Effect of media, temperature and culture conditions on the species population and antibiotic resistance of enterococci from broiler chickens.

AIMS The effect of media type, incubation temperature and enrichment period on the species population and antibiotic susceptibility of enterococci from poultry carcass rinsates was determined. METHODS AND RESULTS Aliquots of rinsates, incubated in BBL Enterococcosel broth at 37 degrees C, 42 degrees C, or 45 degrees C for 24 and 48 h, were inoculated onto BBL Enterococcosel and M-enterococcus agar. Presumptive positive colonies were identified to species and tested for antibiotic resistance. Significant differences (P < or = 0.05) were observed for media and temperature. More Enterococcus faecalis were isolated from M-enterococcus media and at 37 degrees C while more E. faecium were isolated from Enterococcosel agar and at 45 degrees C. The number of antibiotic-resistant E. faecalis and E. faecium were also affected by media and temperature. CONCLUSIONS Culture conditions for enterococci affect the observed species and antibiotic resistance patterns and therefore should be carefully considered. SIGNIFICANCE AND IMPACT OF THE STUDY This study indicates that media and temperature can influence the recovery and selection of enterococcal species and antibiotic susceptibility.