Antibiotic resistance remains common among meat-borne pathogens, according to the annual National Antimicrobial Resistance Monitoring System report released late last week.
NARMS, which is coordinated between the U.S. Food and Drug Administration, the Centers for Disease Control and Prevention and some state laboratories, is meant to serve as a “reference point identifying and analyzing trends in antimicrobial resistance among these organisms.”
From January to December 2010, samples of retail chicken breast, ground turkey, ground beef, and pork chops were collected and tested for Salmonella. Poultry samples were also cultured for Campylobacter. Some labs also pulled samples of meat and poultry to test for E. coli and Enterococcus.
In all, NARMS collected 5,280 samples from California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, New York, Oregon, Tennessee, and Pennsylvania.
Salmonella serotypes Typhimurium, Saintpaul, and Heidelberg accounted for 44.5 percent of retail meat isolates. The prevalence of Salmonella Heidelberg — which was the subject of a massive ground turkey recall and multistate foodborne illness outbreak over the summer — among all retail meat continued to decrease, according to the report, from 22.8 to 9 percent from 2002 through 2010.
The report highlighted a number of findings that may reinforce what many public health advocates have been arguing for years: that antibiotic use in agriculture is contributing to drug resistance in bacteria. The NARMS report pointed out that third-generation cephalosporin resistance rose in chicken breasts (10 to 34.5 percent) and ground turkey (8.1 to 16.3 percent) isolates from 2002 to 2010.
This trend was a key factor in the FDA’s recent decision to limit the off-label uses of cephalosporin in food animals.
“It is likely that the extralabel use of cephalosporins in certain food-producing animal species is contributing to the emergence of cephalosporin-resistant zoonotic foodborne bacteria,” reads the FDA rule. “Resistance to certain cephalosporins is of particular public health concern in light of the evidence of cross-resistance among drugs in the cephalosporin class.”
NARMS also found that 43.3 percent of chicken breast isolates were resistant to three or more antimicrobial classes in 2010 compared to 33.7 percent in ground turkey. More than 29 percent of chicken breast isolates showed resistance to 5 or more classes in 2010. Salmonella Albert was isolated from ground turkey for the first time since 2002 and was resistant to all 8 classes of antimicrobials tested.
Salmonella isolates susceptible to all antimicrobials decreased in pork chops (50 to 35 percent) from 2009 to 2010 and multidrug resistance among Salmonella increased among chicken breasts (29 to 35.7 percent) and ground turkey (22.3 to 30.7 percent).
NARMs also noted that E. coli — which is only harmful in certain cases, but can serve as a marker for the level of contamination — is common in all retail meat products tested in NARMS.
Of 1,840 retail meats tested in 2010 for E. coli, 64 percent were culture-positive for E. coli, with pork chops having the lowest prevalence (39.8 percent) and ground turkey with the highest (80.2 percent).
Gail Hansen, senior officer for the Pew Campaign on Human Health and Industrial Farming, said the report further backed up the importance of limiting antibiotic usage in agriculture, a move that Pew and a wide range of public health groups have been pushing for years.
“It really does reinforce what decades of research has been telling us about antibiotic resistance,” said Hansen, a veterinarian. She noted that NARMS data helped FDA’s decision to limit cephalasporins: “I was stuck by how much this [resistance] has gone up.”
The full NARMS report is available here.