Abstract
Progressive immune damage associated with Human Immunodeficiency Virus (HIV) alters mucosal homeostasis, favouring oral microbial imbalance and the development of opportunistic infections. The aim of this study was to characterize the composition and structure of the oral microbiota in different clinical conditions of HIV infection. A cross-sectional study was conducted in 99 Mexican men divided into five groups: HIV-negative controls, newly diagnosed without antiretroviral treatment, virally suppressed, with oral candidiasis, and with HPV infection. Metagenomic DNA was obtained from salivary samples, and the V1-V3 region of the 16S rRNA gene was massively sequenced. Taxonomic profiles, alpha/beta diversity, differential abundance, microbial co-occurrence networks and degree of dysbiosis were analysed. The results showed distinctive profiles between the groups. Alpha and beta diversity was significantly higher in the groups with oral Candida and HPV lesions, reflecting a disturbance of microbial balance. Differential abundance analysis revealed an increase in Streptococcus, Veillonella, Lactobacillus and Actinomyces genera in HIV patients, while healthy subjects showed higher abundance of Neisseria, Treponema, and Rothia, associated with a eubiotico state. The group of patients with HPV lesions had the highest number of taxa with differential abundance, suggesting an ecological environment altered by the lesion. Analysis of co-occurrence networks revealed a progressive pattern of microbial complexity: controls presented simple networks with weak positive correlations, while HIV groups showed increased connection density and appearance of structured nuclei. The group of patients with HPV lesions presented the highest connectivity, with multiple strongly correlated cores and core nodes such as Prevotella melaninogenica and Shuttleworthia. The dysbiosis score increased progressively from healthy subjects to those with HPV lesions, indicating a gradient of oral microbial disruption. These findings suggest that HIV immunosuppression and the presence of oral lesions are associated with enhanced dysbiosis, although their individual contributions could not be independently assessed due to the absence of non-HIV lesion controls. The integration of microbial networks and dysbiosis scores could be useful for assessing mucosal and immune health in people with HIV and used as biomarkers of clinical progression.