Objective: The aim of the study was to determine risk factors for multiresistant Klebsiella pneumoniae isolation in the critically ill patietns. Design: Prospective, observational study. Setting: The studywascarried out at the Department of Anaesthesiology and Intensive Medicine, University Hospital, Hradec Králové, Czech Republic Material and methods: All patients hospitalized with at least one positive isolation of Klebsiella pneumoniae were enrolled into the study. The exposure to antibiotics during hospitalization or one month preceding hospitalization; age; gender; APACHE II and SOFA scores on admission; day of ICU stay when sample for microbiological investigation was taken (later demonstrated to be positive for Klebsiella pneumoniae); metabolic disorder (diabetes mellitus) and underlying diagnosis were considered to be potential risk factors formultiresistant Klebsiella pneumoniae isolation. For the purpose of this study the index of insusceptibility (IN) was designed to evaluate multiresistance. Risk factors were investigated by means of univariant and multinominal linear regression analyses. A P value below 0.05 was considered statistically significant. Results: Exposure to aminoglycosides (P=0.033), carbapenems (P=0.043) as well as underlying diagnosis – respiratory tract diseases (IDC-10 version) (P=0.002) were found to be independent predictors of multidrug-resistant Klebsiella pneumoniae strain isolation. Conclusion: Antibiotic selection pressure plays an important role in colonization/infection of critically ill patients by multidrug-resistant bacterial strains.

        Key words: Klebsiella pneumoniae – multidrug resistance – selection pressure – antibiotics – intensive care