Method for isolation of gardnerella vaginalis (Haemophilus vaginalis). Characterization of isolates by gas chromatography.

A method for the isolation of Gardnerella vaginalis (Haemophilus vaginalis) is presented. Bacteria isolated from 48-hour cultures grown on human blood agar were identified by means of beta-hemolysis, colony morphology, sensitivity to antimicrobial agents, oxydase and catalase reactions. Thirty-eight clinical isolates and one test strain were examined for fatty acid composition. Hexadecanoic (16:0), octadecenoic (18:1) and octadecanoic (18:0) were the major fatty acids. Also present, but in minor quantities, were myristic (14:0), hexadecenoic (16:1) and octadecadienoic (18:2) acids. Only insignificant differences between isolates could be detected. No hydroxy fatty acids commonly found in gram-negative bacteria were encountered. Gas chromatographic analysis of G. vaginalis revealed a characteristic and relatively simple pattern. The results support the use of the isolation method, which provides conditions highly selective for G. vaginalis.