Restaurant occupational exposure affects the profiles of oral and gut pathobiomes and resistomes

The impact of restaurant occupational exposure, involving contact with food-processing environments, raw materials, and customers, on the differences between oral and gut pathobiomes and resistomes remains poorly understood. A comprehensive metagenomic analysis of paired oral and fecal samples from Front-of-House (FOH) and Back-of-House (BOH) restaurant workers determined that the gut microbiome acts as the primary reservoir, exhibiting greater alpha diversity and a higher burden of pathogens/resistomes (including high-risk Rank_I genes). In contrast, the oral microbiome was more sensitive to occupational differences. Significant beta diversity variations in microbiomes, antimicrobial resistance genes (ARGs), and virulence factors were observed exclusively in oral samples. Notably, Salmonella Typhimurium was significantly more prevalent in the oral cavity of BOH workers (p = 0.047), indicating their potential role as intermediaries in foodborne pathogen transmission. Strain-level analysis confirmed that clonal strains of the opportunistic pathogen and probiotics were shared between the oral cavity and the gut. O2PLS analysis identified plasmids as the main correlates of ARGs. Conclusively, while the gut serves as the primary reservoir for pathogens/resistomes, restaurant occupational exposure distinctly shapes oral microbial/resistome profiles, underscoring the critical need for reinforced hygiene management, particularly for BOH workers, to mitigate pathogen and resistance transmission.