Antimicrobial resistance patterns of Salmonella typhimurium and Salmonella dublin isolated from cattle in Japan

Role of antimicrobial selective pressure and secondary factors on antimicrobial resistance prevalence in Escherichia coli from food-producing animals in Japan

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 resistant Escherichia coli were 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-resistant E. coli under the selective pressure from antimicrobial usage. This paper reviews the trends in antimicrobial resistance in E. coli and 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.

Prevalence of antimicrobial resistance among serotypes of Campylobacter jejuni isolates from cattle and poultry in Japan

Penner serotypes of C. jejuni in a total of 601 isolates from apparently healthy cattle, layer and broiler chickens in Japan were examined between 2001 and 2006. Predominant serotypes were B (O: 2, 19.1%), D (O: 4, 13.5%), Y (O: 37, 7.3%) and G (O: 8, 5.8%), whereas the remaining serotypes made up less than 5% of the total isolates. The frequency of ampicillin resistance in serotype G (65.6%) was significantly higher than in serotypes D (12.5%), B (11.2%), and Y (0%). Our results suggest that serotype is one factor contributing to the prevalence of ampicillin resistance in C. jejuni isolates.