Abstract
From April 2002 to March 2008, we collected a total of 210 Salmonella enterica serovar Infantis (Salmonella Infantis) isolates from domestic chicken meat sold by retail stores in Yokohama, Japan. We examined the isolates for antimicrobial susceptibilities to 13 antibiotics (ampicillin, cephalothin, cefotaxime, streptomycin, kanamycin, gentamicin, tetracycline, chloramphenicol, sulfisoxazole, sulfamethoxazole-trimethoprim, nalidixic acid, ciprofloxacin, and fosfomycin). One hundred ninety-four isolates (92.4%) were resistant to at least one antibiotics. Among antibiotics tested, resistance rates against sulfisoxazole, streptomycin, and kanamycin were high.
None of the Salmonella Infantis isolates in this study were resistant to ciprofloxacin. Seven isolates were found to be resistant to ampicillin and cephalothin and 4 isolates were resistant to ampicillin, cephalothin and cefotaxime. Of the 11β-lactamase producing isolates, 5 were found to produce extended-spectrum β-lactamase (ESBL). As a result of the bla gene screening, blaTEM-20, blaTEM-52 and blaCTX-M-2 were detected in 1, 3 and 1 ESBL-producing isolate. In the remaining 6 isolates, blaCMY-2 was detected. Six of the 11 isolates were originated from chicken meat products that were shipped from the same corporation in a couple of years.
Salmonella Infantis producing TEM-20 type ESBL was detected for the first time in this study.
