Despite drop in ciprofloxacin use, resistant E. coli rises

After a nearly threefold drop in prescriptions for the antibiotic ciprofloxacin between 2015 and 2021, the rates of ciprofloxacin-resistant E. coli bacteria circulating in the community did not decline.

A study of Seattle-area women over age 50 who had not taken any antibiotics for at least a year discovered that the incidence of gut-colonizing ciprofloxacin-resistant E. coli actually increased. About 1 in 5 women in the study were affected. In the study, the scientists examined participants’ positive samples to determine which antibiotic-resistant strains of E. coli were present.

They found that the rate of a particularly virulent strain, ST1193, rose during the study period. Together with E. coli strain ST131-H30, these strains are the major causes of a global pandemic of multi-drug-resistant urinary tract infections among all women. If ST1193 makes its home in more people’s guts, the situation could lead to more urinary tract infections with this more virulent strain, regardless of the curbing of fluoroquinolones prescriptions.

Another strain with a troubling increase in the participant samples was ST69, known to more frequently cause urinary tract infections in children. The study findings suggest that scientists should prioritize discovering better ways to control drug-resistant E. coli’s ability to colonize the gut before it causes these infections, the authors wrote. They mentioned potential strategies for deploying probiotic bacteria and anti-bacterial viruses (bacteriophages).

Reference: Increase in the community circulation of ciprofloxacin-resistant Escherichia coli despite reduction in antibiotic prescriptions, Communications Medicine, DOI 10.1038/s43856-023-00337-2