Study of the Genotypic and Phylogenetic Tree for Acinetobacter baumannii Isolated from Wounds and Burns Patients

Background: Acinetobacter baumannii is a species of bacteria commonly found in soil, water, and various environments. It’s well known as a nosocomial pathogen. Its clinical significance has increased due to its ability to form biofilms, and being multi-drug resistant. Objectives: The study aimed to identify the phylogenetic positioning for A. baumannii and investigate the impact of the genetic variations of the blaOXA gene on the native 3D structure of beta-lactamase and its binding with the host receptor. Methods: One specific PCR fragment partially covering the blaOXA sequences of A. baumannii was selected in this study. Based on the genetic variants of this locus, the patterns of bacterial genetic diversity were assessed. The amplified fragments were exposed to direct sequencing experiments to assess the pattern of genetic polymorphism in the collected bacterial samples. Results: The conducted sequencing reactions indicated the accurate identity of the investigated samples, which were confirmed to be attributed to A. baumannii. The alignment of nucleic acid sequences of the S1 – S4 samples with the most homologous reference sequences of A. baumannii (GenBank acc. no. MK105961.1) revealed the presence of ten nucleic acid variants (31C>T, 72T>C, 129A>G, 141T>G, 206T>G, and 243A>G in S3 and S4, 52G>A and 204T>G in S1, 188T>C in S2, and 93G>A in S1, S3, and S4) that were not available in this reference sequences. The translation of these variants showed that four variants (52G>A, 141T>G, 188T>C, and 206T>G) exhibited four missense impacts (p.117Asp>Asn, p.146Asn>Lys, p.162Val>Ala, and p.168Val>Gly) on the blaOXA encoded enzyme. Conclusion: The study suggests that identified mutations might affect the protein's ability to carry out its biological functions of resisting beta-lactam antibiotics, potentially leading to functional consequences for the survival of the bacteria.