Clinical Epidemiology and Risk Factors for Community-Onset Isolation of Extended-Spectrum β-Lactamase-Producing...

Community-onset isolation of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBLEC) from clinical specimens is an increasing public health concern. We aimed to identify healthcare- and community-associated factors associated with community-onset ESBLEC isolation in Japanese adults.

We conducted a case-control study at two tertiary care hospitals in Japan, combining chart review with a structured questionnaire. Adults with community-onset ESBLEC isolated in an outpatient setting or within 3 days after admission were enrolled as cases, and adults with community-onset third-generation cephalosporin-susceptible E. coli served as controls. Multivariable logistic regression was used to identify the independent factors associated with ESBLEC isolation.

In total, 124 patients, comprising 57 cases and 67 controls, were included. Chart-derived antibiotic exposure within one year (adjusted odds ratio [aOR], 2.68; 95% CI, 1.07-6.72) and self-reported history of antimicrobial-resistant organism detection within one year (aOR, 5.13; 95% CI, 1.24-21.25) were independently associated with ESBLEC isolation. An exploratory inverse association was observed for handwashing before toilet use (aOR, 0.24; 95% CI, 0.06-0.90), but this association was not statistically significant in the sensitivity analysis restricted to soap or alcohol use. Readmission within 30 days was more frequent among cases (5/41 [12.2%] vs. 0/48 [0.0%]); none of the five readmissions was attributed to ESBLEC-related infection.

Prior antibiotic exposure and a history of antimicrobial-resistant organism detection were the principal independent correlates of community-onset ESBLEC isolation. The inverse association with pre-toilet handwashing should be considered exploratory and hypothesis-generating and warrants confirmation in larger prospective studies.