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Detection of VIM-2-, IMP-1- and NDM-1-producing multidrug-resistant Pseudomonas aeruginosa in Malaysia
Siew Mun Liew1, Ganeswrei Rajasekaram2, Savithri D Puthucheary1
1Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Objectives:
The increasing incidence of carbapenem-resistant Pseudomonas aeruginosa along with the discovery of novel metallo-β-lactamases (MBLs) is of concern. In this study, the isolation of MBL-producing P. aeruginosa clinical strains in Malaysia was investigated.
Methods:
A total of 53 P. aeruginosa clinical strains were isolated from different patients in Sultanah Aminah Hospital (Johor Bahru, Malaysia) in 2015. Antimicrobial susceptibility testing was performed, and minimum inhibitory concentrations (MICs) of imipenem and meropenem were determined by Etest. Carbapenem-resistant strains were screened for MBL production by the imipenem-ethylene diamine tetra-acetic acid (IMP-EDTA) double-disk synergy test, MBL imipenem/imipenem-inhibitor (IP/IPI) Etest and PCR. Multilocus sequence typing (MLST) analysis was performed for genotyping of the isolates.
Results:
Among the 53 clinical strains, 3 (5.7%) were identified as MBL-producers. Multidrug resistance was observed in all three strains, and two were resistant to all of the antimicrobials tested. Sequencing analysis confirmed that the three strains harboured carbapenemase genes (blaIMP-1, blaVIM-2 and blaNDM-1 in one isolate each). These multidrug-resistant strains were identified as sequence type 235 (ST235) and ST308.
Conclusions:
The blaIMP-1 and blaNDM-1 genes have not previously been reported in Malaysian P. aeruginosa isolates. The emergence of imipenemase 1 (IMP-1)- and New Delhi metallo-β-lactamase 1 (NDM-1)-producing P. aeruginosa in Malaysia maybe travel-associated.
Insights
Three multidrug-resistant Pseudomonas aeruginosa strains producing carbapenem-resistant metallo-β-lactamases (MBLs) were identified in Malaysia. These strains harbored blaIMP-1, blaVIM-2, and blaNDM-1 genes, with blaIMP-1 and blaNDM-1 being novel findings in Malaysia.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Rising carbapenem resistance in Pseudomonas aeruginosa is a global health concern.
- Metallo-β-lactamases (MBLs) are key enzymes conferring carbapenem resistance.
- The prevalence of MBL-producing P. aeruginosa in Malaysia required investigation.
Purpose of the Study:
- To investigate the isolation and characterization of MBL-producing P. aeruginosa clinical strains in Malaysia.
- To identify the specific carbapenemase genes present in these resistant strains.
- To determine the genetic relatedness of the identified MBL-producing isolates.
Main Methods:
- Isolation and identification of 53 P. aeruginosa clinical strains from Malaysia.
- Antimicrobial susceptibility testing and determination of Minimum Inhibitory Concentrations (MICs) for carbapenems.
- Screening for MBL production using phenotypic tests (e.g., IMP-EDTA synergy test, MBL Etest) and genotypic confirmation via PCR for carbapenemase genes.
- Multilocus Sequence Typing (MLST) for molecular typing of isolates.
Main Results:
- Three out of 53 (5.7%) P. aeruginosa strains were identified as MBL producers.
- All three MBL-producing strains exhibited multidrug resistance, with two being resistant to all tested antimicrobials.
- Sequencing confirmed the presence of blaIMP-1, blaVIM-2, and blaNDM-1 genes in individual isolates.
- MLST identified two sequence types: ST235 and ST308.
Conclusions:
- The emergence of IMP-1 and NDM-1 producing P. aeruginosa in Malaysia is reported for the first time.
- These findings highlight the increasing threat of carbapenem-resistant bacteria in the region.
- The presence of these novel MBL genes may be linked to travel-associated transmission.
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