ExPEC of Humans and Animals

Extraintestinal pathogenic Escherichia coli (ExPEC) are a remarkably versatile group of bacteria. They are the cause of common diseases like urinary tract infections, bloodstream infections, and pneumonias. They live in the gastrointestinal tract but have the ability to colonize and cause disease in other tissues. They are difficult to treat and are becoming more resistant to antibiotics.

Many ExPEC strains can cause disease in multiple hosts, including humans, poultry, swine, and companion animals. They infect chickens and turkeys, where they cause avian colibacillosis – a major problem for poultry producers and also a source of food-borne urinary tract infections. We have recently discovered that some mastitis-associated E. coli from dairy cattle also belong to the ExPEC family. Mastitis is a very costly disease in the dairy industry and the E. coli that cause mastitis aren’t very well understood.

1. We are investigating the pathogenesis of mastitis infections. Since these bacteria are distributed in manure that fertilizes fruits and vegetables, enter irrigation or recreational waters, we are also interested to know how often these bacteria colonize humans.

2. ExPEC must interact with many other bacteria in these agricultural settings. We hope to identify and harness the abilities of some strains to outcompete or kill other strains in these environments.

3. We are investigating why some ExPEC are adept at infecting multiple hosts. We’ve discovered that for some strains, their versatility is tied to their ability to make capsules. We are defining the genetic requirements for capsule production by some mastitis-associated ExPEC strains, and identifying regulatory signals that control capsule synthesis.