Pathogenic E. coli may spread through casual contact

San Francisco-How uropathogenic Escherichia coli spreads within families is a continuing question for both practicing urologists and researchers. It has long been known that sexual contact may spread specific strains. A new study examining members of a single family confirms that casual contact between family members and even pets can also contribute to the transmission of E. coli, leading to cystitis and possibly other urologic infections.

"This study really confirms suspicions that everyday contact within a family can spread E. coli," said study co-author Connie R. Clabots, MS, from the University of Minnesota, Minneapolis. "Based on what we saw in this particular family, any contact whatsoever may be sufficient to spread E. coli."

Clabots was part of a research team led by James Johnson, MD, infectious disease specialist at the Minneapolis Veterans Administration Medical Center. The group began sampling for E. coli from all household members within 24 hours of the onset of cystitis symptoms, then repeated the sampling 3 weeks later and 7 to 9 weeks after the baseline sample.

Mother's clone most common

The mother's initial urine clone, which was also her predominant fecal clone, also emerged as the most widely spread clone in the household. It was recovered from multiple hosts at all three sampling points and was one of just two clones recovered from the family dog.

This original clone disappeared from the mother following treatment with ciprofloxacin (Cipro, Proquin), but remained on the other family members through the third sampling. None of the other household members experienced cystitis or any other urinary tract symptoms during the test, Clabots noted, although humans, dogs, and cats all experience UTIs due to similar E. coli strains.

In this particular family, Clabots said, the original source of the strain that caused the mother's cystitis is not known, although only the mother exhibited acute symptoms of infection.

"Household members may well act as reservoirs for E. coli that emerge as acute incidents," Clabots said. "The sharing of clones that we saw in this family suggests that transmission prevention within the household may be appropriate in order to protect vulnerable individuals from acquiring or reacquiring pathogens."