Survival of Gardnerella vaginalis in human urine

The authors studied the survival of Gardnerella vaginalis in human urine and determined conditions for optimum recovery on agar media. Gardnerella counts declined by greater than 99.9% in urine held at 37 degrees C for 24 hours, whereas the falloff was negligible at 4 degrees C. Viability was lost after 6 hours in urine with pH of 5, and only 0.01% cells survived in urine with pH of 7. In contrast, greater than 90% cells survived exposure at pH of 6. Dialysis to remove small molecular weight (less than 14,000) inhibitors did not enhance survival. Co-cultivation with Ureaplasma urealyticum and the addition of glycogen improved survival. Maximum recovery from urine required anaerobic incubation on enriched agar medium (pH 6.5-7.5) for at least 48 hours. Gardnerella vaginalis survives poorly in human urine at 37 degrees C. Culture for these bacteria requires prolonged anaerobic incubation.