Bacteria Collection Sheds Light On Urinary Tract Infections

"We found out that UTIs may be caused by ingesting food contaminated with E. coli," said Dr. Chobi DebRoy, director of Penn State's Gastroenteric Disease Center. Previously, this link was not established, she noted.

Senior author, Dr. Lee W. Riley, University of California-Berkeley, found that E.coli strains isolated from patients with UTIs were genetically related to E.coli strains from cows that were in the collection of strains at the Gastroenteric Disease Center. Riley and DebRoy reported their findings in a recent issue of Clinical Infectious Diseases.

About 8 to 10 million people are diagnosed with urinary tract infections each year. Women are more likely to get UTIs than men because it is easier for the bacteria to reach their bladder. Fifty percent of all women will experience at least one episode of UTIs during their lifetime. UTIs are typically treated with antibiotics.

The researchers found that the E.coli causing the UTIs matched genetically with a sample of E.coli obtained from an animal source. They used E.coli samples collected over 40 years from the center to match up the bacteria causing UTIs with bacteria found in animals. They tested E.coli samples from dogs, cows, sheep, water and turkeys. The researchers then compared the samples genetically to the UTI causing bacteria and found that a sample from a cow matched well with the E.coli found in humans.

The team also found that the E.coli causing the infections is resistant to antibiotics. The possibility that these multidrug-resistant bacteria could have an animal origin has major public health implications because of the practice of administering subtherapeutic doses of antibiotics as growth promoters in animals.

E.coli is common bacteria found in humans and animals. Thousands of E.coli live in the organs of humans and animals and provide multiple benefits such as aiding in digestion of certain nutrients. However, E.coli is also commonly associated with illnesses caused by eating undercooked beef or drinking contaminated water.

Without access to the large collection of bacteria strains from the Gastroenteric Disease Center, it would have been difficult for the researchers to carry out the research, according to DebRoy. The Gastroenteric Disease Center has been collecting E.coli samples since 1965 and is the largest repository of E.coli in North America. The center has 60,000 E.coli strains isolated from cows, birds, pigs, humans, dogs, water and the environment. The center is located in the Department of Veterinary Science, Penn State's College of Agricultural Sciences, with a web site at: http://ecoli.cas.psu.edu/

Other researchers involved in this project include: Amee Manges, assistant professor, McGill University; Sherry P. Smith, assistant professor, Medical College of Georgia; Meena Ramachandani, School of Public Health, Berkeley; and James Johnson, professor, University of Minnesota.

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The research was supported by NIH and USDA National Research Initiative Competitive Grants Programs.