Evaluation of the antibacterial activity of recombinant protein oncorhyncin II against Acinetobacter baumannii (ATCC19606) under in vitro conditions

Abstract

Background and Aim: Multi-drug resistant (MDR) Acinetobacter baumannii is a prevalent hospital pathogen. Antimicrobial peptides (AMPs), such as Oncorhyncin II, have been proposed for treating MDR pathogens. This study aimed to assess the antibacterial activity of recombinant protein Oncorhyncin II against Acinetobacter baumannii (ATCC19606) under in vitro conditions. Methods: In this experimental study, the gene construct pET32a-oncorhyncin II was transferred to Escherichia coli BL21 (DE3) for expressing the recombinant Oncorhyncin II protein. Purification was optimized using nickel affinity chromatography (Ni-NTA), and the peptide's efficacy was evaluated by determining the minimum inhibitory concentration (MIC), bactericidal kinetics, and growth kinetics against Acinetobacter baumannii (ATCC19606). Results: The recombinant Oncorhyncin II protein was successfully expressed in E. coli BL21 (DE3) and purified with over 70% purity. The MIC assay confirmed effective antibacterial activity of Oncorhyncin II against Acinetobacter baumannii at a concentration of 95.87 μg/ml. At 2x MIC, Oncorhyncin II led to a rapid reduction in viable cell count and decreased turbidity of the bacterial inoculum in bactericidal and growth kinetics assessments. Conclusion: The produced recombinant Oncorhyncin II exhibited potent antibacterial activity against Acinetobacter baumannii. These findings can contribute to the development and production of novel antimicrobial drugs for treating infections caused by Acinetobacter baumannii.

Keywords

• antimicrobial peptides
• recombinant proteins
• acinetobacter baumannii