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To determine the prevalence and antimicrobial susceptibility profiles of Campylobacter, Salmonella, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and vancomycin-resistant enterococci (VRE) in food-producing animals and retail raw meats in Japan, raw meat samples as well as food-producing animal feces, cutaneous swabs, and nasal swabs collected from 2004 to 2006 were analyzed. Isolation rates of Campylobacter jejuni and Campylobacter coli, Salmonella, and S. aureus were 34.6% (363 of 1,050), 2.7% (28 of 1,050), and 32.8% (238 of 725), respectively. MRSA was isolated from 3% (9 of 300) of meat samples. No VRE were isolated in this study. Antibiotic resistance in C. coli was higher than that in C. jejuni. Three C. jejuni isolates from a patient with diarrhea in a hospital of Shizuoka Prefecture and two chicken samples that exhibited resistance to ciprofloxacin had identical pulsed-field gel electrophoresis patterns, suggesting that ciprofloxacin-resistant C. jejuni could have been distributed in meat. S. aureus isolates showed the highest level of resistance to ampicillin and tetracycline. Resistance to tetracycline in S. aureus isolates from beef was lower than that seen in isolates from chicken and pork (P < 0.01). This study revealed that the prevalence of MRSA and VRE were low in food-producing animals and retail domestic meats in Japan, although Campylobacter isolates resistant to fluoroquinolone and erythromycin were detected. The occurrence of antimicrobial-resistant pathogens should be monitored continuously to improve the management of the risks associated with antimicrobial drug resistance transferred from food-producing animals to humans.

ABSTRACT. The incidence and numbers of enterotoxigenic Clostridium perfringens in the intestinal contents of cattle, swine and broiler chickens were determined and compared with those of total (enterotoxigenic and nonenterotoxigenic) C. perfringens. The method used for the enumeration of enterotoxigenic C. perfringens consisted of a combination of the most probable number (MPN) method and a nested polymerase chain reaction after enrichment culture of the sample. Enterotoxigenic C. perfringens was found in 26% (4.0 × 10-4.3 × 10 2 MPN/100 g), 22% (4.0 × 10-2.3 × 10 3 MPN/100 g) and 40% (4.0 × 10-2.4 × 10 4 MPN/100 g) of intestinal contents of 50 head each of cattle, swine and broiler chickens, respectively. Whereas, total C. perfringens was found in 76% (9.0 × 10-7.5 × 10 6 MPN/100 g), 44% (7.0 × 10-4.3 × 10 6 MPN/100 g) and 80% (4.3 × 10 2 -9.3 × 10 7 MPN/100 g) of intestinal contents of 50 head each of cattle, swine and broiler chickens, respectively, by the conventional MPN method. In all cases, enterotoxigenic cells were not dominant in the population of C. perfringens: a small number of enterotoxigenic cells of C. perfringens co-existed with a large number of nonenterotoxigenic cells in the same sample. The ratios of enterotoxigenic C. perfringens cells to total C. perfringens cells were 1/10-1/10 5 . -KEY WORDS: Clostridium perfringens, enterotoxin, livestock, MPN, PCR.