Prevalence Of Extended-Spectrum Cephalosporin-, Carbapenem-, And Fluoroquinolone-Resistant Members Of The Family Enterobacteriaceae Isolated From The Feces Of Horses And Hospital Surfaces At Two Equine Specialty Hospitals

OBJECTIVETo estimate the prevalence of extended-spectrum cephalosporin-, carbapenem-, and fluoroquinolone-resistant bacteria of the family Enterobacteriaceae in the feces of hospitalized horses and on hospital surfaces.SAMPLEFecal and environmental samples were collected from The Ohio State University Galbreath Equine Center (OSUGEC) and a private referral equine hospital in Kentucky (KYEH). Feces were sampled within 24 hours after hospital admission and after 48 hours and 3 to 7 days of hospitalization.PROCEDURESFecal and environmental samples were enriched, and then selective media were inoculated to support growth of Enterobacteriaceae bacteria that expressed resistance phenotypes to extended-spectrum cephalosporins, carbapenems, and fluoroquinolones.RESULTS358 fecal samples were obtained from 143 horses. More samples yielded growth of Enterobacteriaceae bacteria that expressed resistance phenotypes (AmpC beta-lactamase, OR = 4.2; extended-spectrum beta-lactamase, OR = 3.2; and fluoroquinolone resistance, OR = 4.0) after 48 hours of hospitalization, versus within 24 hours of hospital admission. Horses hospitalized at KYEH were at greater odds of having fluoroquinolone-resistant bacteria (OR = 2.2). At OSUGEC, 82%, 64%, 0%, and 55% of 164 surfaces had Enterobacteriaceae bacteria with AmpC beta-lactamase phenotype, extended-spectrum beta-lactamase phenotype, resistance to carbapenem, and resistance to fluoroquinolones, respectively; prevalences at KYEH were similarly distributed (52%, 32%, 1%, and 35% of 315 surfaces).CONCLUSIONS AND CLINICAL RELEVANCEResults indicated that antimicrobial-resistant Enterobacteriaceae may be isolated from the feces of hospitalized horses and from the hospital environment. Hospitalization may lead to increased fecal carriage of clinically important antimicrobial-resistance genes.