Antibiotic use promotes resistant strains of Campylobacter

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Related tags: Campylobacter, Antibiotic resistance

The poultry industry's use of antibiotics promotes antibiotic
resistance among the foodborne bacteria that infect humans,
including the bacterium Campylobacter, according to a study by
researchers from the Johns Hopkins Bloomberg School of Public

The study, published in Environmental Health Perspectives, also provides evidence suggestingthat chickens raised without antibiotics are less likely to carry antibiotic-resistant strains of Campylobacter. The new data also shows that antibiotic-resistant Campylobacter can persist in poultrypopulations and products long after producers stop using the drugs. The study focused on fluoroquinolones (FQs), a class of antimicrobials used to control the bacterium Escherichia coli in broiler chickens. Baytril, which along with Sara Flox WSPwas approved for use in poultry, is the only remaining FQ still on the market. The US Food and Drug Administration is seeking to repeal approval for Baytril due to concerns that it contributes tomicrobial resistance. For the study the authors collected chicken products from Bell & Evans and Eberly Poultry, two producers who do not use antibiotics. Studies were also conducted at Tyson Foodsand Perdue Farms, two of the US's largest conventional producers using antibiotics. The conventional producers claimed to have stopped using FQs in February 2002, the authors stated. The authors began sampling chicken products in 2003. All samples were obtained from grocery stores in or near Baltimore, Maryland. Campylobacter was detected on 84 per cent of allthe samples tested. FQ-resistant strains were detected on 17 per cent of the samples using unsupplemented agar and on 40 per cent using supplemented agar. "Abstention from FQ use by poultry producers did not increase the likelihood of Campylobacter contamination," the authors conclude. Moreover, conventional productswere up to 460 times more likely to carry resistant strains than their antibiotic-free counterparts. Of particular interest is that FQ resistance in conventional products persisted for one year aftercessation of industrial use. Based on the findings, the authors state that even without antibiotics, resistant populations may remain prevalent in the chicken over time. The resistant populations ofCampylobacter may result from residual contamination in poultry houses, they suggest. "For example, biofilms in water distribution systems can harbour Campylobacter and thus could serve as reservoirs for resistant populations," they suggest. "Thesefindings suggest the need to further improve poultry house cleaning and disinfection." To prevent drug resistant Campylobacter strains from appearing chicken producers should measure the prevalence of FQ-resistant strains in the food supply. Supplemented agarmay provide a much more sensitive tool than conventional methods for detecting the resistant strains of the bacterium. Campylobacter is one of the most common bacterial causes of diarrheal illness in the US. The bacteria causes campylobacteriosis in humans and can result in diarrhea, cramping, abdominal pain, andfever within two to five days after exposure to the organism. Some persons who are infected with Campylobacter don't have any symptoms at all, according to the US department of health. In persons who are already ill, Campylobacter occasionally spreads to thebloodstream and causes a serious life-threatening infection. Campylobacteriosis is estimated to affect about million persons every year in the US, or 0.5 per cent of the general population.

Related topics: Food Safety & Quality

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