A study to detect Gardnerella vaginalis DNA in interstitial cystitis.

To investigate the possible role of Gardnerella vaginalis in interstitial cystitis (IC), using molecular methods to avoid difficulties with the culture and recovery of viable organisms, and the problems associated with the recovery of low numbers of culturable organisms. Thirty-three bladder biopsy samples (29 paraffin-embedded and four freshly frozen) from patients with IC, diagnosed according to National Institute of Diabetes, Digestive and Kidney Diseases criteria, were assessed. Biopsy samples were used as urine samples may be contaminated by normal vaginal flora. A positive control comprised a 'normal' biopsy sample from a patient with a previous bladder tumour, seeded with G. vaginalis NCTC 10915. Microbial DNA was extracted from all paraffin-embedded and fresh specimens, and subjected to in vitro amplification by polymerase chain reaction (PCR) with G. vaginalis-specific primers. The anticipated PCR product of 333 base pairs was obtained with the positive control, whereas none of the other biopsy samples showed positive amplification specific for G. vaginalis. As there was no G. vaginalis DNA in any of the samples from patients with IC, it is an unlikely candidate in the pathogenesis of IC.