Introduction: During the year 2000, the 1st nationwide project (GEIH-BLEE Project 2000) on Escherichia coli and Klebsiella pneumoniae producing extended-spectrum ss-lactamases (ESBL) was carried out in Spain. The 2nd nationwide study was developed in 2006 to investigate the evolution of this problem.
Methods: A prospective multicenter study was designed, including all ESBL-producing E. coli and K. pneumoniae strains isolated at 44 Spanish hospitals between February and March 2006. Identification was verified at the coordinating centre and ESBL production was confirmed following CLSI guidelines.
Results: A total of 1021 E. coli and 162 K. pneumoniae strains were collected. ESBL-producing E. coli strains were isolated in all the participating hospitals, whereas ESBL-producing K. pneumoniae were isolated in 34. The overall percentage (range) of ESBL production among E. coli and K. pneumoniae was 4.04% (0.4-20.3) and 5.04% (0-30), respectively. In ESBL E. coli (Ec) cases, acquisition was considered community-acquired in 32%, related to health care in 36%, and nosocomial in 30%; and in ESBL K. pneumoniae (Kp) cases, acquisition by these routes was 10%, 18%, and 68% respectively. The samples most commonly showing these microorganisms were urine (77% Ec and 48.2% Kp) and wound exudate (8.6% Ec and 14.8% Kp).
Conclusions: Since 2000, the percentage of ESBL-producing strains among E. coli and K. pneumoniae isolates in Spain has increased 8-fold and 2-fold, respectively. The increase in ESBL-producing E. coli mainly occurred in isolates from outpatients, and most commonly in urine samples.