Clinical Microbiology and Antimicrobial Chemotherapy. 2012; 14(2):132-152
The prevalence and molecular epidemiology of MBLproducing Gram-negative bacteria have been studied in Russia (1998–2010), Belarus and Kazakhstan (2005– 2010). Analysis of nosocomial strains isolated as part of several multicentre surveillance studies in Russia revealed rapid increase in prevalence of MBL-positive Pseudomonas aeruginosa isolates (from 4,5% to 20,3% between 2002–2004 and 2006–2007), which was mainly due to epidemic spread of P. aeruginosa clone ST235 VIM-2. Circulation of this clone was noted across Russia as well as in several cities of Belarus and Kazakhstan. ST235 comprised 96,3% of all (n=711) MBL-producing P. aeruginosa, the remaining isolates belonged to unrelated sequence-types: ST234 (3,4%), ST244 (0,1%) and ST270 (0,1%). Most isolates were susceptible only to polymyxins. In P. aeruginosa, five different types of integrons harbouring the genes for MBLs: VIM-2 (99,6%) and IMP-30, a new Glu59/Lys variant of IMP-1, (0,4%) were found. A likely horizontal transfer of the most prevalent Tn5090-associated integron carrying the blaVIM-2 gene cassette from ST235 to ST234 and ST244 was observed in two cases. In addition to P. aeruginosa, production of MBL (VIM-4) was detected in a single isolate of Escherichia coli.