BALTIMORE — Johns Hopkins Bloomberg School of Public Health researchers claim to have found evidence that houseflies collected near broiler poultry operations may contribute to the dispersion of drug-resistant bacteria, increasing the potential for human exposure to drug-resistant bacteria. The findings demonstrate a potential link between industrial food animal production and exposures to antibiotic-resistant pathogens, according to the authors of the study.

Previous studies have linked antibiotic use in poultry production to antibiotic-resistant bacteria in farm workers, consumer poultry products and the environment surrounding confined poultry operations, as well as releases from poultry transport.

"Flies are well-known vectors of disease and have been implicated in the spread of various viral and bacterial infections affecting humans, including enteric fever, cholera, salmonellosis, campylobacteriosis and shigellosis," said Dr. Jay Graham, Ph.D., the lead author who conducted the study as a research fellow with Bloomberg School’s Center for a Livable Future. "Our study found similarities in the antibiotic-resistant bacteria in both the flies and poultry litter we sampled. The evidence is another example of the risks associated with the inadequate treatment of animal wastes."

"Although we did not directly quantify the contribution of flies to human exposure, our results suggest that flies in intensive production areas could efficiently spread resistant organisms over large distances," said Dr. Ellen Silbergeld, Ph.D., senior author of the study and professor in the Bloomberg School of Public Health’s Department of Environmental Health Sciences.

At least one poultry industry insider is skeptical of this study and its results. "This is the same group that did a study of bacteria allegedly flying off chickens in transport, which could be a problem if you are in the habit of tailgating chicken trucks with your windows rolled down

which nobody does," Richard L. Lobb, director of communications for the National Chicken Council, told "So they have gone from tailgating chicken trucks to catching flies."

It is interesting that the study apparently makes no connection between the flies and any human illness

"We did not directly quantify the contribution of flies to human exposure," as Dr. Silbergeld put it rather delicately, Mr. Lobb said.

"A scientific study is usually done in response to some observed phenomenon," Mr. Lobb continued. "This group at Johns Hopkins seems to be determined instead to find things they can use to criticize the poultry industry. They are literally swatting at flies."

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