Minimum inhibitory concentrations of equine Corynebacterium pseudotuberculosis isolates (1996-2012)
D M Rhodes1, K G Magdesian, B A Byrne
1School of Veterinary Medicine, W.R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA.
Journal of Veterinary Internal Medicine
|January 15, 2015
Summary
Minimum inhibitory concentrations for antimicrobials against equine Corynebacterium pseudotuberculosis remained stable from 1996 to 2012. Abscess location did not influence antimicrobial susceptibility patterns in these equine isolates.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Resistance
- Equine Infectious Diseases
Background:
- Limited data exists on antimicrobial minimum inhibitory concentrations (MICs) for equine Corynebacterium pseudotuberculosis.
- Equine Corynebacterium pseudotuberculosis causes significant disease, necessitating effective antimicrobial treatment.
Purpose of the Study:
- To assess trends in in vitro antimicrobial activity against equine Corynebacterium pseudotuberculosis isolates.
- To evaluate antimicrobial susceptibility over time (1996-2012).
- To determine any correlation between MICs and abscess location.
Main Methods:
- A retrospective and cross-sectional study analyzed 196 equine Corynebacterium pseudotuberculosis isolates.
- Minimum inhibitory concentrations (MICs) were determined using microdilution.
- Isolates were grouped into three time periods: 1996-2001, 2002-2006, and 2007-2012.
Main Results:
- MIC90 values for key antimicrobials like chloramphenicol, enrofloxacin, gentamicin, penicillin, rifampin, tetracycline, trimethoprim-sulfamethoxazole (TMS), ceftiofur, and doxycycline were determined.
- No significant temporal changes in MIC results were observed across the study periods.
- No association was found between MIC patterns and the location of the abscess.
Conclusions:
- Antimicrobial MICs for equine Corynebacterium pseudotuberculosis isolates showed no significant variation over the 17-year study period.
- Abscess location did not correlate with differing MIC patterns.
- Commonly used antimicrobials demonstrated consistent in vitro activity against the evaluated isolates.
