Identification of macrolide- and rifampicin-resistant Rhodococcus equi in environmental samples from equine breeding farms in central Kentucky during 2018

Publication date: Available online 6 April 2019Source: Veterinary MicrobiologyAuthor(s): L. Huber, S. Giguère, N.D. Cohen, N.M. Slovis, L. Berghaus, M. Greiter, K.A. HartAbstractRhodococcus equi causes severe pneumonia in foals and is most often recognized in people as an opportunistic pathogen. Longitudinal studies examining antimicrobial-resistant R. equi from environmental samples are lacking. We hypothesized that antimicrobial-resistant R. equi would be detectable in the ground (pasture soil or stall bedding) and air at breeding farms with previous documentation of foals infected with resistant isolates, and that concentrations of resistant isolates would increase over time during the foaling season. In this prospective cohort study, ground and air samples were collected from stalls and paddocks in January, March, May and July of 2018 at 10 horse-breeding farms with history of foal pneumonia attributed to macrolide- or Rifampicin-resistant R. equi. Environmental samples were cultured in the presence and absence of macrolides and Rifampicin to select for resistant organisms. Data were analyzed with linear mixed-effects and Hurdle models. Concentrations of total R. equi in bedding or air of stalls were significantly (P < 0.05) higher in January than other months. The proportion of resistant R. equi in soil samples from paddocks was significantly (P < 0.05) higher than stall bedding during all months. For each month, air samples from paddocks had a significa...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research