Association of exogenous factors with molecular epidemiology of Staphylococcus aureus in human oral cavity

The frequency of Staphylococcus aureus strains associated with oral cavity microbiota has prodigious consideration. Although S. aureus has been reflected as an ephemeral member of the human oral cavity microbiota, the isolation, identification, and characterization of S. aureus is important. The present study aimed to characterize S. aureus strains from the oral cavity microflora, isolation of S. aureus from the human oral cavity microbiota, and demographic information of the participants to evaluate exogenous factors associated with the presence of S. aureus and their genetic analysis linkage with different factors. The method used in this study is the isolation of oral cavity microbiomes using sheep blood agar and Mannitol salt agar. We performed antibiotic profiling with various antibiotics and genetic analysis utilizing gene-specific primers for specific genes, including nuc, mecA, pvl, agr, and coa. A significant number of S. aureus isolates were found in the oral cavity of humans 18/84 (21.42%), and all 18 strains tested positive for the confirmatory nuc gene. Antibiotic resistance-conferring gene mecA was positive in 10 (55.6%) isolates. It was found that the occurrence of pvl, agr, and coagulase (coa) genes was 9 (50%), 6 (33.33%), and 10 (55.6%), respectively. The genetic analysis reported that significant associations were present between male and mecA gene (P = 0.03) and coa (P = 0.03), smokers with the occurrence of mecA (P = 0.02), agr (P = 0.048) and coa (P = 0.02) genes. Likewise, the association of antibiotic usage was significantly found with mecA (P = 0.02), coa (P = 0.02); however, the individuals who have taken orthodontic treatment recently have a significant association with agr (P = 0.017). The use of mouth rinse was significantly associated with the prevalence of the pvl gene (P = 0.01), and tooth brushing frequency and inflammation of the buccal cavity were also statistically significant in relation to pvl gene prevalence (P = 0.02, 0.00, respectively). Moreover, calories and weight-controlled diet were significantly associated with mecA, agr, and highly significant with coa (P = 0.02, 0.048, 0.000), so all P < 0.05, and no significant association was found between the socioeconomic status of individuals with aforementioned analyzed genes.