PULSED ACTIVE SURVEILLANCE FOR THE EVALUATION OF COMMENSAL ANTIMICROBIC RESISTANT BACTERIA IN A SMALL ANIMAL VETERINARY UNIVERSITY HOSPITAL: PRELIMINARY RESULTS

Emergence of multidrug-resistant (MDR) bacteria is a massive threat to both human and animal health. Veterinary University Hospitals (VUHs) are considered high-risk environments for the selection and transmission of MDR agents (1) due to the high-density of referred patients and the presence of students. Some of the most frequently isolated MDR bacteria in veterinary medicine are extended-spectrum betalactamase (ESBL) and carbapenemase (CPE)-producing Enterobacteriaceae and methicillin-resistant Staphylococci (MRS). Those MDR bacteria are frequently involved in healthcare-associated infections (HAIs) and outbreaks (2). Like in human settings, a microbiological surveillance system is an important tool to estimate MDR bacteria rates, as well as to prevent HAIs and to serve as a database for infection control. Since November 2020, a surveillance plan has started at the Small Animal Clinic of the Bologna VUH. This plan includes a pulsed active surveillance with periodic sessions of one month, performed every four-months, that aimed at monitoring asymptomatic MDR bacteria carriers rate at the time of hospital admission and at discharge, MDR bacteria-associated risk factors, the % of MDR bacteria acquisition and its trend over time. For every session, 25 patients, hospitalized for at least 48 hours, were sampled at the time of hospital admission and before discharge. Rectal and oral swabs were respectively cultured into selective media for ESBL and CPE-producing Enterobacteriaceae, and for MRS. Owners of included pets were asked to fill a consent form, as well as to fill a survey to investigate potential risk factors for MDR exposure (e.g., comorbidities, previous antimicrobial treatments, ...). Preliminary results obtained from 3 sessions of pulsed active surveillance and a total of 75 investigated patients indicated a % of MDR bacteria carriage of 45,3% (95% CI, 34- 56,6) at the admission and of 65,3% (95% CI, 54,5-76,1) at discharge, with a % of MDR acquisition of 38,3% (95% CI, 27,3-49,3). Risk factors for acquisition were >6 days of hospitalization (p=0.017844) and antimicrobial treatment during hospital stay (p=0.01357). ESBL-producing Escherichia coli was the most frequently isolated species. Those preliminary results need to be extended in terms of number of patients and further analyzed by genotypic and phenotypic characterizations of isolates to better define resistance patterns and perform an epidemiologic evaluation.