Increasing Incidence of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae (ESBL) and the Relation to Consumption of Broad-Spectrum Antimicrobial Agents 2003-2011 in a Large Area of Copenhagen, Denmark

Purpose: To investigate 1) the development in the incidence of ESBL-producing bacteria in hospitals and primary health care, 2) the contribution of primary health care to the incidence of ESBL-producing bacteria, and 3) the development in resistance patterns for all Escherichia coli and Klebsiella pneumoniae isolates in relation to antimicrobial consumption in hospitals and primary health care. Methods: ESBL-data were retrospectively collected from bacterial isolates from all specimens received at the Department of Clinical Microbiology from 2003 to 2011 together with the corresponding patient data. ESBL-production was detected in isolates from 1067 of 59,373 patients (1.8%) with an E. coli infection and in 263 of 8660 patients (3.0%) with a K. pneumoniae infection. Results: From 2003 to 2009, an increase in patients with an ESBL-producing isolate occurred in both hospitals and primary health care at the same time as an increased consumption of broad-spectrum antimicrobial agents was seen. Interventions to reduce prescription of cephalosporins and ciprofloxacin at the hospitals from 2010 resulted in a remarkable decrease in patients with ESBL-producing K. pneumoniae whereas a continuing increase was seen in patients with ESBL-producing E. coli both at hospitals and in primary health care. The proportion of patients with community-acquired ESBL-producing E. coli was stable with an increase of only 1.4% from 2007 to 2011. Conclusions: Reduction in prescription of broad-spectrum antimicrobial agents at the hospital level had an important impact on the incidence of ESBL-producing K. pneumoniae, but not on ESBL-producing E. coli.