Campylobacter cross-contamination of chicken products at an abattoir.

Consumption of raw or undercooked poultry products contaminated with Campylobacter has been identified as a risk factor for human campylobacteriosis. We determined whether slaughtering of Campylobacter-positive flocks was associated with contamination of chicken products derived from Campylobacter-negative flocks slaughtered at the same abattoir. The presence of Campylobacter was investigated in 22 broiler farms 1 week prior to slaughter and in one abattoir on nine separate slaughter days. A total of 600 bulk packed chicken products were tested, with 198 (33.0%) of the products found to be Campylobacter positive. Of the 350 chicken products originating from Campylobacter-positive flocks, 180 (51.1%) were contaminated with the bacteria. In contrast, only 18 (7.2%) of 250 chicken products derived from Campylobacter-negative flocks were contaminated. In 14 of these 18 products, the Campylobacter isolates were identical to isolates obtained from the flock slaughtered immediately prior to the Campylobacter-negative flock. Notably, on 4/6 slaughter days, Campylobacter-negative flocks were slaughtered prior to the positive flocks, and Campylobacter was absent from all chicken products originating from the negative flocks. These results suggest that implementation of logistic slaughter (where Campylobacter-negative flocks are slaughter first) significantly decreases the prevalence of Campylobacter-positive chicken products.

Prevalence and antimicrobial susceptibility of Salmonella in Japanese broiler flocks.

This study determined the prevalence and antimicrobial susceptibility of Salmonella isolated from broiler flocks in Japan. Caecal dropping samples were collected from 288 broiler flocks between November 2007 and February 2010. Salmonella was prevalent in 248 (86·1%) broiler flocks. The top three serovars were S. Infantis, S. Manhattan and S. Schwarzengrund. S. Infantis was found in all regions tested in this study. However, S. Manhattan and S. Schwarzengrund were frequently found only in the western part of Japan. High antimicrobial resistance rates were observed against oxytetracycline (90·2%), dihydrostreptomycin (86·7%) and ampicillin (36·5%), and 258 (90·5%) of 285 isolates were resistant to two or more antimicrobial agents. Interestingly, 26·3% of isolates were resistant to ceftiofur, especially 38·1% of S. Infantis isolates, although its use in broilers has not been approved in Japan. This study showed that Salmonella is highly prevalent (86·1%) in Japanese broiler flocks, that 90·5% of Salmonella isolates were multidrug-resistant, and that S. Infantis frequently exhibited resistance to cephalosporin antimicrobial agents.

Risk factors for Salmonella prevalence in laying-hen farms in Japan.

Human salmonellosis cases, particularly those caused by Salmonella Enteritidis, have been closely linked to egg consumption. This epidemiological survey was conducted to determine the baseline Salmonella prevalence and identify the risk factors for Salmonella prevalence in laying-hen farms in Japan. Caecal excrement samples and dust samples were obtained from 400 flocks in 338 laying-hen farms. Salmonella was identified in 20.7% of the farms and 19.5% of the flocks. The prevalence of Salmonella was significantly higher in flocks reared in windowless houses than in those reared in open houses. In addition, the risk of Salmonella presence was significantly higher when the windowless house farms implemented induced moulting or in-line egg processing. Efforts to reduce human salmonellosis in Japan should continue to focus on the establishment of control measures in laying-hen farms, especially those with windowless houses implementing induced moulting and equipped with in-line egg processing.

Prevalence and antimicrobial susceptibility of Campylobacter in broiler flocks in Japan.

Campylobacter was isolated from 67 (47.2%) of 142 broiler flocks between September 2009 and February 2010. The prevalence of Campylobacter in broiler flocks was significantly lower during January and February than it was from September to December. Campylobacter colonization was more common in flocks that were not provided with a disinfected water supply, which was consistent with the findings of a previous study. The prevalence of antimicrobial drug-resistant Campylobacter spp. was investigated, and the minimum inhibitory concentrations of eight antimicrobial agents were determined for 122 Campylobacter jejuni isolates and 46 Campylobacter coli isolates from broiler flocks between 2007 and 2010. In this study, 29.5% (36/122) of C. jejuni isolates and 41.3% (19/46) of C. coli isolates were resistant to enrofloxacin (ERFX), whereas all isolates were susceptible to erythromycin. Furthermore, the ERFX-resistant isolates were tested for susceptibility to other classes of antimicrobial agents, and 55.6% (20/36) of ERFX-resistant C. jejuni isolates and 47.4% (9/19) of ERFX-resistant C. coli isolates were resistant to at least one of aminobenzyl penicillin, dihydrostreptomycin and oxytetracycline. To avoid an impact of antimicrobial drug-resistant Campylobacter spp. on the efficacy of antimicrobial treatment for human campylobacteriosis, prudent use of antimicrobial agents is a requisite. The use of antimicrobial agents should be accompanied by various approaches such as prevention of Campylobacter colonization in broiler flocks with the aim of lowering the occurrence of Campylobacter infection in humans.

Prevalence and characterization of Shiga toxin-producing Escherichia coli O157 and O26 in beef farms.

Rectal content grab samples were collected from 2436 beef cattle reared on 406 beef farms in Japan between November 2007 and March 2008. STEC strains O157 and O26 were isolated from 110 (27.1%) and 7 (1.7%) farms, respectively. Farms that tested positive for STEC O157 were located in 35 out of all 47 Japanese prefectures. This indicates that STEC O157 strains are widespread on beef farms nationwide. Of the 2436 tested beef cattle, 218 (8.9%) and 10 (0.4%) had STEC strains O157 and O26 in the rectal content, respectively. The most common Shiga toxin genes detected in the isolated STEC O157 strains were: stx(2c) alone (32.1%), stx(2)/stx(2c) (27.2%), and stx(1)/stx(2) (21.8%). Almost all of the STEC O157 and STEC O26 strains expressed Shiga toxins (Stx). Most of the STEC O157 and STEC O26 strains possessed eaeA and EHEC-hlyA. These results strongly suggest that STEC strains O157 and O26 from beef cattle would be pathogenic to humans. Therefore, it is important to reduce STEC strains O157 and O26 in beef cattle in order to prevent foodborne disease caused by STEC. The presence of dogs and/or cats on a farm was significantly (P=0.02) associated with the prevalence of STEC O157. More research is needed to clarify the role of dogs and cats.