Gardnerella biofilm involves females and males and is transmitted sexually

Abstract

Objective: To study the incidence and distribution of adherent Gardnerella vaginalis.

Methods: Bacteria adherent to desquamated epithelial cells in the urine were detected using fluorescence in situ hybridization (FISH). Urine from patients with bacterial vaginosis (BV, n = 20), their partners (n = 10) and different control populations (n = 344) including pregnant women and their partners, randomly selected populations of hospitalized man, women and children as also healthy controls was investigated.

Results: Gardnerella was found in two different forms: cohesive and dispersed. In the cohesive form, Gardnerella were attached to the epithelial cells in groups of highly concentrated bacteria. In the dispersed form, solitary Gardnerella were intermixed with other bacterial groups. Cohesive Gardnerella was present in all patients with proven BV and their partners, in 7% of men and 13% of women hospitalized for reasons other than BV, in 16% of pregnant women and 12% of their male partners, and in none of the healthy laboratory staff or children. In sexual partners, occurrence of cohesive Gardnerella was clearly linked. Dispersed Gardnerella were found in 10-18% of randomly selected females, 3-4% of males and 10% of children and not sexually linked. In daily longitudinal investigations over 4 weeks no transition between cohesive and dispersed Gardnerella and vice versa was observed. Transmission of a cohesive Gardnerella strain could be followed retrospectively over 15 years using molecular genetic methods.

Conclusions: Cohesive Gardnerella biofilm is a distinct, clearly definable entity which involves both genders and is sexually transmitted. The correct name distinguishing it from symptom-defined conditions like BV should be gardnerellosis and for the bacterium Gardnerella genitalis.