Distribution of genes related to antimicrobial resistance in different oral environments: a systematic review

The oral cavity is the main source of microorganisms for odontogenic infections. It is important to perform an extensive analysis regarding the reports on the presence of bacteria that carry resistance genes to antimicrobial agents. The aim of the study was to verify the reports on the distribution of genes associated with resistance to antibiotics prescribed in dentistry in different human oral sites.

A systematic review was conducted in electronic databases and gray literature to analyze clinical studies that detected genes of bacterial resistance to antibiotics in saliva, supragingival biofilm, and endodontic infections. Data regarding the research group, geographic location, sample source, number of subjects, methods for sample analysis, the targeted gene groups, and the detection rates were collected. Descriptive data analysis was performed.

Preliminary analysis was performed in 152 titles; 50 abstracts were reviewed, and 29 full texts were obtained. Nine articles matched the inclusion criteria (saliva = 2, supragingival biofilm = 1, and endodontic infections = 6). The presence of 33 different targeted genes was evaluated. The most frequently investigated groups of genes were tetracycline and lactamics (tetM, tetQ, tetW, and cfxA). There was a wide range for the detection rates of each resistance gene among studies and for each specific gene group.

This systematic review highlights the presence of resistance genes to antimicrobial agents in saliva, dental biofilm, and endodontic infections, especially for tetracycline and lactamics. There is a lack of reports on the presence of genes and resulting outcomes obtained through the therapeutic approaches for infection control.