Simple and efficient screening method for the detection of cephalosporin resistant Escherichia coli.

摘要

An efficient method for cephalosporin resistance screening in E. coli isolated from healthy farm animals has been described. One hundred and twenty nine rectal swabs were streaked on MacConkey agar and selective medium supplemented with cefotaxime. Antimicrobial resistance was tested with broth microdilution and E. coli resistant to either/or cefotaxime and ceftazidime were further tested with Etest. The observed synergy of the compounds allowed confirming the presence of defined cephalosporin resistance phenotypes. The sensitivity of cephalosporin detection by the procedure with MacConkey culture reached merely 16.7% compared to the method with selective supplement medium. Extended spectrum of beta-lactamase producing isolates was found in strains isolated from 15 samples taken from turkeys, broilers, laying hens, and pigs. The ampC-type resistance was noted in E. coli from 33 samples originating from the same animal species. None of the resistance phenotypes was observed in cattle isolates. Attention is drawn to possible public health implications of slaughtered farm animals colonised with beta-lactam resistant E. coli.