ARS | Publication request: EFFECT OF MEDIA, TEMPERATURE AND CULTURE CONDITIONS ON THE SPECIES POPULATION AND ANTIBIOTIC RESISTANCE OF ENTEROCOCCI FROM BROILER CHICKENS

Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2005
Publication Date: July 9, 2005
Citation: Jackson, C.R., Cray, P.J., Hall, M.C., Hiott, L.M. 2005. Effect of media, temperature and culture conditions on the species population and antibiotic resistance of enterococci from broiler chickens. Letters in Applied Microbiology. 41(3):262-268.

Interpretive Summary: Although much is known about growth conditions of clinical enterococci, little has been done to elucidate how growth conditions affect species and antimicrobial susceptibility of enterococci. In this study, media type, incubation temperature, and enrichment period were varied in order to determine the effect on enterococci from poultry. Media and temperature affected the species of enterococci isolated, while enrichment period had no significant effect. Antimicrobial resistance patterns were also affected by media and temperature. Researchers from all disciplines can use this information when isolating and determining culturing conditions for enterococci from any source. This research is also useful because mistakes in altering outcomes of epidemiological experiments can be avoided.

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