[Extended-spectrum beta-lactamase production and antimicrobial resistance patterns of Klebsiella pneumoniae strains isolated from nosocomial bacteremic patients: evaluation of the results of 2001-2005 period].

Extended spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae is a global health problem. This study was aimed to retrospectively evaluate the resistance patterns of K. pneumoniae strains, microbiologically proven as agents of nosocomial bacteremia, between 2001-2005 and also to compare the 2001-2002 and 2004-2005 data to investigate the effect of 2003 budget application on antimicrobial resistance in our country. Data of antimicrobial resistance and hospital admission dates were extracted from the hospital patient record database. 2003 data was excluded to better evaluate the probable effect of governmental antibiotic restriction policy, which was started in March 2003. Blood cultures were performed on Bact/Alert (bioMerieux, Durham, NC) automated system and bacterial identifications were done by conventional methods. Double or more isolates during each episode were counted as one episode. Antibacterial susceptibility testing was done by disc diffusion method according to the recommendations of Clinical Laboratory Standards Institute. Resistance patterns in the 2001-2002 and 2004-2005 periods were compared by chi-square test. No resistance to carbapenems were detected in the strains. The comparison of 2001-2002 and 2004-2005 periods revealed that resistance to amikacin (30% and 19%, respectively), cefuroxime (55% and 37%, respectively), amoxycillin/clavulonate (59% and 46%, respectively), piperacillin/tazobactam (51% and 39%, respectively) and cotrimoxazole (53% and 35%, respectively) were decreased significantly (p < 0.05). The rate of ESBL K. pneumoniae strains was 49% in 2001-2002 period while it decreased to 35% in 2004-2005 period (p < 0.025). The decrease in the resistance rates after the 2003 budget application suggested that this success could be attributed to the evaluation of each patient to be given an extended spectrum antibiotic, by an infectious disease specialist and also more active use of the clinical microbiology laboratory.