Summary

Background:

Increasing antibiotic resistance in the community results in greater use of empiric broad spectrum antibiotics for patients at hospital admission. As a measure of antibiotic stewardship it is important to identify a patient population that can receive narrow spectrum antibiotics.

Objectives:

To evaluate resistance patterns of Escherichia coli bloodstream infection (BSI) from strictly community-acquired infection and the impact of recent antibiotic use on this resistance.

Methods:

This single center, historical cohort study of adult patients with E. coli BSI was conducted from January 2007 to December 2011. Patients had no exposure to any healthcare facility and no chronic catheters or chronic ulcers. Data on antibiotic use during the previous 90 days was collected and relation to resistance patterns was assessed.

Results:

Of the total number of patients, 267 BSI cases met the entry criteria; 153 patients (57%) had bacteria sensitive to all antibiotics. Among 189 patients with no antibiotic exposure, 61% of isolates (116) were pan-sensitive. Resistance to any antibiotic appeared in 114 patients and 12 were extended-spectrum beta-lactamase (ESBL) producers. Quinolone use was the main driver of resistance to any antibiotic and to ESBL resistance patterns. In a multivariate analysis, older age (odds ratio 1.1) and quinolone use (odds ratio 7) were independently correlated to ESBL.

Conclusions:

At admission, stratification by patient characteristics and recent antibiotic use can help personalize primary empirical therapy.