Longitudinal Assessment of Pigtailed Macaque Lower Genital Tract Microbiota by Pyrosequencing Reveals Dissimilarity to the Genital Microbiota of Healthy Humans

Vaginal bacterial communities play an important role in human health and have been shown to influence HIV infection. Pigtailed macaques (Macaca nemestrina) are used as an animal model of HIV vaginal infection of women. Since the bacterial microbiota could influence retrovirus infection of pigtailed macaques, the genital microbiota in 10 cycling macaques was determined by pyrosequencing. The microbiota of all macaques was polymicrobial with a median of 13 distinct genera. Strikingly, the genera Sneathia and Fusobacterium, both in the phylum Fusobacteria, accounted for 18.9% and 13.3% of sequences while the next most frequent were Prevotella (5.6%), Porphyromonas (4.1%), Atopobium (3.6%), and Parvimonas (2.6%). Sequences corresponding to Lactobacillus comprised only 2.2% of sequences on average and were essentially all L. amylovorus. Longitudinal sampling of the 10 macaques over an 8-week period, which spanned at least one full ovulatory cycle, showed a generally stable presence of the major types of bacteria with some exceptions. These studies show that the microbiota of the pigtailed macaques is substantially dissimilar to that found in most healthy humans, where the genital microbiota is usually dominated by Lactobacillus sp. The polymicrobial makeup of the macaque bacterial populations, the paucity of lactobacilli, and the specific types of bacteria present suggest that the pigtailed macaque microbiota could influence vaginal retrovirus infection.