A nationwide surveillance for antimicrobial susceptibility in Escherichia coli strains isolated from food-producing animals in Japan was conducted from 1999 to 2002. Eighteen cefazolin-resistant E. coli strains were isolated from broilers. Six were CTX-M-type producing, and eight were CMY-2 producing, while eight had mutations at the ampC promoter region.

The use of antimicrobial agents in the veterinary field affects the emergence, prevalence, and dissemination of antimicrobial resistance in bacteria isolated from food-producing animals. To control the emergence, prevalence, and dissemination of antimicrobial resistance, it is necessary to implement appropriate actions based on scientific evidence. In Japan, the Japanese Veterinary Antimicrobial Resistance Monitoring System (JVARM) was established in 1999 to monitor the antimicrobial susceptibility of foodborne and commensal bacteria from food-producing animals. The JVARM showed that the emergence and prevalence of resistantEscherichia coliwere likely linked to the therapeutic antimicrobial use in food-producing animals through not only direct selection of the corresponding resistance but also indirect selections via cross-resistance and coresistance. In addition, relevant factors such as host animals and bacterial properties might affect the occurrence and prevalence of antimicrobial-resistantE. coliunder the selective pressure from antimicrobial usage. This paper reviews the trends in antimicrobial resistance inE. coliand consumption of antimicrobials agents in Japan and introduces the relationship between antimicrobial usage and prevalence of antimicrobial-resistant bacteria, from food-producing animals under the JVARM program. In this paper, we will provide the underlying information about the significant factors that can help control antimicrobial resistance in bacteria in veterinary medicine.

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We compared the overall usage of veterinary therapeutic antimicrobials in Japan to the proportion of antimicrobial-resistant. Escherichia coli isolated from the feces of apparently healthy food-producing animals in 2001. The annual sales volume of veterinary antimicrobials, which is published and accumulated information, was subdivided according to the target animal species (cattle, pigs, broiler chickens, and layer chickens). The antimicrobial susceptibility of the isolates was examined against 7 classes of 11 antimicrobials. The rates of antimicrobial resistance among the isolates were found to correlate significantly with the usage of antimicrobial agents in cattle, pigs, and broiler and layer chickens. Therefore, the overall usage of veterinary antimicrobials appears to contribute to the appearance of antimicrobial resistance in E. coli isolates from apparently healthy food-producing animals.