Abstract

Background: Still growing bacterial resistance was the primary cause of increased usage of imipenem and meropenem in seriously infected patients. The aim of the study was to estimate the carbapenems resistance and occurrence of metallo-beta-lactamase (MBL) production among Pseudomonas aeruginosa isolated from patients of Transplantation Institute in the last two years.
Material/Methods: All P. aeruginosa strains derived from patients of Transplantation Institute, hospitalized from January 2007 to December 2008 were investigated. To identify and determine antimicrobial susceptibilities ATB Expression and Vitek2 systems (BioMerieux) were used. For detection of the production of MBL, phenotypic methods with special E-tests (Solna, Sweden) as well as two-discs method with imipenem alone and imipenem with EDTA were applied. For the chosen strains, the PCR method for MBL detection with starters for genes determinning VIM, IMP and SMP was applied.
Results: In 2007, 162 strains from 127 patients and in 2008, 149 strains from 101 patients were isolated. In the further examinations only one isolate per one patient was taken. In 2007, P. aeruginosa strains obtained from 18 patients were resistant to carbapenems (14%) and 9 strains displayed a MBL production phenotype. In 2008, from 101 investigated strains, 23 were resistant to carbapenems (22%), and 15 of them produced MBL. In PCR reaction the VIM-type metallo-beta-lactamase was detected in 70% of isolates with MBL positive phenotype.
Conclusions: Despite of similar number of P. aeruginosa infected patients in 2007 and 2008, the percentage of MBL producing strains increased from 7% to 15%. The most of MBLs were of the VIM-type.

Keywords: Kidney Transplantation, Liver Transplantation