Research Article

Waqas Ahmad, Erman Salih İstifli

Published on : June 2024 | Volume : 1 Issue : 1

Abstract :

Among the emerging pathogens, Staphylococcus aureus has ability to secrete virulence factors solely depends upon the Quorum Sensing (QS) system especially Accessory gene regulating (agr) operon. If agr-operon is disrupted, they are no longer virulent to establish the disease. This study aims to understand the disruptions in the agr-operon. A total of 460 complete genomes of S. aureus were downloaded from NCBI and analyzed using ANI and insilico MLST. For downstream analyses, 459 genomes were selected and pangenome was estimated along with core genome phylogeny and recombination identification. It was revealed that these genomes were mainly isolated from humans (n=308) and animals (n=54) while isolation history of 98 genomes was unknown. There was also significant difference in distribution of genomes association with clonal complexes. Pan-genome studies revealed higher percentage of accessory genes as compared to core and unique genes. On the other hand, agr-defects were present in 30 (6.5%) strains of the pangenome. Except agrD, other agr genes i.e. agrA, agrB and agrC were found defective. AgrB defects have not been previously reported. Frame shift mutations or small indels could be major causes of these defects. This could be a possible outcome of genome reduction, facilitating prolonged infection in chronic cases, antibiotic-resistant strains, elderly individuals, and immuno-compromised cases.