Genome Investigation of Urinary Gardnerella Strains and Their Relationship to Isolates of the Vaginal Microbiota.

Gardnerella is a frequent member of the urogenital microbiota. Given the association between Gardnerella vaginalis and bacterial vaginosis (BV), significant efforts have been focused on characterizing this species in the vaginal microbiota. However, Gardnerella also is a frequent member of the urinary microbiota. In an effort to characterize the bacterial species of the urinary microbiota, we present here 10 genomes of urinary Gardnerella isolates from women with and without lower urinary tract symptoms. These genomes complement those of 22 urinary Gardnerella strains previously isolated and sequenced by our team. We included these genomes in a comparative genome analysis of all publicly available Gardnerella genomes, which include 33 urinary isolates, 78 vaginal isolates, and 2 other isolates. While once this genus was thought to consist of a single species, recent comparative genome analyses have revealed 3 new species and an additional 9 groups within Gardnerella Based upon our analysis, we suggest a new group for the species. We also find that distinction between these Gardnerella species/groups is possible only when considering the core or whole-genome sequence, as neither the sialidase nor vaginolysin genes are sufficient for distinguishing between species/groups despite their clinical importance. In contrast to the vaginal microbiota, we found that only five Gardnerella species/groups have been detected within the lower urinary tract. Although we found no association between a particular Gardnerella species/group(s) and urinary symptoms, further sequencing of urinary Gardnerella isolates is needed for both comprehensive taxonomic characterization and etiological classification of Gardnerella in the urinary tract.IMPORTANCE Prior research into the bacterium Gardnerella vaginalis has largely focused on its association with bacterial vaginosis (BV). However, G. vaginalis is also frequently found within the urinary microbiota of women with and without lower urinary tract symptoms as well as individuals with chronic kidney disease, interstitial cystitis, and BV. This prompted our investigation into Gardnerella from the urinary microbiota and all publicly available Gardnerella genomes from the urogenital tract. Our work suggests that while some Gardnerella species can survive in both the urinary tract and vagina, others likely cannot. This study provides the foundation for future studies of Gardnerella within the urinary tract and its possible contribution to lower urinary tract symptoms.

Infection through structured polymicrobial Gardnerella biofilms (StPM-GB).

BACKGROUND: We analysed data on bacterial vaginosis (BV) contradicting the paradigm of mono-infection. METHODOLOGY: Tissues and epithelial cells of vagina, uterus, fallopian tubes and perianal region were investigated using fluorescence in situ hybridization (FISH) in women with BV and controls. RESULTS: Healthy vagina was free of biofilms. Prolific structured polymicrobial (StPM) Gardnerella-dominated biofilm characterised BV. The intact StPM-Gardnerella-biofilm enveloped desquamated vaginal/prepuce epithelial cells and was secreted with urine and sperma. The disease involved both genders and occurred in pairs. Children born to women with BV were negative. Monotherapy with metronidazole, moxifloxacin or local antiseptics suppressed but often did not eradicate StPM-Gardnerella-biofilms. There was no BV without Gardnerella, but Gardnerella was not BV. Outside of StPM-biofilm, Gardnerella was also found in a subset of children and healthy adults, but was dispersed, temporal and did not transform into StPM-Gardnerella-biofilm. CONCLUSIONS: StPM-Gardnerella-biofilm is an infectious subject. The assembly of single players to StPM-Gardnerella-biofilm is a not trivial every day process, but probably an evolutionary event with a long history of growth, propagation and selection for viability and ability to reshape the environment. The evolutionary memory is cemented in the structural differentiation of StPM-Gardnerella-biofilms and imparts them to resist previous and emerging challenges.