

MATERIALS AND METHODS

Affected dogs were evaluated and swabbed at three visits, 30 days apart, while undergoing treatment with ciclosporin and ketoconazole. Healthy German shepherd dogs were contemporaneously sampled. Sites included the rectum, perianal skin and axilla. The microbiome was evaluated following sequencing of the V4 hypervariable region of the 16S ribosomal RNA (rRNA) gene.

RESULTS

Alpha diversity was not significantly different between healthy and affected dogs at each of the three body sites (p > 0.5), yet rectal and perianal beta diversities from affected dogs differed significantly from those of healthy dogs at Day 0 (p = 0.004). Rectal and perianal relative abundance of Prevotella spp. increased and perianal Staphylococcus spp. relative abundance decreased in affected dogs over time, coincident with lesion resolution.

CONCLUSIONS AND CLINICAL RELEVANCE

Changes in lesional cutaneous and rectal microbiota occur in German shepherd dogs with perianal fistulas and shift over time with lesion resolution during immunomodulatory therapy. Further investigations of the role of cutaneous and enteric microbiota in the pathogenesis of perianal fistulas, and whether manipulation of microbial populations may ameliorate disease, are needed.

Genomic and clinical case characterisation of Staphylococcus haemolyticus isolated from dogs and cats in the United States, including strains with high-level mupirocin tolerance

BACKGROUND

Staphylococcus haemolyticus is a coagulase-negative commensal organism of both people and companion animals. It has pathogenic potential and when cultured is often meticillin- and multidrug-resistant.

OBJECTIVES

To characterise the clinical features of dogs and cats with clinical skin disease that had positive S. haemolyticus skin cultures, and to employ whole-genome sequencing (WGS) to identify resistance genes and characterise the genetic relatedness of strains.

MATERIALS AND METHODS

Isolates were identified by the institutional clinical microbiology laboratory by routine aerobic culture and susceptibility from seven veterinary hospitals across the United States. Then, WGS and analysis of each isolate were performed and clinical data collected via a retrospective clinician questionnaire.

RESULTS

S. haemolyticus was identified from superficial (seven of 12) and deep (five of 12) cutaneous infections in our study. Most animals had received antimicrobials (10 of 12) and/or immunomodulatory drugs (nine of 12) within the six months before culture. WGS analysis revealed a variety of genetic lineages and a wide array of antimicrobial resistance genes. Meticillin resistance was identified in nine of 12 isolates and four of 12 isolates demonstrated mupirocin tolerance.

CONCLUSIONS AND CLINICAL RELEVANCE

Staphylococcus haemolyticus may be an under-recognised pathogen in companion animals, and its demonstrated potential for multidrug-resistance, meticillin-resistance, and high-level mupirocin tolerance may create a therapeutic challenge. Further studies should evaluate the prior antimicrobial use and immunocompromised status as risk factors for infection with S. haemolyticus.

Urine cortisol-creatinine and protein-creatinine ratios in urine samples from healthy dogs collected at home and in hospital

Background

Recently, urine protein:creatinine ratios (UPC) were shown to be lower in urine samples from dogs collected at home (AH) as compared to those collected in hospital (IH). Stress‐inducing procedures and travel to the hospital have been hypothesized to cause prerenal proteinuria.

Objectives

Evaluate patient stress using urine cortisol:creatinine ratios (UCCr) and correlate UCCr to UPC in urine samples obtained AH and IH.

Animals

Thirty‐six healthy, client‐owned dogs.

Methods

Prospective, non‐masked study. Two voided urine samples were obtained (AH and IH). Complete urinalysis as well as UPC and UCCr were performed. Clients graded their dogs' stress level AH, in transport, and IH.

Results

The UCCr was significantly higher in IH samples than in AH samples (P < .0001), but UPC was not significantly different between AH and IH urine samples (P = .14). In all samples and in both collection settings, UCCr was not significantly correlated with UPC. Travel time and time IH were not correlated with change in UCCr or UPC. In 8 dogs with borderline or overt proteinuria, no significant difference was found in UPC between settings, but UCCr was significantly higher in IH samples.

Conclusions and Clinical Importance

The UPC was not higher when measured in urine samples collected IH compared to AH. Dogs had higher UCCr IH, but UCCr was not associated with UPC. Stress, as estimated by UCCr, did not affect proteinuria. Further evidence is needed to support the claim that stress may result in proteinuria in healthy dogs.