Penile bacteria associated with HIV seroconversion, inflammation, and immune cells

Area of Science:

• Microbiology
• Immunology
• Infectious Diseases

Background:

• The foreskin is a primary site for heterosexual HIV-1 acquisition in uncircumcised men.
• Variability in HIV-1 susceptibility exists among men with similar exposure risks.
• The foreskin microbiome, rich in anaerobic bacteria, is implicated in HIV acquisition.

Purpose of the Study:

• To identify specific anaerobic bacterial species in the foreskin microbiome associated with increased HIV-1 risk.
• To elucidate the mechanisms by which these bacteria influence HIV susceptibility.

Main Methods:

• Analysis of the foreskin microbiome composition.
• Assessment of bacterial effects on cytokine production in foreskin tissue.
• Evaluation of immune cell recruitment to the inner foreskin.

Main Results:

• Six specific anaerobic bacterial species (Peptostreptococcus anaerobius, Prevotella bivia, Prevotella disiens, Dialister propionicifaciens, Dialister micraerophilus, and a Dialister succinatiphilus near-neighbor) were identified.
• These species significantly increased cytokine production and recruited HIV-susceptible CD4+ T cells.
• The presence of these bacteria was associated with HIV acquisition.

Conclusions:

• The penile microbiome, specifically certain anaerobic bacteria, enhances host susceptibility to HIV-1.
• These identified bacterial species are potential targets for novel microbiome-based HIV prevention strategies.