Many factors tied to multidrug-resistant urinary tract infections

E coli illustration
E coli illustration

CDC / Alissa Eckert

A study conducted in France suggests human, animal, and environmental exposures may all be linked with the occurrence of community-acquired, multidrug-resistant urinary tract infections (UTIs).

The findings on UTIs caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli were reported yesterday in JAMA Network Open.

While these multidrug-resistant UTIs have long been a problem in hospitals and other healthcare facilities where patients are routinely exposed to bacterial pathogens and antibiotics, the incidence of community-acquired ESBL-producing E coli UTIs has grown in recent years, with a variety of factors cited as potential culprits. ESBL-producing E coli is considered a growing public health threat because the ESBL enzyme confers resistance to multiple classes of antibiotics and makes common infections like UTIs difficult to treat.

The authors of the study say the findings highlight the importance of surveillance and mitigation strategies that take a One Health approach.

Multiple exposures cited

For the cross-sectional study, researchers used retrospective epidemiologic and microbiologic data collected in 2019 through PRIMO (Surveillance and Prevention of Antimicrobial Resistance in Primary Care and Nursing Homes), a nationwide clinical laboratory surveillance system for administrative departments in France. The isolates, which were obtained from community urine samples that were positive for E coli, were tested for antimicrobial susceptibility and ESBL production.

Quasi-Poisson regression models were used to assess associations between several ecologic factors available on government and administrative websites and the number of ESBL-producing E coli isolated from people with community-acquired UTIs. Among the factors assessed were demographic population structure, living conditions, baseline healthcare services, antibiotic consumption, animal farming density, and environmental characteristics.

Among community urine samples from 59 French administrative departments, 444,281 E coli isolates and 13,352 ESBL-producing E coli strains were identified, for an overall 3.0% prevalence rate of ESBL-producing E coli. In the multivariate analysis, consumption of fluoroquinolones (adjusted beta coefficient, .002) and tetracyclines (adjusted beta coefficient, .0002), the local percentage of children under 5 (adjusted beta coefficient, .112), overcrowded households (adjusted beta coefficient, .049), and poultry density (adjusted beta coefficient, .0001) were positively associated with ESBL-producing E coli UTIs.

Some of these factors, like fluoroquinolone use, have previously been linked to increased risk of ESBL-producing E coli colonization or infections. "The positive association of community-acquired ESBL-producing E coli UTIs with fluoroquinolones confirms the importance of efforts to reduce their consumption," the study authors wrote.

They also note that previous research has suggested household crowding may play a role in the spread of ESBL-producing E coli because of the proximity of contacts and multiple opportunities for transmission. In addition, members of households with preschool-aged children have been found to have an increased risk of intestinal carriage of ESBL-producing bacteria. And several studies have documented the presence of ESBL-producing E coli in retail chicken meat.

But other findings were more surprising. The association with tetracycline consumption was unexpected, the authors said, and it points to the need for greater stewardship of tetracyclines, which are the third most consumed antibiotic class in French primary care.

"Strategies to mitigate ESBL in the community should follow the One Health approach and address the role played by fluoroquinolones, tetracycline use, poultry density, overcrowded households, and preschool-aged children," the authors concluded.

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