Influence of third-generation cephalosporin utilization on the occurrence of ESBL-positive Klebsiella pneumoniae strains


Karel Urbanek, Department of Pharmacology, Faculty of Medicine, Palacky University, Hnevotinska 3, 775 15 Olomouc, Czech Republic. Tel.: +42 058 563 2556; fax: +42 058 563 2556; e-mail:


Background: Klebsiella pneumoniae belongs to important nosocomial pathogens causing mainly hospital-acquired infections. Beta-lactam antibiotics are frequently used in the treatment of infections caused by K. pneumoniae, but by their selection pressure the bacteria become resistant. Excessive use of third-generation cephalosporins is a risk factor for the occurrence and spread of ESBL-producing bacterial strains. The goal of this study was to describe the utilization of third-generation cephalosporins and to analyse their selection pressure on K. pneumoniae in the University Hospital in Olomouc.

Methods:  Data on the utilization of antibiotics in the hospital were obtained for the period 1997–2005 from the computerized database and expressed in defined daily doses per 100 bed-days (DBD). The data were processed according to the ATC/DDD system. Klebsiella pneumoniae strains were isolated from clinical material obtained from hospitalized patients.

Results:  Consumption of third-generation cephalosporins, which was 1·79 DBD in 1997, decreased to 0·93 in 1999, remained stable until 2002, and then increased to 2·40 DBD in 2005. During the 9-year period analysed, a total of 9564 strains of K. pneumoniae were isolated. The ESBL-positive K. pneumoniae strains frequency increased from 8% to 18%.

Conclusions:  Increasing utilization of third-generation cephalosporins was associated with a statistically and clinically significant increased incidence of ESBL-positive K. pneumoniae strains.