Study finds “surprisingly high” antibiotic resistance among urine isolates of E. coli in the United States

There was a “surprisingly high” level of antibiotic resistance in the urine of outpatients Escherichia coli isolates collected over a recent 9-year period in the United States, according to a study published in Clinical infectious diseases.

“These data demonstrate the high prevalence of non-susceptible E. coli, with significant variation in resistance depending on geographic location in the United States for patients presenting to outpatient clinics with uncomplicated urinary tract infection ”, Infectious Disease News Member of the Editorial Board Keith S. Kaye, MD, MPH, professor of internal medicine and research director in the infectious disease division at the University of Michigan medical school, Healio said.

“Awareness of local and regional rates of antimicrobial and multidrug-resistant (MDR) resistance) E. coli may help inform empirical prescribing of UTI for clinicians treating outpatient urinary tract infections, ”said Kaye. “The results of this study also highlight the need for appropriate use of antibiotics and the need for new oral agents active against resistant strains of E. coli. “

Keith S. Kaye

Kaye and colleagues rated 1,513,882 E. coli isolates collected from 2011 to 2019, examining their sensitivity to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolones and nitrofurantoin.

They found that the prevalence of E. coli isolates resistant to TMP-SMX, fluoroquinolones and nitrofurantoin were 25.4%, 21.1% and 3.8%, respectively. Through further modeling, they also observed “significant variation” in antibiotic resistance between different census regions (P <.001>

Kaye said the study’s limitations included a lack of standardized susceptibility testing.

“While all laboratories in the United States strive to follow [Clinical & Laboratory Standards Institute] and American Society for Microbiology guidelines, sensitivity results were based on local laboratory practices and reports, meaning there was a potential for variation in ratios between study laboratories, ” did he declare. “Nonetheless, the average clinician relies on the results of their microbiology lab to guide their clinical decisions, and therefore, this assessment reflects real-world information that is used to guide treatment options.”