Usage patterns of carbapenem antimicrobials in dogs and cats at a veterinary tertiary care hospital.

BACKGROUND: Carbapenems are a class of antimicrobials reserved for resistant infections or systemically ill people, yet the extent and context in which they are prescribed in the small animals is understudied. HYPOTHESIS/OBJECTIVE: To describe cases in dogs and cats treated with carbapenems to establish baseline data regarding the types of infections, outcomes, and resistance profiles of target infections. We hypothesize that prescribing practices for carbapenems at a veterinary tertiary care hospital would not comply with the recommended use guidelines in human medicine. METHODS: Retrospective study of veterinary medical records from all dogs and cats prescribed carbapenems between May 1, 2016, and April 30, 2017. RESULTS: A total of 81 infections (71 in dogs and 10 in cats) representing 68 animals (58 dogs and 10 cats) involving carbapenem use were identified. Cultures were performed in 65/81 (80%) infections, and antimicrobial use was de-escalated or discontinued in 10/81 (12%) infections. The average duration of treatment was 27.5 days and ranged from 1 to 196 days. Resistance to more than 3 antimicrobial classes was present in 57/115 (50%) isolates. Resistance to carbapenems was found in 2/64 (3%) of the bacterial isolates with reported carbapenem susceptibility. CONCLUSIONS AND CLINICAL IMPORTANCE: The majority of carbapenem use at a veterinary tertiary care hospital was prescribed in conjunction with culture and sensitivity determination, with de-escalation performed in a minority of cases, and treatment durations longer than typically recommended in human medicine.

Patterns and predictors of antimicrobial resistance among Staphylococcus spp. from canine clinical cases presented at a veterinary academic hospital in South Africa.

BACKGROUND: Antimicrobial resistance in staphylococci, often associated with treatment failure, is increasingly reported in veterinary medicine. The aim of this study was to investigate patterns and predictors of antimicrobial resistance among Staphylococcus spp. isolates from canine samples submitted to the bacteriology laboratory at the University of Pretoria academic veterinary hospital between 2007 and 2012. Retrospective data of 334 Staphylococcus isolates were used to calculate the proportion of samples resistant to 15 antimicrobial agents. The Cochran-Armitage trend test was used to investigate temporal trends and logistic regression models were used to investigate predictors of antimicrobial resistance in Staphylococcus aureus and Staphylococcus pseudintermedius. RESULTS: Results show that 98.2% (55/56) of the S. aureus isolates were resistant to at least one drug while 42.9% were multidrug resistant. Seventy-seven percent (214/278) of the S. pseudintermedius isolates were resistant to at least one drug and 25.9% (72/278) were multidrug resistant. Resistance to lincospectin was more common among S. aureus (64.3%) than S. pseudintermedius (38.9%). Similarly, resistance to clindamycin was higher in S. aureus (51.8%) than S. pseudintermedius (31.7%) isolates. There was a significant (p = 0.005) increase in S. aureus resistance to enrofloxacin over the study period. Similarly, S. pseudintermedius exhibited significant increasing temporal trend in resistance to trimethoprim-sulphamethoxazole (p = 0.004), clindamycin (p = 0.022) and orbifloxacin (p = 0.042). However, there was a significant decreasing temporal trend in the proportion of isolates resistant to doxycycline (p = 0.041), tylosin (p = 0.008), kanamycin (p = 0.017) and amoxicillin/clavulanic acid (p = 0.032). CONCLUSIONS: High levels of multidrug resistance and the increasing levels of resistance to sulphonamides, lincosamides and fluoroquinolones among Staphylococcus spp. isolates in this study are concerning. Future studies will need to investigate local drivers of antimicrobial resistance to better guide control efforts to address the problem.

Hyperascorbaemia in dogs admitted to a teaching hospital intensive care unit.

OBJECTIVE: To determine whether or not dogs develop a deficiency of ascorbic acid during hospitalisation in an intensive care unit. METHODS: Blood samples were collected daily for up to three days from dogs hospitalised in an intensive care unit for 36 to 72 hours (n = 16) or ê72 hours (n = 20) and from healthy dogs (n = 13). Plasma total ascorbic acid concentrations were measured using a colorimetric method involving a reaction between ascorbic acid, 2,6 dichlorophenol-indophenol, thiourea and dinitrophenyl hydrazine. Additionally, clinical data were recorded for each patient. RESULTS: Dogs hospitalised for ê72 hours had significantly greater plasma ascorbic acid concentrations on day 3 compared to days 1 and 2. There was no difference in plasma ascorbic acid concentrations between days 1 and 2 for dogs hospitalised for 36 to 72 hours. Plasma ascorbic acid concentrations were significantly greater for each day of sampling for the hospitalised dogs compared to the control dogs. CLINICAL SIGNIFICANCE: Plasma ascorbic acid concentrations appear to increase during hospitalisation, and supplementation may not be indicated in dogs hospitalised in an intensive care unit.