104th General Meeting of the American Society for Microbiology
May 23-27, 2004, New Orleans, Louisiana
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EMBARGOED UNTIL: Tuesday, May 25, 8:00 a.m. CDT
(Session 118)
Patrick McDermott
Food and Drug Administration
Laurel, MD, United States
Phone: 301-827-8024

The Centers for Disease Control and Prevention (CDC) has estimated that foodborne infections cause approximately 76 million illnesses, 325,000 hospitalizations, and 5000 deaths each year. The annual cost of foodborne illnesses caused by the 2 most common foodborne bacterial pathogens (Salmonella and Campylobacter) has been estimated in the billions of dollars. Monitoring the microbial safety of the nation's food supply, therefore, is a critical public health function. To meet this need, the National Antimicrobial Resistance Monitoring Systems (NARMS) expanded in 2002 to add retail meat surveillance.

As a pilot project to NARMS, A 15-month long study was conducted across the state of Iowa examining samples of chicken breasts, pork chops, ground turkey, and ground beef for the presence of Salmonella and Campylobacter. Over 800 meats samples from 263 grocery stores distributed statewide were examined. During the same time period, isolates from human clinical cases in Iowa were also collected. All bacteria were tested for antibiotic resistance, and compared at the DNA level by genetic fingerprinting (using pulsed-field gel electrophoresis [PFGE]).

For Campylobacter, a total of 192 meats isolates and 185 human isolates were examined. The overall contamination rate for all meats was 21%. The vast majority of Campylobacter were found in chicken breasts (75%), followed by ground turkey (7%) and pork chops (1%); none were detected in ground beef. C. jejuni was the predominant species recovered (59%), followed by C. coli (41%). C. jejuni was the predominant species from chicken (63%), and C. coli predominated in ground turkey (73%). Ciprofloxacin and erythromycin are the preferred drugs for treating campylobacter infections. Of 114 C. jejuni strains tested from meats, 18% were resistant to ciprofloxacin, and 5% were resistant to erythromycin. Among the 78 C. coli isolates tested, 29% were ciprofloxacin resistant, and 37% erythromycin resistant. Among human isolates, 83% were C. jejuni and 11% were C. coli. Overall, 12% were resistant to ciprofloxacin and 6.4% were resistant to erythromycin.

For Salmonella, 154 unique retail meat isolates and 318 human isolates from the same time period were examined. Overall, Salmonella were detected in 13% of meats. Salmonella was found in ground turkey (41%) more often than chicken breast (12%), ground beef (2%) or pork chops (0%). In meats, S. Heidelberg was the most common serotype (31%), followed by S. Saintpaul (14%), S. Reading (8%), S. Hadar (8%) and S. Typhimurium (5%). Multiple-antibiotic resistance was common in human, chicken and turkey isolates. Some overlap in serotypes and genetic types was seen in the human and meat isolates.

These results indicate that Salmonella and Campylobacter, including antimicrobial resistant variants, are common in retail raw meats. These findings indicate the need for ongoing surveillance of foodborne bacterial pathogens in retail food of animal origin. This study also highlights the importance of kitchen hygiene and proper cooking to reduce the chance of infection in the home.