Antibiotic resistance for foodborne pathogen

Recent studies have shown a connection between people who become infected with Campylobacter jejuni, a pathogen found in poultry, and their contact with certain chicken products that contain the pathogen. It also turns out that the Campylobacter jejuni from those products is becoming resistant to ciprofloxacin, a synthetic antibiotic used by humans to fight bacterial infections.

The prevalence of Campylobacter – which is a major cause of foodborne illness – is common on raw poultry. Of these bacteria only Campylobacter jejuni is predominantly pathogenic to humans. The US Department of Agriculture recommends thorough cooking of poultry as a safeguard against pathogenic contamination.

The situation prompted Food Safety Consortium scientists at the University of Arkansas System Division of Agriculture to examine raw chicken carcasses purchased in two Fayetteville, Ark., grocery stores each week for nearly a year.

After examining the 392 chicken carcasses, they found that 85% of the chickens purchased from one store had countable levels of Campylobacter (including its non-pathogenic species), with 27% of it resistant to ciprofloxacin. At the other store, 46% of the carcasses had detectable Campylobacter and 6% of that was resistant to ciprofloxacin.

Ramakrishna Nannapaneni, who conducted the research while at Arkansas as a food science post-doctoral associate, said that ciprofloxacin has never been used in animals. However, it is closely related to two other antibiotics, enrofloxacin and sarafloxacin, which were previously approved for usage in poultry between 1995 and 2000 before they were banned on 12 September 2005.

“When Campylobacter became resistant to enrofloxacin or sarafloxacin, it also showed cross-resistance to other fluoroquinolones (a group of antibiotics), such as in human medicine against ciprofloxacin,” said Nannapaneni, now an assistant professor of food science at Mississippi State University.

The results show a variance in the levels of Campylobacter between the two stores and also the levels of resistance to ciprofloxacin, with one store having markedly lower numbers in each category. Nannapaneni said the difference could be because of variations in packing and storage conditions at the two stores or differences in management of the poultry before harvesting.

“There is a clear need for monitoring the persistence and quantitative reduction of the total antibiotic-resistant Campylobacter loads in the food chain, particularly on raw animal food products, in efforts to control human campylobacteriosis,” Nannapaneni said.