Antimicrobial resistance in bacteria is an emerging and increasing threat to human health. Physicians should be aware that antimicrobial resistance is increasing in foodborne pathogens and that patients who are prescribed antibiotics are at increased risk for acquiring antimicrobial resistant foodborne infections. In addition, “[i]increased frequency of treatment failures for acute illiness and increased severity of infection may be manifested by prolonged duration of illness, increased frequency of bloodstream infections, increased hospitalization or increased mortality.”[1]
The use of antimicrobial agents in the feed of food animals is estimated by the FDA to be over 100 million pounds per year. Estimates range from 36% to 70% of all antibiotics produced in the United Sates are used in a food animal feed or in prophylactic treatment to prevent animal disease. The use in of antibiotics is thought to promote growth and to prevent disease on in beef, pig, turkey and chicken production as well as fish farms and some fruit and vegetable farming.[2]

According to the National Antimicrobial Resistance Monitoring System (NARMS), Campylobacter has been recovered from 47% of chicken breasts tested in recent studies. 15% of the Campylobacter jejuni and 9% of Campylobacter Coli isolated were resistant to ciprofloxacin and 20% of Campylobacter Coli were resistant to erythromycin. In a case-control study of fluoroquinolone-resistent Campylobacter infections, domestically (within the US) acquired infections were ten times more likely to have eaten poultry at a commercial establishment. The FDA recently concluded that thousands of people each year acquire Campylobacter infections that are resistant to fluoroquinolones.[3] Many of these illnesses are likely tied to consumption of animals feed antibiotics.
In the same NARMS studies, five mulit-drug resistant strains of Salmonella Newport were recovered from ground beef, ground turkey and pork chops. According to the report, “[a]ntimicrobial resistance among these foodborne bacteria is not uncommon and often associated with the use of antimicrobial agents in food animals.”[4] Ceftriaxone-resistant Salmonella has also been reported (Fey et al., 2000). The emergence of multidrug-resistant Salmonella typhimurium in the United States is another example of a drug-resistant bacteria spreading from animals to humans (Glynn et al., 1998).
The use of antibiotics in feed for food animals, on animals prophylactically to prevent disease, and the use of antibiotics in humans unnessarily must be reduced. European countries have reduced the use of antibiotics in animal feed and have seen a corresponding reduction in antibiotic-resistant illnesses in humans.[5]
[1] Angulo F.J., Nargund V.N., and Chiller T.C., Evidence of an Association Between Use of Anti-microbial Agents in Food Animals and Anti-microbial Resistance Among Bacteria Isolated from Humans and the Human Health Consequences of Such Resistance (2004)
[3] Anderson A.D., Nelson M., Baker N.L., Rossiter S., Angulo F.J., Public health consequences of use of antimicrobial agents in agriculture. Risk Management Strategies: Monitoring and Surveillance 2002
[4] Stevenson J.E., White D.G., Torpey III D.J., Craig A.S., Smith K.E., Park M.M., Pascucilla M.A., Anderson A.D., and the NARMS Working Group. Enhanced Surveillance for Antimicrobial Resistance Among Enteric Bacteria: NARMS Retail Food Study. International Conference of Emerging Infectious Diseases. Atlanta, GA, March (2002).
[5] Angulo F.J., Baker N.L., Olsen S.J., Anderson A., Barrett T.J., Antimicrobal Use in Agriculture: Controlling the Transfer of Antimicrobal Resistance to Humans (2004).