A study conducted among women in Seattle found that, despite a nearly threefold drop in ciprofloxacin prescriptions over 6 years, the amount of fluoroquinolone-resistant Escherichia coli (FQREC) circulating in the community increased, researchers reported earlier this month in Communications Medicine.
For the study, a team led by researchers at the University of Washington School of Medicine analyzed E coli–positive fecal samples collected in 2015 and 2021 from women over the age of 50 who were enrolled in the Kaiser Permanente Washington healthcare system and hadn't taken any antibiotics for at least a year. The aim of the study was to see whether a campaign to reduce the use of fluoroquinolones (ciprofloxacin) for uncomplicated urinary tract infections (UTIs) had any impact on incidence of FQREC in the gut, which is a primary reservoir for UTI-causing E coli.
Increase in resistant gut E coli
Among the target study population, the use of fluoroquinolones was significantly higher than in the total population from 2010 through 2015 (9.2%), but it drastically declined to 3.4% from 2016 through 2021. But comparison of E coli–positive fecal samples from women in 2015 and 2021 showed that the rates of gut carriage of FQREC increased from 14.2% to 19.8%.
The increase was primarily driven by an increase in isolates from the pandemic multidrug-resistant clonal group ST1193 (from 1.7% to 4.25). The other most common clonal groups in the samples were ST131-H30 and ST69; the three combined are the major causes of multidrug-resistant UTIs in women.
The researchers also observed a doubling (from 14.1% to 31.5%) of FQREC isolates with co-resistance to third-generation cephalosporins.
"Taken together, the results of our study suggest that, while increased use of antibiotics in patients can lead to the emergence of resistant isolates, the latter can continue to spread in the community even if antibiotic use is decreased," the study authors wrote.
While increased use of antibiotics in patients can lead to the emergence of resistant isolates, the latter can continue to spread in the community even if antibiotic use is decreased.
They say the findings suggest there may be a need to expand antimicrobial stewardship efforts to include screening and decolonization of vulnerable patients who are carrying antibiotic-resistant bacterial strains in their gut.