Risk factors for bloodstream infections due to extended-spectrum beta-lactamase-producing Escherichia coli.

BACKGROUND/PURPOSE: The risk factors for production of extended-spectrum beta-lactamases (ESBLs) have rarely been studied for bloodstream infections of Escherichia coli alone. A case-control study was undertaken to identify the risk factors associated with bloodstream infections caused by ESBL producing E. coli.

METHODS

From January 1, 2005 to June 30, 2007, all patients with a confirmed diagnosis of bloodstream infection caused by ESBL-producing E. coli were reviewed. Each patient was matched with one control subject who experienced ESBL-negative E. coli bacteremia during the same study period.

RESULTS

Of the 97 patients diagnosed with ESBL-producing E. coli bacteremia, six were excluded owing to incomplete follow-up and missing data. Comparisons were made between 91 patients and their controls. Multivariate analysis identified urinary catheterization [odds ratio (OR) = 6.21, 95% confidence interval (CI) = 1.91-20.25; p = 0.003], prior exposure to antibiotics (OR = 2.93, 95% CI = 1.18-7.30; p = 0.021) and previous treatment with oxyimino-cephalosporins (OR = 5.16, 95% CI = 1.03-25.79; p = 0.046) as independent predictors for bloodstream infection by ESBL-producing E. coli. Conversely, patients classified as having a community-acquired infection were less likely to acquire bacteremia caused by ESBL-producing E. coli than those caused by non-ESBL-producing E. coli (OR = 0.22, 95% CI = 0.09-0.57; p = 0.002).

CONCLUSION

More judicious use of antimicrobial agents, especially oxyimino-cephalosporins, and avoidance of urinary catheterization may decrease the possibility of ESBL-producing E. coli bacteremia in hospitalized patients.