Contaminated food can lead to urinary tract infections in women | Science Blog:
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.
Expand that. They took the samples, made a phylogeny, and found that the samples from women with urinary tract infections shared the most characters with the samples from cows. E. coli
evolves randomly and through selection, like everything else, and these researchers used that to identify the culprit in many infections. Thanks evolution.