Background: 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 during the last 2 years.
Materials and methods: We investigated all P aeruginosa strains derived from Transplantation Institute patients, hospitalized from January 2007 to December 2008. E-tests as well as the three-discs method with imipenem, ceftazidime were used for MBL detection. For the chosen strains, a PCR method was applied for detection of genes determining VIM, IMP, and SMP.
Results: Among 311 isolated strains from 228 patients only one strain was used for each patient. We showed increased resistance to carbapenems among P aeruginosa in 2008 compared with 2007: from 14% to 22%. About 60% of resistant strains displayed the MBL phenotype. Upon PCR analysis, the VIM-type metallo-beta-lactamase was detected in 70% of them.
Conclusions: Despite similar numbers of P aeruginosa-infected patients in 2007 and 2008, the percentage of MBL-producing strains increased from 7% to 15%. Most MBLs belonged to the VIM type.