Biotypes of Gardnerella vaginalis.

A simple and reproducible scheme for identifying biotypes of Gardnerella vaginalis has been developed, based on reactions for lipase, hippurate hydrolysis, and beta-galactosidase. Among a total of 359 strains tested, eight biotypes were observed, the most common ones being types 1 (beta-galactosidase positive, lipase positive, hippurate positive), 2 (beta-galactosidase negative, lipase positive, hippurate positive), and 5 (beta-galactosidase negative, lipase negative, hippurate positive). The distribution in biotypes was similar among isolates from Antwerp, Seattle, and Nairobi. There were no differences in biotypes between strains isolated from patients with and without bacterial vaginosis (nonspecific vaginitis). Up to 14% of women with bacterial vaginosis harbored at least two different biotypes of G. vaginalis in the vagina. G. vaginalis strains isolated before and after treatment for bacterial vaginosis belonged to identical biotypes when the time interval between two specimens was less than 1 week. Similarly, G. vaginalis isolates from the vaginas of women with bacterial vaginosis and from the urethras of their male sex partners belonged to identical biotypes when strains were isolated within the same 24-h period from both partners (P less than 0.005).