Exploring the pangenome landscape of Mycobacterium avium complex: insights into phylogeny and lifestyle

The Mycobacterium avium complex (MAC) consists of ubiquitously present bacteria causing diseases in humans and animals. MAC infections have led to global outbreaks in recent decades. The ever-increasing MAC infections coupled with antibiotic resistance increased the economic burden on healthcare facilities, underlining the need for novel therapeutic strategies for controlling them. The purpose of the study was to examine the pangenome of MAC, understand the factors shaping the phylogeny and pathogenesis, and recognize the functionalities associated with COGs and KEGG pathways. Pangenome analysis using 90 complete genomes identified 2320 core, 1893 to 3958 accessory genes, and 6644 unique genes. While the open pangenome had an expansion rate “b” of 0.312212, the core genome remained stable. The accessory genes contributed to the variability, shaped adaptations in myriad environments, and facilitated survival within different hosts. Phylogenetic analysis demonstrated the interrelationships and depicted geographical relatedness between the strains. Besides, it reflected the ability to adapt to diverse conditions. Functional assessment of the pangenome components in COGs and KEGG disclosed the role of metabolic activities and pathogenic genes necessary for maintaining the lifestyle of these bacteria. Noteworthy genes in COGs linked to the pathogenesis of MAC included TetR/AcrR/ArC/ArsR/GntR/MerR/MarR family transcriptional regulators, MCE family proteins, Mmpl family proteins, PE/PPE family, and PPE repeat proteins, cytochrome P450, Type—II, and VII secretion system proteins, mycobactin polyketide synthetases, EmrB/QacA subfamily proteins, and virulence factor mvin family domain proteins. This study highlighted better comprehension of MAC and laid the foundation for future investigations to expand the outcomes.