The Vaginal Microbiota in Pig-Tailed Macaques and Colonization with Neisseria gonorrhoeae

Pig-tailed macaques ( Macaca nemestrina ) may serve as a useful animal model of Neisseria gonorrhoeae (GC) infection, but no such models are currently available. To aid in the development of a macaque model of gonorrhea, we characterized the macaque vaginal microbiota and evaluated the effect of streptomycin treatment on GC colonization.

Six female pig-tailed macaques were observed for 96 days, with cervicovaginal samples collected every 2 to 3 days. Samples were taken for 1 month before streptomycin treatment to characterize the vaginal microbiota using 16S rRNA gene sequencing over a menstrual cycle. The animals were treated intramuscularly with streptomycin for 22 days. They were challenged twice, with a 2-week interval, with endocervical GC and once after cessation of antibiotics. GC colonization was assessed via 16S rRNA gene sequencing, nucleic acid amplification tests, and culture.

The macaque vaginal microbiota was diverse and heterogeneous, with several anaerobes typically noted in the human vagina, including Fannyhessea vaginae , Amygdalobacter indicium , and Parvimonas micra . Streptomycin treatment resulted in changes in the diversity and composition of the microbiota, but prolonged GC colonization was not achieved in any animal. Changes in the microbiota were noted during menses.

Alternative approaches are needed to facilitate the establishment of GC infection in pig-tailed macaques.