[Prevalence of ESBL-positive strains of Klebsiella pneumoniae in the Czech Republic and their molecular biology analysis].

BACKGROUND: One of the problems of contemporary medicine is an increasing number of bacterial strains with hazardous phenotypes of resistance. The feared bacterial pathogens include Klebsiella pneumoniae strains producing AmpA extended-spectrum beta-lactamases. The study focused on the molecular biological characteristics of ESBL-positive strains of Klebsiella pneumoniae collected in the Czech Republic. MATERIALS AND METHODS: Clinical material from patients hospitalized in 16 Czech hospitals in September and October 2004 was used to isolate and determine Klebsiella pneumoniae strains by standard identification procedures. Their susceptibility to antibiotics was tested using a dilution micromethod. A Double-Disk Synergy Test was used for phenotype determination of ESBL production. The blaTEM, blaSHV and blaOXA genes coding ESBL production were demonstrated by PCR. Molecular biological characteristics of ESBL-positive strains utilized the genomic DNA isolation, XbaI restrictase digestion and PFGE differentiation. The acquired restriction maps of individual isolates were compared using GelCompar II software and their relationship was determined. RESULTS: During the monitored period, 913 Klebsiella pneumoniae strains causing clinically detectable diseases were isolated. Of these, 234 (25.6 %) were determined as ESBL-positive strains. The prevalence of ESBL-positive strains was 38.5 % in ICUs and 15.8 % in standard wards. More than 50 % of ESBL-positive isolates were effectively treated only with meropenem (98 %), cefoperazone/sulbactam (61 %) and amikacin (54 %). Conversely, ESBL-negative strains showed high susceptibility to all tested antibiotics (76-99 %). The molecular biological analysis identified 18 clonal types containing 2-6 identical strains. 17 clones usually contained isolates from one hospital and only in one clone strains from two hospitals were identified. CONCLUSION: Based on the above mentioned results, the prevalence of ESBL-positive strains of Klebsiella pneumoniae in the Czech Republic can be perceived as relatively high, especially in the ICUs. An extensive spread of epidemic clones within Czech hospitals and, to a limited extent, between them can be demonstrated.