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Detection of metallo-beta-lactamase producing Pseudomonas aeruginosa in intensive care units
Arunava Kali1, Sreenivasan Srirangaraj1, Shailesh Kumar1
1Department of Microbiology, Mahatma Gandhi Medical College and Research Institute, Pondicherry, India.
Background:
Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa has emerged as a threat to hospital infection control, due to its multi-drug resistance, especially in intensive care units (ICUs).
Aims:
This study was carried out to detect MBL producing P. aeruginosa isolates from medical and surgical ICUs, to compare and evaluate different phenotypic methods currently in use and to determine antibiograms.
Method:
A prospective study was undertaken to detect MBLs in P. aeruginosa isolates obtained from various clinical samples. A total of 49 strains were recovered from patients admitted in inpatient wards and ICUs, and screened for imipenem resistance by Kirby Bauer disk diffusion method. Detection of MBLs was further done by imipenem-EDTA disk synergy test and combined disk test.
Results:
Out of 49 isolates, 11 isolates (22.4 per cent) were imipenem resistant. All 11 imipenem resistant P. aeruginosa strains, when further tested, were positive for MBL production by combined disk test, but, only eight showed positive results by imipenem-EDTA disk synergy test.
Conclusion:
MBL production was the main resistance mechanism in the 11 carbapenem resistant P. aeruginosa isolates collected, with multidrug resistance associating significantly with MBL production in P. aeruginosa from our institution.
Insights
Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa is a growing threat in intensive care units (ICUs). This study found MBL production to be the primary resistance mechanism in carbapenem-resistant P. aeruginosa isolates.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Science
Background:
- Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa presents a significant challenge for hospital infection control, particularly in intensive care units (ICUs), due to its extensive multi-drug resistance.
- The increasing prevalence of antibiotic resistance in P. aeruginosa necessitates effective detection and management strategies.
Purpose of the Study:
- To detect metallo-beta-lactamase (MBL) producing P. aeruginosa isolates from medical and surgical ICUs.
- To compare and evaluate the efficacy of different phenotypic methods for MBL detection.
- To determine the antibiogram patterns of the isolated P. aeruginosa strains.
Main Methods:
- A prospective study involving the collection of 49 P. aeruginosa strains from clinical samples of patients in inpatient wards and ICUs.
- Screening for imipenem resistance using the Kirby Bauer disk diffusion method.
- Detection of MBLs using the imipenem-EDTA disk synergy test and the combined disk test.
Main Results:
- Out of 49 P. aeruginosa isolates, 11 (22.4%) exhibited resistance to imipenem.
- All 11 imipenem-resistant strains tested positive for MBL production via the combined disk test.
- The imipenem-EDTA disk synergy test identified MBL production in eight of these strains.
Conclusions:
- Metallo-beta-lactamase (MBL) production was identified as the principal mechanism of resistance in the carbapenem-resistant P. aeruginosa isolates.
- A significant association was observed between multidrug resistance and MBL production in P. aeruginosa strains within the studied institution.
