Interplay Between Oral Microbiota and Mouth Health in People Living With HIV Under Antiretroviral Therapy With or Without Periodontitis

People living with HIV (PLWH) in combined antiretroviral therapy (cART) face microbiota shifts linked to immune status, ART regimen, and periodontal diseases, which are capable of inducing local and systemic inflammation. This study aimed to analyze the oral microbial community composition in PLWH under cART with ( n = 24) or without ( n = 25) periodontitis using shotgun metagenomic sequence analysis, and describe the interaction between bacterial species, clinical and immunological parameters, and the response to nonsurgical periodontal therapy (NSPT). Saliva samples were collected at baseline for both groups, and 30 days after NSPT for the periodontitis group. Within the periodontitis group, all periodontal parameters presented highly significant improvement after NSPT when compared to baseline. The gingival microbiota did not differ significantly between patients with periodontitis and controls; however, a wider range of bacterial species was found in the microbiota of the periodontitis group compared to the control group, while post‐treatment the periodontitis group presented an alpha diversity intermediate between the two former groups. Regarding the distribution of the different bacterial species, Porphyromonas gingivalis was found significantly enriched in the periodontitis group, along with different Treponema sp., Fretibacterium fastidiosum , Campylobacter rectus , Bacteroides zoogleoformans , Tannerella forsythia , and Porphyromonas endodontalis . Correlations between seven inflammatory markers and seven periodontitis‐related bacterial taxa were found for saliva in the group of periodontitis patients, which was not the case in controls; interestingly, the profiles after NSPT showed intermediate results. By contrast to saliva, the inflammatory markers of periodontitis patients showed no marked differences in blood plasma, except for TNF‐alpha and partly IL‐4. In view of the fact that oral microbial imbalance may contribute not only to local disease but also to systemic immune activation in the course of HIV‐1 infection, reinforcing the importance of maintaining periodontal health represents a part not to be neglected for an optimal management of PLWH.