Cumulative antibiogram and multidrug-resistant organisms in a regional equine referral hospital

Antimicrobial susceptibility patterns of aerobic bacteria isolated from canine urinary samples in South East Queensland, 2013 to 2018

Urinary tract infections are a common diagnosis in dogs presenting to veterinary practice. Veterinarians often treat suspected infections empirically, either in the absence of culture and susceptibility testing results or whilst waiting for them. This study aimed to identify the bacteria most frequently isolated from canine urinary samples and their antimicrobial susceptibility patterns in South East Queensland (SEQ) to help guide responsible empirical antimicrobial prescription by the veterinary community in this geographical location. Cumulative antibiograms were generated from the results of 1284 culture-positive urinary samples in SEQ, obtained from a commercial veterinary laboratory over a 5-year period. Escherichia coli was the most commonly isolated bacterial species (43%), followed by Staphylococcus spp. (23%), Proteus spp. (21%) and Enterococcus spp. (10%). Of the six most common isolates, 97% had susceptibility to at least one low-importance antimicrobial. Susceptibility to the low-importance and first-line antimicrobial recommendation, amoxicillin, was 81% for E. coli and 24% for Staphylococcus spp. Susceptibility of both E. coli and Staphylococcus spp. to medium-importance and commonly recommended empirical antimicrobials, trimethoprim sulphonamides and amoxicillin-clavulanic acid was ≥85% and >92% for high-importance antimicrobials enrofloxacin and ceftiofur. Of the E. coli and Staphylococcus spp. isolates, 8.8% and 4%, respectively, were considered multidrug resistant. There was no increase in resistance to antimicrobials detected over the study period. Susceptibilities suggest low- and medium-importance antimicrobials remain acceptable first-line empirical treatments. However, this should be continually assessed and updated using local surveillance data.

Right dorsal colitis in horses: A multicenter retrospective study of 35 cases

BACKGROUND

Right dorsal colitis (RDC) is a nonsteroidal anti-inflammatory drug (NSAID) induced, protein losing enteropathy in horses associated with a high case fatality rate.

OBJECTIVES

To describe signalment, NSAID usage, clinical presentations, clinical pathology, ultrasonographic findings, treatments, outcomes, and factors associated with survival in horses diagnosed with RDC.

ANIMALS

Thirty-five horses from 7 Australian equine hospitals diagnosed with RDC.

METHODS

Retrospective case series. Clinical records of cases were accepted if definitively or presumptively diagnosed by an internist with RDC and had ≥3 of: hypoproteinemia or hypoalbuminemia; diarrhea with negative test results for infectious diseases; colic for which other diseases were excluded or right dorsal colon thickening on ultrasound. Descriptive data analysis was performed for categorical and continuous variables. Univariate binominal logistic regressions were used to assess factors associated with survival.

RESULTS

An overdose of NSAIDs occurred in 84% (21/25) cases where dose was known. Common clinical presentations included diarrhea (69%; 22/32), colic (61%; 20/33), and tachycardia (53%, 17/32). Common clinicopathological findings included hypoalbuminemia (83%; 26/31), hypocalcaemia (79%, 23/29), and hyperlactatemia (77%, 14/18). The right dorsal colon wall appeared subjectively thickened in 77% (24/31) cases using ultrasonography. Case fatality rate was 43% (15/35). Odds of survival significantly decreased with increasing heart rate (odds 0.84, 95% CI = 0.71-0.92, P = .01), packed cell volume (odds 0.91, 95% CI 0.82-0.98, P = .05) and abnormal appearance of mucous membranes (odds 0.05, 95% CI 0.005-0.28, P = .001) on hospital presentation.

CONCLUSIONS AND CLINICAL IMPORTANCE

An overdose of NSAIDs is common in horses diagnosed with RDC. Serum albumin concentrations should be monitored in horses receiving a prolonged course of NSAIDs. Overall prognosis for RDC remains fair.

A VetCompass Australia Study of Antimicrobial Use in Dog-to-Dog Bite Wounds (1998-2018)

Although dog-to-dog bite wounds (DBW) are a common presentation to veterinary clinics, antimicrobial prescribing habits of Australian clinics have not been reported. This study determined the frequency and results of DBW cultures; antimicrobial selection; and importance class of antimicrobials prescribed relative to wound severity, geographic location, or year. A systematic sample of 72,507 patient records was retrieved from the VetCompass Australia database. Records for 1713 dog bite events involving 1655 dogs were reviewed for presenting signs, results of culture and susceptibility testing (C&S), antimicrobial treatment, geographical location, and outcome. A crossed random effects multivariable logistic regression model was used to determine if antimicrobial importance was associated with wound severity, year, and location, and to assess the differences in antimicrobial prescription between geographical locations, clinics, and veterinarians. Antimicrobials were prescribed in 86.1% of DBW. Amoxicillin-clavulanic acid was prescribed in 70% (1202/1713) with underdosing in 15.8% (191/1202). High-importance antimicrobial use was associated with wound severity (p < 0.001), year category (p = 0.007), and surgery (p = 0.03). C&S testing was recorded as having been performed in only one case. Differences in individual veterinarian prescribing habits were stronger than the clinic culture, suggesting that education utilizing clinic-wide antimicrobial guidelines may aid in improving antimicrobial stewardship.