THE VAGINAL MICROBIOME AND HUMAN PAPILLOMAVIRUS INFECTION: FROM LACTOBACILLARY PROTECTION TO DYSBIOSIS AND THERAPEUTIC PROSPECTS. A NARRATIVE REVIEW
Keywords:
vaginal microbiome, human papillomavirus, Lactobacillus species, dysbiosis, probioticsAbstract
The vaginal microbiome has emerged as an important cofactor in the natural history of human papillomavirus infection and cervical carcinogenesis. Under physiological conditions, the vaginal environment is dominated by a small number of Lactobacillus species that maintain a low pH through lactic-acid production and restrain potential pathogens. Loss of this lactobacillary dominance, a state known as dysbiosis, has been associated with the acquisition, persistence and progression of human papillomavirus infection. This narrative review summarises the current understanding of this relationship across four themes: the protective mechanisms of lactobacilli, the features of dysbiosis and its association with infection, the proposed mechanisms linking dysbiosis and infection and the emerging therapeutic prospects. The evidence consistently shows that a lactobacilli-dominated state is more frequent in uninfected women, whereas a community rich in anaerobes such as Gardnerella vaginalis, Prevotella, Atopobium and Sneathia predominates among the infected. The direction of causation remains unresolved, since dysbiosis may facilitate viral acquisition while the virus may itself reshape the microbiome, a bidirectional, self-reinforcing relationship is increasingly favoured. The species Lactobacillus iners occupies an ambiguous position, being associated with both health and transitional states. Therapeutic restoration of a lactobacilli-dominated community, through probiotics and, more recently, vaginal microbiota transplantation, represents a promising but still preliminary approach for supporting viral clearanceIt is recommended that microbiome assessment, including by targeted molecular assays suitable for routine laboratories, be evaluated for use alongside existing cervical screening and risk-stratification methods, and that microbiome-directed interventions be examined in controlled studies. The literature was identified through searches of PubMed and Google Scholar and was limited to peer-reviewed, indexed journals. This review is intended to provide an integrated synthesis for clinicians and laboratory specialists in the region
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