Evaluation of the Efficacy of Selected Compounds in Inhibiting Bacterial Conjugation and Transfer of the Antimicrobial Resistance Plasmids

Authors

• Sundus Q. Mohammed, Department of Biology, College of Science, Mustansiriyah University, Baghdad, IraqFollow
• Mohammed F. Al-Marjani, Department of Microbiology, College of Science, Mustansiriyah University, Baghdad, IraqFollow
• Nadheema H. Hussein, Department of Biology, College of Science, Mustansiriyah University, Baghdad, IraqFollow

Abstract

This study aimed to investigate the dynamic changes in antimicrobial resistance, including multidrug-resistant strains as well as the transfer of carbapenemase genes, and to determine the role of plasmids in the transfer of such characteristics in the presence of selected compounds. A total of 115 Klebsiella pneumoniae isolates were collected from patients in five hospitals in Baghdad, Iraq, between October 2024 and January 2025. The disk diffusion method was used to determine antimicrobial susceptibility, and the modified carbapenem inactivation methods were used to detect phenotypic carbapenemase production. Molecular detection of carbapenemase genes was performed by polymerase chain reaction (PCR). Conjugation assays were conducted to assess plasmid transfer, followed by conjugation inhibition experiments using a range of compounds and different pH values. Plasmid DNA profiles were analyzed using agarose gel electrophoresis. Among the isolates, 52.17% (60/115) were identified as carbapenem-resistant and exhibited high levels of resistance to multiple antibiotic classes. The bla_NDM and bla_OXA-48 genes were detected among the carbapenem-resistant isolates, whereas the bla_IMP gene was not detected. Plasmid transfer occurred at a frequency of 1.3× 10^-2. Conjugation was inhibited by indole, capsaicin, amoxicillin, and acidic pH, whereas it was enhanced by bile salts, sweeteners, inulin, pomegranate peel extract, salicylic acid, and alkaline pH. These findings demonstrate that plasmids and environmental factors play critical roles in the dissemination of carbapenem resistance, highlighting that certain compounds can promote or inhibit horizontal gene transfer in bacteria.

Keywords

Antimicrobial resistance, Carbapenemase genes, Carbapenem resistance, Horizontal gene transfer, Plasmid conjugation

Subject Area

Biology

Article Type

Article

First Page

3486

Last Page

3501

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

How to Cite this Article

Mohammed, Sundus Q.; Al-Marjani, Mohammed F.; and Hussein, Nadheema H. (2026) "Evaluation of the Efficacy of Selected Compounds in Inhibiting Bacterial Conjugation and Transfer of the Antimicrobial Resistance Plasmids," Baghdad Science Journal: Vol. 23: Iss. 10, Article 5.
DOI: https://doi.org/10.21123/2411-7986.5426