IMPs, VIMs and SPMs: the diversity of metallo-β-lactamases produced by carbapenem-resistant Pseudomonas aeruginosa in a Brazilian hospital

Abstract

Pseudomonas aeruginosa isolates (n=183), collected from bacteraemic patients hospitalised in Sao Paulo Hospital (Brazil) during 2000-2001, were screened for susceptibility to antimicrobial agents. The polymyxins were the most active compounds (100% susceptibility), followed by amikacin and cefepime (59.0%), meropenem (57.4%), and imipenem and gentamicin (55.2%). Imipenem-resistant isolates were ribotyped and screened for production of metallo-beta-lactamases (MBLs) by PCR with primers for bla(IMP), bla(VIM) and bla(SPM). MBL production was detected in 36 isolates (19.7% of the entire collection; 43.9% of the imipenem-resistant isolates) and the MBLs included SPM-1-like (55.6%), VIM-2-like (30.6%) and IMP-1-like (8.3%) enzymes.

Molecular epidemiological survey of the quinolone- and carbapenem-resistant genotype and its association with the type III secretion system in Pseudomonas aeruginosa

“…In Brazil this problem is hih5ghly significant and some studies show a very high density of antibiotic use, especially of carbapenems and fluoroquinolones (Moreira et al, 2013;Porto et al, 2013). The resistance of P. aeruginosa to carbapenems is higher than 60 % in some Brazilian hospitals (Baumgart et al, 2010;Sader et al, 2005) and the production of metallo-b-lactamase (MBL) encoded by several genes, including bla SPM-1 , bla VIM and bla IMP , is considered the main mechanism of resistance to these antibiotics (Sader et al, 2005).Resistance to fluoroquinolone has become an increasing problem and now has the highest resistance rates in Latin American countries (Andrade et al, 2006;Sader et al, 2001), and is associated with mutations in the quinolone resistance-determining regions (QRDRs), especially the genes encoding DNA gyrase (gyrA) and topoisomerase IV (parC) (Higgins et al, 2003;Lee et al, 2005;Mouneimné et al, 1999).Recent studies have shown that a large number of genes expressed by P. aeruginosa clinical strains are implicated directly in the pathogenesis of severe infections caused by this micro-organism (Aldred et al, 2014;Bleves et al, 2010; Golovkine et al, 2014). Among these is the type III secretion system (TTSS), which delivers effector toxins (ExoS, ExoT, ExoY and ExoU) directly into host cells (Galán & Collmer, 1999;Hauser, 2009).…”

Detection of SPM and IMP metallo-β-lactamases in clinical specimens of Pseudomonas aeruginosa from a Brazilian public tertiary hospital

“…9 However, we can wonder how much longer these bacteria will persist susceptible to these remaining drugs if this selective pressure goes on. Comparing different phenotypic tests to detect MBL, we found that ceftazidime disk and mercaptopropionic acid association, in a double disk synergy test, was the most sensitive and specific assay, as it was reported by Picão et al 7 We observed that all other combinations of substrata and inhibitors (imipenem and mercaptopropionic acid; imipenem and mercaptoacetic acid; imipenem and EDTA; ceftazidime and mercaptoacetic acid; ceftazidime and EDTA) showed maximum specificities (100%), but low sensitivity to these combinations (zero to 71.4%), restricting their utilization.…”

“…Early identification of MBL in clinical specimens is important to provide correct antimicrobial therapy guidance, once appropriate therapy implementation can nullify the worst prognostic of MBL producing P. aeruginosa. 3 When detected, it is possible to avoid the dissemination of such strains among patients [7][8][9] and to avoid the MBL genetic determinants spread to different species of Gram-negative bacteria, as Enterobacteriaceae. 6 The contention of MBL producing P. aeruginosa is highly recommended, because patient-to-patient transmission may lead these strains to be endemic in such institution 3 or among different hospitals.…”

“…MBL phenotypic detection was evaluated by the double-disk synergy test (DDST) with imipenem or ceftazidime disks (Oxoid) as substrata, and mercaptopropionic acid (Sigma-Aldrich), mercaptoacetic acid (Sigma-Aldrich), or ethylenediamine tetra-acetic acid (EDTA, Sigma-Aldrich) as MBL inhibitors, according to Picão et al 7 Genotypic detection targeting to the bla SPM and bla IMP genes was carried out by polymerase chain reaction (PCR), according to protocols published elsewhere. 9 Positive and negative quality control strains were included to assess the quality of phenotypic and genotypic assays. Student's t test was carried out to compare the median MIC of positive and negative MBL strains; sensitivity and specificity were calculated for the different substrata antimicrobials and MBL inhibitors assessed in the DDST; p-values below 0.05 were considered statistically significant.…”

Phenotypic detection of metallo-β-lactamases in Pseudomonas aeruginosa and Acinetobacter baumannii isolated from hospitalized patients in São Luis, State of Maranhão, Brazil

“…In Hospital São Paulo, State of São Paulo, Sader et al 9 found a prevalence of 19.7% MPPa in blood samples. Cipriano et al 13 detected the presence of the São Paulo Metallo-β-lactamase gene (SPM) in strains of P. aeruginosa from the same city examined in the current study.…”