Prevalence and Molecular Epidemiology of Imipenem-Resistant Pseudomonas aeruginosa Carrying Metallo-Beta-Lactamases from Two Central Hospitals in Portugal

Abstract

Metallo-beta-lactamases (MBLs) can confer broad-spectrum beta-lactam resistance, including carbapenems. The aim of this work was to document the occurrence of MBLs in 122 imipenem-resistant Pseudomonas aeruginosa isolates collected in two Portuguese central hospitals, to determine their antimicrobial susceptibility, and to observe if there were intra- and interhospital epidemic spread. About 20.5% of these isolates presented blaVIM-2, which was found to be widespread in both hospitals. Clonal diversity was observed within hospitals, and no interhospital spread was observed. Ten of the blaVIM-2-positive isolates (44%), from both hospitals, presented one or two class 1 integrons. Two of those contained a VIM-2 gene, one from each hospital, which is indicative for the possibility of MBL gene transfer. No interhospital spread of integrons was observed. Regular screening and surveillance is needed to prevent spread of this worrisome resistance determinant.

Clonal Relatedness among Imipenem-ResistantPseudomonas aeruginosaIsolated from ICU-Hospitalized Patients

“…Similarly, Silva reported 86 distinct RAPD types (89.6% of polymorphisms) among the 96 strains isolated from clinical specimens of different Brazilian hospitals [ 41 ]. In agreement with Pereira study in two referral hospitals of Portugal, our results did not reveal epidemic spread [ 11 ]. Our results demonstrate that most of the isolates probably originated from the patients themselves; however, cross-infection of P. aeruginosa between patients is possible to occur, suggesting nosocomial infection control problem.…”

“…Molecular epidemiological methods such as Random Amplified Polymorphic DNA- (RAPD-) PCR are well suited to determination of transmission routes of P. aeruginosa in hospital wards [ 10 , 11 ]. An evaluation of the incidence of imipenem-resistant P. aeruginosa and its transmission in hospitals is of particular importance for the effective management of hospital-acquired infections.…”

High incidence of MBL-mediated imipenem resistance among Pseudomonas aeruginosa from surgical site infections in Egypt

“…Various mechanisms could be responsible for carbapenems resistance in P. aeruginosa including the decrease in the permeability of the cell-wall, intrinsic efflux systems over-expression in addition to production of hydrolyzing enzymes particularly MBLs. The presence of MBLs is responsible for about 40% of IRPA isolates all over the world; 39% in a surveillance program in Italy [29] and 40% in Portugal [30], with higher rates reported in Pakistan (764.9%) [31] and remarkably lower rates in France (5.6%) [32].…”

“…Genes encoding MBLs are mostly acquired by horizontal gene transfer carried by plasmids or transposons leading to a wider prevalence of MBLs as a cause of carbapenems resistance [37,38]. The first detected MBLs were the IMP-and VIM-type enzymes, followed by more types of acquired MBLs, including the SIM-, NDM-, SPM-, KHM-, GIM-, AIM-, DIM-, SMB-, TMB-, and FIM-type enzymes.…”

First report of the blaVIM gene in environmental isolates of Buttiauxella sp.

“…Several works (17)(18)(19) have demonstrated the presence of the bla VIM-2 gene in clinical bacteria since the first description in a clinical Pseudomonas aeruginosa isolate in France, in 1996 (20). The MBLs codified by these genes have been detected in several countries and in different species of bacteria, including P. aeruginosa and in several Enterobacteriaceae (15), however, by our knowledge, in environmental isolates just a work has reported this gene (21).…”