Urinary Tract Infections Likely Caused by Tainted Food

A multi-state outbreak of urinary tract infections caused by drug-resistant Escherichia coli was probably due to consumption of a contaminated food product of animal origin, such as meat or milk, according to an article in the Jan. 15 issue of Clinical Infectious Diseases, now available online.

Urinary tract infections, or UTIs, are one of the most common infections in women. Although they are not typically considered “outbreak” diseases, it is likely that a cluster of UTIs resulting from the same drug-resistant strain of the bacterium E. coli came from a single source, such as a food animal.

Between October 1999 and January 2000, a single strain of E. coli was discovered to be responsible for drug-resistant UTIs in university communities in California, Minnesota, and Michigan. Researchers studied nearly 500 specimens of E. coli obtained from non-human sources such as cows, turkeys, dogs, sheep, and water. They found that one-quarter of the specimens were microbiologically indistinguishable from comparable human strains of E. coli. A more refined test showed that, of the drug-resistant specimens, one from a cow had a 94 percent similarity to a UTI-causing human strain of E. coli. The researchers concluded that the cause of the outbreak was probably foodborne.

Bacterial drug resistance due to unnecessary antibiotic usage is a growing problem in health care, according to many experts. “People just have to be more conscious of when to use antibiotics for which infections,” said lead author Lee W. Riley, MD, of the University of California-Berkeley. “Sometimes the use of these drugs may not be necessary.” However, when drug-resistant organisms originate in animals, “there’s not much people can do” to combat the increasing drug resistance, he added. Instead, foodborne illnesses are best avoided by smart food preparation. “The consumer has to be aware that foods can be infected and has to be careful in preparing food” by cooking it thoroughly, Dr. Riley said.

Sensible food preparation can help avert a host of health problems, such as diarrhea, cramping and fever; apparently, UTIs should now be added to the list. “Urinary tract infection … has never been thought of as being food-related,” Dr. Riley added. He feels, however, that since the study shows a connection, “then the problem of foodborne disease is much greater in scope than we had ever previously thought.”