Different strains of a bacterium known as a determinant of vaginal health show a variety of colonising abilities and may offer a wider range of options for potential antimicrobial therapy.

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The study of Lactobacillus crispatus strains is outlined in a study by scientists of the Laboratory of Probiogenomics at the MIcrobiome Research Hub in the University of Parma, ‘The core genome evolution of Lactobacillus crispatus as a driving force for niche competition in the human vaginal tract’, which has been accepted for Microbial Biotechnology, an Applied Microbiology International publication.

Vaginal microbiome

The vaginal microbiome is typically manifested by a low degree of biodiversity and is commonly dominated by members of the Lactobacillus genus, such as Lactobacillus inersLactobacillus gasseriLactobacillus jensenii and Lactobacillus crispatus, explained corresponding author Dr Marco Ventura.

“This latter is regarded as the primary determinant of vaginal health. Indeed, in healthy cervicovaginal microbiota, L. crispatus species prevails, producing D- and L-lactic acid, hydrogen peroxide, and bacteriocins, which prevent the overgrowth of possible pathogens, hence preventing upper genital tract infections in the host,” he said. 

“For these reasons, probiotic supplements based on L. crispatus are widely used as vehicles of health-promoting strains in the vaginal environment.”

Genomic analyses

The team carried out genomic sequence-based analyses of 41 novel human-derived L. crispatus isolates along with 200 publicly available genome sequences, allowing them to explore the genetic diversity within the L. crispatus taxon and specifically to dissect the genetic basis supporting their successful colonization of the human vaginal tract. 

Ventura's lab

Staff involved in the study.

“Our findings revealed inter-strain genotypic variation and phenotypic differences between L. crispatus strains, highlighting distinct evolutionary developments that may provide this species with differential abilities to long persist and predominate in the human vaginal tract,” Dr Ventura said.

Colonisation abilities

“This study provides clear insights into the different colonisation abilities of L. crispatus strains of the vaginal tract. Considering the growing scientific evidence about the importance of L. crispatus in preserving/driving the climax of the vaginal tract, this article is relevant for unravelling strain-specific capabilities to successfully dominate the female reproductive tract and, ultimately, selecting suitable L. crispatus strains that could be applied for novel bacterial therapy strategies.

“Future work needs to be carried out in order to validate the here-achieved data in an in vivo model especially involving vaginal pathogens. Such trials will be crucial to better delineate if the here-identified genetic traits supporting a successful colonization of L. crispatus in the human vaginal tract will be also valuable to counteract bacterial infections in the female reproductive tract.”

Microbiome research

This work was performed at the Interdepartmental Centre ‘Microbiome Research Hub’, University of Parma. The MRH is focused on enabling and connecting an interdisciplinary network of scientists and leveraging the most advanced technologies to rapidly realize the biomedical potential of the microbes that live within and upon us. 

The microbiome has a fundamental and continuous impact on with the capacity to promote health or to cause disease. The MRH aims to deliver innovative research that establishes Italy as a center of excellence in human health, to help the development of industry and to attract multinational companies to Italy to start collaborative research.

’The core genome evolution of Lactobacillus crispatus as a driving force for niche competition in the human vaginal tract’ is published in Microbial Biotechnology.