Detection of Pseudomonas aeruginosa Producing Metallo-β-Lactamases in a Large Centralized Laboratory

Abstract

Metallo-␤-lactamases (MBLs) have been increasingly recognized from clinical isolates worldwide, but the laboratory detection of these strains is not well defined. We report a study that developed an EDTA disk screen test and a molecular diagnostic assay for the detection of MBL-producing Pseudomonas aeruginosa. Using NCCLS disk methodology, inhibition zone diameters were determined in tests with imipenem (IPM) and meropenem (MEM) disks alone and in combination with 930 g of EDTA. This test was compared with the MBL Etest. The duplex PCR assay showed 100% sensitivity and specificity for detecting MBL-producing control strains. Of the 241 clinical strains of IPM-nonsusceptible P. aeruginosa from the Calgary Health Region isolated from 2002 to 2004, 110/241 (46%) were MBL positive using phenotypic methods while 107/241 (45%) were PCR positive for MBL genes: 103/241 (43%) for bla VIM and 4/241 (2%) for bla IMP . The EDTA disk screen test using MEM showed 100% sensitivity and 97% specificity for detecting MBLs in control and clinical strains. The EDTA disk screen test is simple to perform and to interpret and can easily be introduced into the workflow of a clinical laboratory. We recommend that all IPM-nonsusceptible P. aeruginosa isolates be routinely screened for MBL production using the EDTA disk screen test and that PCR confirmation be performed at a regional laboratory.Pseudomonas aeruginosa producing metallo-␤-lactamases (MBLs) was first reported from Japan in 1991 (43) and since then has been described from various parts of the world, in-

Multidrug-resistant Acinetobacter baumannii strains carrying the blaOxA-23 and the blaGES-11 genes in a neonatology center in Tunisia

“…DNA in supernatant was used as a template under standard PCR procedure [9] with a series of different sets of primers. Detection of the known acquired CHDLs (bla OxA-23, bla , and bla OxA-58 ) [14], class A extended-spectrum b-lactamases (bla PER , bla VEB , and bla GES ) [14,15], MBL (bla IMP , bla VIM , bla SIM , bla NDM ) [16,17] and the intrinsic bla OxA-51-like gene was performed as previously described [14].…”

Prevalence of Metallo-beta-Lactamase producing Pseudomonas aeruginosa in wound infections in Duhok city, Iraq

“…This data is already similar to other data. 10,14,15 As a general, results from present study indicate that infections associated with multi-resistant MBL-producing P. aeruginosa in wounded patients might be associated with significantly greater morbidity, mortality and cost of care in study area.…”

“…This is already reported in other studies. 10,14,15,21 This coresistance might be due to MBLs encoding is largely association with mobile genetic elements that often carry other resistance genes, resulting in multidrug resistance (MDR). 22 The later observation insight great importance and implies that these antibiotics are no longer be effectively used as empirical therapy for these so-called "superbugs" MBL producing P. aeruginosa infections and reflects a threat limiting the treatment options in our hospitals.…”

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

“…Colistin-only susceptible P. aeruginosa is a relatively contemporary issue, once carbapenems remained as effective therapeutic choice until the carbapenemases emergence on the last two decades. 7,8,14 Investigating MBL-encoding genes, we found isolates carrying bla SPM and bla IMP genes that together correspond to 29.8% of evaluated samples. In Brazil, the dissemination of P. aeruginosa carrying bla SPM gene has been reported throughout from several regions, 15,16 and SPM is the prevalent MBL among the isolates, although other enzymes have also been described, but with low frequency.…”

“…In spite of the high cost, MBL E-test strips can be employed to detect the MBL-producing P. aeruginosa due its high sensibility and specificity. 8 Despite the recommendation for screening and confirming carbapenemase production in Enterobacteriaceae, CLSI document M100-S20 11 made no mention of detecting this enzyme on non-fermentative Gram-negative bacteria. 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.…”