US poultry integrators asked to participate in on-farm NARMS study

NationalAntimicrobial Resistance Monitoring System pilot program will evaluate Salmonellaand Campylobacter isolated from poultry house environmental samples.

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Salmonella and Campylobacter samples will be taken on poultry farms for the National Antimicrobial Resistance Monitoring System.
Salmonella and Campylobacter samples will be taken on poultry farms for the National Antimicrobial Resistance Monitoring System.

U.S. turkey and chicken integrators are being asked to take part in a pilot study to evaluate the antimicrobial resistance levels of Salmonella and Campylobacter isolated from poultry house environmental samples. 

The National Antimicrobial Resistance Monitoring System (NARMS) monitors antimicrobial susceptibility in enteric bacteria from humans, retail meats and food-producing animals. Started in 1996, NARMS is a collaborative effort among FDA, USDA and CDC. For evaluating poultry, NARMS has utilized the samples collected by USDA Food Safety and Inspection Service (FSIS) inspectors when it tests post-chill carcasses for the presence of Salmonella and Campylobacter.

As the poultry industry has gotten better at removing Salmonella and Campylobacter from carcasses during processing, the concern was raised that the samples of Salmonella and Campylobacter that recovered at the chiller might not be providing a true random sample of the microorganisms that are present on the birds. For instance, the samples collected at the chiller might be biased toward those strains that survive well in the processing plant or be the result of cross contamination and not provide a true random sample of what is in the poultry house.

Pilot testing of alternatives

In 2007, a committee reviewed the NARMS programs and made some recommendations for changes. One of the recommendations was to conduct pilot studies to collect animal drug use and resistance data on-farm to assess the feasibility of a pre-harvest sampling approach for NARMS in dairy and feedlot cattle, poultry and swine. Dr. Charles Hofacre, Department of Avian Medicine, University of Georgia, said that three years ago he and Dr. Randall Singer, Department of Veterinary and Biomedical Sciences, University of Minnesota, were asked if it was possible to take samples at the farm.

Hofacre and Singer collaborated on a small-scale pilot study where an individual walks through a broiler or turkey house in the week prior to marketing wearing a boot sock to collect an environmental sample. Four hundred broiler and 100 turkey houses were sampled over a roughly 12-month period in 2011 and 2012. Hofacre said Salmonella was found in 22 percent of broiler house samples and 40 percent of turkey samples. Campylobacter was found in 67 percent of broiler house samples and 20 percent of turkey samples. The antimicrobial resistance levels of all the Salmonella and Campylobacter isolates were also tested. Based on the results of the pilot study, a larger study will be conducted in 2014. 

In addition to the boot sock pilot study, FSIS is conducting a study where inspectors pull ceca from eviscerated birds at the processing plant. Salmonella and Campylobacter isolated from the ceca of broilers and turkeys are then being tested for antimicrobial resistance. Hofacre said that the initial ceca study has not been completed. For now he said the boot sock and ceca studies will be conducted in parallel.

Integrator participation needed

In order to get truly random samples of the broilers and turkeys raised in the U.S., Hofacre said it is hoped that all U.S. turkey and chicken integrators will agree to participate in the upcoming pilot boot sock study. The project protocol calls for each participating poultry complex to be given a number, and each week a complex will be randomly selected. When a complex's number is drawn, they are asked to sample eight farms that will be marketed in the succeeding week. Four boot sock samples are to be collected, one per house, from each of the eight farms.

Hofacre said the boot socks are stored on ice prior to sampling, and after they are worn in the house, they are shipped to the lab overnight on ice. Integrators are asked to take the samples early in the week so that they are returned to the laboratory before the weekend. The University of Minnesota will culture all the turkey house samples and some of the broiler house samples, and the University of Georgia laboratory will concentrate on broiler house samples. 

In addition to collecting the boot sock samples, the poultry company will be asked to fill out a survey form that asks questions about antibiotic use on the sampled farms. The project will begin in January 2014 and run for the entire year. 

Protecting confidentiality

Funding for the study comes from FDA, but the money will be funneled through USDA. USDA has established a Cooperative Research and Development Agreement (CRADA) for the NARMS work. Hofacre said the U.S. Attorney General has determined the CRADAs are Freedom of Information Act (FOIA) proof. In addition, all of the samples are funneled through the diagnostic laboratories of the respective veterinary schools, and Hofacre said patient-client confidentiality covers the samples at these laboratories. 

The samples are only identified by a number, and only one computer will have the code. The database will not keep information in a uniform pattern, so it will look random and can't be traced back to an individual company, according to Hofacre. 

Individual participating companies may decide whether they want to be given the results of their own samples. The industry will be given the total study information before it is released to the public. Hofacre said NARMS data will be gathered on the farm, whether the poultry industry cooperates or not. He suggested that the poultry industry would be better able to respond to the data if it participates in the study.

Why Salmonella and Campylobacter?

Bacteria and other microorganisms produce antibiotics to fight off their neighbors, and they have evolved to protect themselves from antibiotics. This has happened naturally for millions of years. Hofacre said some microorganisms adapted to live in the guts of chickens can't survive as well in people because of the six- to seven-degree difference in body temperatures between people and chickens.

"In reality, the only organisms that have a chance of transferring their resistance genes to the organisms in your gut are the organisms that can live in the chicken and in you," he said. "It takes a special type of organism, like Salmonella or Campylobacter, to be able to survive at those two different temperatures. An organism can't pass along antibiotic resistance if it isn't able to survive in your system." 

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