Background & objective: Acinetobacter baumannii strains harboring Meallobetalactamases (MBL) pose a significant threat in the context of nosocomial infections. The present investigation was undertaken with the objective of devising a Multiplex PCR methodology for the concurrent detection of MBL genes within A. baumannii strains prevalent in Tehran City, Iran.
Methods: Between October 2020 and February 2021, 100 strains of A. baumannii were procured from burn specimens of hospitalized patients at Motahhari Hospital in Tehran. The identification of A. baumannii strains involved conventional biochemical techniques, coupled with confirmation of the presence of the bla OXA-51 gene. Antibiotic susceptibility was assessed using the Kirby-Bauer disc diffusion test. MBL-producing strains were characterized through a phenotypic approach employing the combined disk test, alongside Multiplex PCR for the simultaneous identification of bla VIM, bla IMP, bla GIM, and bla NDM genes. Statistical analyses were conducted using the chi-square test, with SPSS version 20.0 employed for data processing.
Results: Among 100 strains examined, 96.1% exhibited positivity for MBL, as determined by the combined disk test. The study revealed a predominance of extensively drug-resistant (XDR) strains, with colistin demonstrating the highest level of sensitivity. The genotypic assay unveiled that Multiplex PCR identified bla VIM, bla NDM, and bla IMP in 20 strains, bla VIM and bla NDM in 30 strains, and exclusively the bla NDM gene in 45 strains. Notably, the Multiplex PCR technique exhibited the capacity to concurrently detect MBL genes (bla VIM, bla IMP, bla GIM, bla NDM) in 2 strains.
Conclusion: The current investigation underscores prevalence of the bla NDM gene within clinical strains of A. baumannii. Furthermore, Multiplex PCR emerges as a robust and highly sensitive technique for rapid discernment of the MBL genes within in A. baumannii strains.
Keywords: Acinetobacter baumannii; MBL genes; Multiplex PCR.