Determination of factors affecting the community structure of Gardnerella spp. in the vaginal microbiome
type: CreativeWork
description: Gardnerella spp. are a hallmark of bacterial vaginosis – a vaginal dysbiosis characterized by the shift from a lactobacilli dominated vaginal microbiome to a diverse microbiome composed of many aerobic and anerobic bacteria. Gardnerella spp. are diverse both phenotypically and genotypically and likely differ in their roles in the pathogenesis of vaginosis. Four cpn60-defined subgroups: A, B, C, and D, corresponding to thirteen “genome species” have been identified. Multiple subgroups of Gardnerella usually colonize vagina simultaneously. Subgroups A and C are the most common and abundant, while subgroup D is rarely abundant. The factors determining Gardnerella community composition and dynamics are unknown. Since the vaginal environment has a limited supply of host-derived nutrients, it is intuitive that species of Gardnerella may interact to secure resources, especially when they dominate the microbiome. The first objective of our study, therefore, was to determine the types of interactions between Gardnerella spp.. While no evidence of contact-independent interaction was identified, evaluation of the outcomes of co-cultures of 2, 3 or 4 isolates indicated that resource-based, scramble competition was prevalent among Gardnerella spp.. Although competition was common, not all Gardnerella subgroups were affected equally by the competition. While A, B, and C were negatively affected, the growth rate of subgroup D isolates increased with increasing numbers of competitors. The success of this rare subgroup and its maintenance in the vaginal microbiome at low abundance might be explained by negative frequency-dependent selection in which the fitness of a species is highest when its relative abundance in a community is low. Species that are nutritional generalists and that occupy distinct niches from their more abundant competitors are candidates for negative frequency-dependent selection. To test this hypothesis, we evaluated the amount of niche overlap between Gardnerel…
abstract: Gardnerella spp. are a hallmark of bacterial vaginosis – a vaginal dysbiosis characterized by the shift from a lactobacilli dominated vaginal microbiome to a diverse microbiome composed of many aerobic and anerobic bacteria. Gardnerella spp. are diverse both phenotypically and genotypically and likely differ in their roles in the pathogenesis of vaginosis. Four cpn60-defined subgroups: A, B, C, and D, corresponding to thirteen “genome species” have been identified. Multiple subgroups of Gardnerella usually colonize vagina simultaneously. Subgroups A and C are the most common and abundant, while subgroup D is rarely abundant. The factors determining Gardnerella community composition and dynamics are unknown. Since the vaginal environment has a limited supply of host-derived nutrients, it is intuitive that species of Gardnerella may interact to secure resources, especially when they dominate the microbiome. The first objective of our study, therefore, was to determine the types of interactions between Gardnerella spp.. While no evidence of contact-independent interaction was identified, evaluation of the outcomes of co-cultures of 2, 3 or 4 isolates indicated that resource-based, scramble competition was prevalent among Gardnerella spp.. Although competition was common, not all Gardnerella subgroups were affected equally by the competition. While A, B, and C were negatively affected, the growth rate of subgroup D isolates increased with increasing numbers of competitors. The success of this rare subgroup and its maintenance in the vaginal microbiome at low abundance might be explained by negative frequency-dependent selection in which the fitness of a species is highest when its relative abundance in a community is low. Species that are nutritional generalists and that occupy distinct niches from their more abundant competitors are candidates for negative frequency-dependent selection. To test this hypothesis, we evaluated the amount of niche overlap between Gardnerel…
author: Khan, Salah Uddin
keywords: Gardnerella, vaginal microbiome, bacterial vaginosis (BV), microbial ecology
date published: 2021-06-01
date modified: 2026-07-24T04:26:54Z
provider: University of Saskatchewan
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Saskatchewan

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10388/13406