Correlation Between Enzymatic and Non-Enzymatic Genes in Acinetobacter baumannii Isolates
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Background
Acinetobacter baumannii is a multidrug-resistant bacterium responsible for severe infections, particularly in hospital settings. Its resistance is driven by enzymatic genes such as those encoding beta-lactamases and carbapenemases, which degrade antibiotics, and non-enzymatic genes that modify mechanisms like efflux pumps and membrane permeability, further enhancing its defence against treatments. Together, these factors allow A. baumannii to thrive in clinical environments, complicating infection management.
Objective
This study aimed to explore the relationships between beta-lactamases, carbapenemases, efflux pumps, and membrane permeability changes, to understand their collective contribution to A. baumannii’s multidrug resistance.
Materials and Methods
Among 300 clinical isolates from urine, blood, wounds, and burns, 25 (8.33%) were identified as A. baumannii . These included 8% from urine, 12% from blood, and 40% each from wound and burn swabs. all specimens were taken from patients who have different symptoms in hospital of Al-Hilla Teaching Hospital/ Babylon. The research was carried out through the period January and June 2024. Bacterial identification was conducted using the VITEK-2 system and HI-Chromoagar® A. baumannii . Enzymatic genes were detected using conventional PCR, while non-enzymatic genes were analyzed via RT-qPCR.
Results
Molecular analysis revealed the presence of beta-lactamase (blaOXA-51, blaOXA-23) and metallo-beta-lactamase genes (blaVIM, blaIMP), with high antibiotic resistance rates. Gene expression analysis highlighted efflux pump upregulation (adeB) and altered permeability (CarO), reinforcing multidrug resistance mechanisms.
Conclusion
The combined action of enzymatic and non-enzymatic resistance genes in A. baumannii presents a significant treatment challenge, necessitating multi-target therapeutic approaches.
