The influence of breast milk microbiota from HIV-infected women on infant gut microbiota colonization within the first two weeks of life

This study is among the first to investigate breast milk microbiota in the context of HIV infection in Zimbabwe. We demonstrated that maternal HIV infection and cotrimoxazole prophylaxis did not measurably alter breast milk or early infant gut microbiota composition. Despite limited statistical power to detect small-to-moderate effects, taxa-level correlations and microbial source tracking supported breast milk as a major contributor to early gut colonization. These results underscore breast milk-mediated microbial seeding in early life, while highlighting the need for larger longitudinal studies to define how maternal HIV status may subtly influence vertical microbial transfer.