Animal & Veterinary
Understanding Annual NARMS Executive Reports
By Melanie McLean, DVM, Center for Veterinary Medicine, FDA
Annual NARMS Executive Reports summarize data on enteric bacteria that cause foodborne illness, commonly called food poisoning, in people. (Enteric bacteria are those that live in the intestines of people and animals.)
The NARMS program tracks antimicrobial resistance, also called antibiotic or drug resistance, in certain enteric bacteria throughout the U.S. Antibiotic resistance describes bacteria that are no longer susceptible to an antibiotic, meaning that the drug is less powerful for treating bacterial infections.
Antibiotic resistance occurs after bacteria are exposed to an antibiotic and continue to survive in the drug’s presence. Once bacteria become resistant to a drug, the continued use of that drug may increase the number of resistant bacteria. Public health may be affected if resistant bacteria enter the food supply and cause infections that are less responsive to therapy.
A Pattern of Threes
Established in 1996, NARMS is a partnership between three federal agencies and has three components. The program works in three phases.
- Food and Drug Administration (FDA)
- Centers for Disease Control and Prevention (CDC)
- U.S. Department of Agriculture (USDA)
- Human component
- Animal component
- Retail meat component
- First, samples are collected from the three components.
- Second, the samples are tested for certain enteric bacteria. If the samples are positive, isolates of the bacteria are collected.
- Third, the bacterial isolates are tested for susceptibility to various antibiotics that are important in human and veterinary medicine.
Scientists use the results of the susceptibility testing to see which antibiotics work against the bacteria and which antibiotics do not. This information is used to promote interventions that reduce resistance among foodborne bacteria, and to help FDA make decisions on the approval of safe and effective antimicrobial drugs for animals.
Launched in 1996, the human component of NARMS collects and tests bacterial isolates from people who are confirmed to be sick from foodborne illness. CDC conducts the antibiotic susceptibility testing.
The animal component, started in 1997, analyzes samples taken from food-producing animals, such as chickens and cattle, across the U.S. The samples are tested for the same foodborne bacteria as the other parts of NARMS. Launched in 2002, the retail meat component analyzes retail meats, such as chicken breasts and ground beef. State public health laboratories culture the meat for specific enteric bacteria and send them to CVM’s Office of Research for further analysis, including antibiotic susceptibility testing.
What’s in the Report?
The NARMS Executive Report describes the methods for collecting samples from each of the three components. The report also provides detailed data, in table and graph format, on three groups of enteric bacteria collected from people, food-producing animals, and retail meat:
- Non-typhoidal Salmonella
- Escherichia coli
Non-typhoidal Salmonella are a group of bacteria that can cause diarrheal illness in people. Salmonella are sometimes found in the intestines of people and animals. People become infected with the bacteria by eating foods contaminated with animal feces. Contaminated foods are often of animal origin, such as beef, poultry, milk, or eggs, but any food, including vegetables, may become contaminated. (Typhoidal Salmonella, on the other hand, live only in people. These bacteria cause the disease typhoid fever. People get typhoid fever by coming into contact with the feces of an infected person.)
The foodborne illness caused by non-typhoidal Salmonella is called salmonellosis. People with salmonellosis develop diarrhea, fever, and abdominal cramps. The diarrhea can become severe. The illness may be life-threatening in some groups, such as children, the elderly, and people with compromised immune systems.
Campylobacter bacteria cause the foodborne illness campylobacteriosis in people. Campylobacter is well-adapted to live in the intestines of birds. Most cases of campylobacteriosis are associated with eating raw or undercooked poultry products, or if these products cross-contaminate other food.
Campylobacter is one of the most common causes of diarrheal illness in people in the U.S. The diarrhea may be bloody and can be accompanied by nausea and vomiting. Other symptoms include cramping, abdominal pain, and fever.
Escherichia coli, better known simply as E. coli, are bacteria that normally live in the intestines of people and animals. Although most E. coli strains are harmless, some are pathogenic (disease-causing). The pathogenic E. coli strains cause a variety of health problems in people, including diarrhea, urinary tract infections, respiratory illness and pneumonia, and other illnesses. People get E. coli from eating food that is contaminated with human or animal feces.
For each group of enteric bacteria, the NARMS Executive Report includes information such as the:
- Number of retail meat samples tested, and the number and percent positive
- Number of isolates tested, arranged by source and year
- Antibiotic resistance among isolates collected from people, retail meat, and food-producing animals, arranged by year
- Multidrug resistance patterns, arranged by year (Multidrug resistance is when two or more types, or classes, of antibiotics don’t work against a bacteria.)
The Executive Report is available on the FDA NARMS website. The report is accompanied by interactive displays that allow users to compare resistance trends across sources for each pathogen and drug. Users are also able to download resistance graphs and tables for their own publications and presentations. The 2009 Executive Report is the first report that is accompanied by a summary. The 2009 Executive Summary contains data highlights from the Executive Report.
Please contact Dr. Heather Tate for any assistance with interpretation of the Executive Report.