[Short communication: Extended-spectrum beta-lactamase production in Klebsiella pneumoniae strains isolated from blood cultures and their antibiotic susceptibilities].

This study was carried out to detect the extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae strains isolated from blood cultures of hospitalized patients, and to determine their antimicrobial susceptibilities. A total of 102 K. pneumoniae strains isolated from blood samples were taken in the study, and ESBL production and susceptibilities to amikacin, gentamicin, imipenem, ciprofloxacin, amoxicillin/clavulonate (AMX/CA), ceftazidime, ceftriaxone, trimethoprim/ sulphametoxazole (TMP-SMX), piperacilin-tazobactam (PIP/TAZ) and chloramphenicol were investigated by using E-test (AB Biodisk, Sweden). ESBL positivity was observed in 65 (63.7%) of the isolates, and all of the strains were found susceptible to imipenem. The resistance rates of ESBL-producing isolates were detected as 27.7% for amikacin, 41.5% for chloramphenicol, 49.2% for TMP-SMX, 55.4% for ciprofloxacin and 60% for PIP/TAZ; whereas these rates for ESBL non-producers were 2.7%, 5.4%, 5.4%, 2.7%, and 13.5%, respectively. Both the resistance rates and MIC values (MIC50 and MIC90) of the tested antimicrobial agents except imipenem, were found higher in ESBL positive strains than the ESBL negative strains (p < 0.05). The results of this study, in accordance with the previous national and international reports, indicated high rate of ESBL positive K. pneumoniae and also increased rate of antimicrobial resistance in such strains. Clinical microbiology laboratories should put ESBL detection tests into practice and each hospital should determine their antibiotic treatment policies according to their data.