Intensification in Genetic Information and Acquisition of Resistant Genes in Genome of Acinetobacter baumannii: A Pan-Genomic Analysis

Acinetobacter baumannii (A. baumannii) attributes 26% of the mortality rate in hospitalized patients, and the percentage can rise to 46 in patients admitted to ICU as it is a major cause of ventilator-associated pneumonia. It has been nominated as the critical priority organism by WHO for which new therapeutic drugs are urgently required. To understand the genomic identification of different strains, antimicrobial resistance patterns, and epidemiological typing of organisms, whole-genome sequencing (WGS) analysis provides insight to explore new epitopes to develop new drugs against the organism. Therefore, the study is aimed at investigating the whole genome sequence of A. baumannii strains to report the new intensifications in its genomic profile. The genome sequences were retrieved from the NCBI database system. Pan-genome BPGA (Bacterial Pan-genome Analysis Tool) was used to analyze the core, pan, and species-specific genome analysis. The pan and core genome curves were extrapolated using the empirical power law equation f(x) = a.xb and the exponential equation f1(x) = c.e (d.x). To identify the resistant genes with resistant mutations against antibiotics, ResFinder and Galaxy Community hub bioinformatics tools were used. According to pan-genome analysis, there were 2227 core genes present in each species of the A. baumannii genome. Furthermore, the number of accessory genes ranged from 1182 to 1460, and the unique genes in the genome were 931. There were 325 exclusively absent genes in the genome of Acinetobacter baumannii. The pan-genome analysis showed that there is a 5-fold increase in the genome of A. baumannii in 5 years, and the genome is still open. There is the addition of multiple unique genes; among them, genes participating in the function of information and processing are increased.