Antimicrobial resistance genes in the oral microbiome

This systematic review aimed to map the oral resistome by analyzing clinical studies that detected bacterial antimicrobial resistance genes (ARGs) in the oral cavity using molecular techniques. Out of 580 studies, 15 met the inclusion criteria and identified 159 unique ARGs conferring resistance to 22 antibiotic classes across six regions of the oral cavity. The supragingival biofilm and saliva exhibited the highest richness of ARGs, with 49 ARGs found across all sampled locations. Thirteen studies reported on bacterial species associated with ARGs, with 65 ARG-carrying species identified in NGS studies compared to a mean of 4 species in PCR studies. Comparisons between healthy and diseased states revealed that a healthy oral microbiome harbors a more diverse resistome at the antibiotic class level. The supragingival resistome demonstrated the richest composition in both health and disease, with tetracycline ARGs predominating in the supragingival and saliva resistomes in cases of dental caries.