Pandemic MDR E. coli strains persist in guts of healthy adult women
Researchers discovered fluoroquinolone-resistant Escherichia coli in 8.8% of fecal samples collected from healthy adult women with no recent documented UTI, mostly from two pandemic strains, according to findings published in Clinical Infectious Diseases.
“The two E. coli strains that cause the vast majority of Cipro- and multidrug-resistant (MDR) urinary and bloodstream infections in the United States and globally are actually superb gut colonizers of healthy women that did not experience UTI for at least a year and do not take antibiotics,” Evgeni V. Sokurenko, MD, PhD, professor of microbiology at the University of Washington School of Medicine, told Infectious Disease News. “Thus, the pandemic MDR E. coli, once emerged, can circulate in the community as asymptomatic gut colonizers with a very high persistency.”
Between July 2015 and December 2016, Sokurenko and colleagues collected and analyzed 1,031 fecal samples from women without a documented UTI in the previous 12 months.
They identified E. coli in 88.8% of samples, and fluoroquinolone-resistant isolates in 8.8% of all samples and 9.9% of E. coli samples, according to the study. The researchers also identified non-E. coli fluoroquinolone-resistant bacteria in 1.6% of samples.
They detected 14 distinct clonal types among the fluoroquinolone-resistant E. coli isolates, and reported that 94.5% of samples contained a single clonal type. The pandemic strains ST131-H30R and ST1193 predominated, with ST131-H30R being discovered in about half of the samples and ST1193 in about a quarter of samples.
Of the women who were identified as carriers of fecal fluoroquinolone-resistant E. coli, 74 provided follow-up urine samples. According to Sokurenko and colleagues, 26 samples were positive for E. coli growth. Of those 26 E. coli-positive urine samples, 76.9% were fluoroquinolone resistant, with the clonal type matching the original fecal samples.
The researchers also assessed UTI occurrence within 3 months of urine collection, with 45 of the 74 fecal fluoroquinolone-resistant E. coli carriers consenting to electronic medical record examination. UTI was documented for 6.7% of consenting participants.
“Knowing the presence/absence of MDR strains in the gut could be a predictive factor for the resistance profile of the clinical infection. Furthermore, decolonization of healthy carriers from the MDR strains could reduce the rate of MDR infections in those individuals, maybe in their family members and in general,” Sokurenko said. “Finally, we might need to reassess the clinical importance of asymptomatic bacteriuria in the era of pandemic MDR strains as those particular strains could put the carriers at higher than usual risk for MDR clinical infections.” – by Marley Ghizzone
Disclosures: Sokurenko reports having patent applications to detect E. coli strains and being a major shareholder in ID Genomics. Please see the study for all other authors’ relevant financial disclosures.