Associations of cocaine use and HIV infection with the intestinal microbiota, microbial translocation, and inflammation.

Objective: HIV and illicit drug use have been associated with altered nutrition, immune function, and metabolism. We hypothesized that altered composition and decreased diversity of the intestinal microbiota, along with microbial translocation, contribute to nutritional compromise in HIV-infected drug users.

Method: We enrolled 26 men and 6 women, 15 HIV infected and 17 HIV uninfected, in this exploratory, cross-sectional study; 7 HIV-infected and 7 HIV-uninfected participants had used cocaine within the previous month. We examined the independent effects of cocaine use and HIV infection on the composition and diversity of the intestinal microbiota, determined by 16S rRNA gene pyrosequencing. Using dietary records, anthropometrics, and dual x-ray absorptiometry, we examined the additional effects of nutritional indices on the intestinal microbiota. We compared markers of inflammation and microbial translocation between groups.

Results: Cocaine users had a higher relative abundance of Bacteroidetes (M ± SD = 57.0% ± 21 vs. 37.1% ± 23, p = .02) than nonusers. HIV-infected individuals had a higher relative abundance of Proteobacteria (Mdn [interquartile range] = 1.56% [0.5, 2.2] vs. 0.36% [0.2, 0.7], p = .03), higher levels of soluble CD14 and tumor necrosis factor-α, and lower levels of anti-endotoxin core antibodies than uninfected subjects. HIV-infected cocaine users had higher interferon-γ levels than all other groups. Food insecurity was higher in HIV-infected cocaine users.

Conclusions: We identified differences in the relative abundance of major phyla of the intestinal microbiota, as well as markers of inflammation and microbial translocation, based on cocaine use and HIV infection. Nutritional factors, including alcohol use and lean body mass, may contribute to these differences.