Acquisition and carriage of multidrug-resistant organisms in dogs and cats presented to small animal practices and clinics in Switzerland.

Background: The emergence and spread of multidrug-resistant organisms (MDRO) present a threat to human and animal health.

Objectives: To assess acquisition, prevalence of and risk factors for MDRO carriage in dogs and cats presented to veterinary clinics or practices in Switzerland.

Animals: Privately owned dogs (n = 183) and cats (n = 88) presented to 4 veterinary hospitals and 1 practice.

Methods: Prospective, longitudinal, observational study. Oronasal and rectal swabs were collected at presentation and 69% of animals were sampled again at discharge. Methicillin-resistant (MR) staphylococci and macrococci, cephalosporinase-, and carbapenemase-producing (CP) Enterobacterales were isolated. Genetic relatedness of isolates was assessed by repetitive sequence-based polymerase chain reaction and multilocus sequence typing. Risk factors for MDRO acquisition and carriage were analyzed based on questionnaire-derived and hospitalization data.

Results: Admission prevalence of MDRO carriage in pets was 15.5% (95% confidence interval [CI], 11.4-20.4). The discharge prevalence and acquisition rates were 32.1% (95% CI, 25.5-39.3) and 28.3% (95% CI, 22-35.4), respectively. Predominant hospital-acquired isolates were extended spectrum β-lactamase-producing Escherichia coli (ESBL-E coli; 17.3%) and β-lactamase-producing Klebsiella pneumoniae (13.7%). At 1 institution, a cluster of 24 highly genetically related CP (bla and bla ) was identified. Multivariate analysis identified hospitalization at clinic 1 (odds ratio [OR], 5.1; 95% CI, 1.6-16.8) and days of hospitalization (OR 3-5 days, 4.4; 95% CI, 1.8-10.9; OR > 5 days, 6.2; 95% CI, 1.3-28.8) as risk factors for MDRO acquisition in dogs.

Conclusions: Veterinary hospitals play an important role in the selection and transmission of MDRO among veterinary patients.