Scientists have identified seven bacterial species whose presence in high concentrations may significantly increase the risk of HIV infection in women. The findings published online in the journal Lancet Infectious Diseases add strength to a growing body of evidence that the make-up of bacterial communities in the vagina -- the vaginal microbiome -- may increase or decrease HIV risk for women depending on which bacteria are there. The results are based on data collected for years by AIDS researchers in six African nations. The research could lead to a better understanding of how biological conditions may promote infection by the