Comparison of Lactobacillus crispatus isolates from Lactobacillus-dominated vaginal microbiomes with isolates from microbiomes containing bacterial vaginosis-associated bacteria

Abstract

Vaginal lactobacilli can inhibit colonization by and growth of other bacteria, thereby preventing development of bacterial vaginosis (BV). Amongst the lactobacilli, Lactobacillus crispatus appears to be particularly effective at inhibiting growth of BV-associated bacteria. Nonetheless, some women who are colonized with this species can still develop clinical BV. Therefore, we sought to determine whether strains of L. crispatus that colonize women with lactobacillidominated vaginal microbiomes are distinct from strains that colonize women who develop BV. The genomes of L. crispatus isolates from four women with lactobacilli-dominated vaginal microbiomes (,1 % 16S rRNA reads above threshold from genera other than Lactobacillus) and four women with microbiomes containing BV-associated bacteria (.12 % 16S rRNA reads from bacterial taxa associated with BV) were sequenced and compared. Lactic acid production by the different strains was quantified. Phage induction in the strains was also analysed. There was considerable genetic diversity between strains, and several genes were exclusive to either the strains from Lactobacillus-dominated microbiomes or those containing BV-associated bacteria. Overall, strains from microbiomes dominated by lactobacilli did not differ from strains from microbiomes containing BV-associated bacteria with respect to lactic acid production. All of the strains contained multiple phage, but there was no clear distinction between the presence or absence of BV-associated bacteria with respect to phage-induced lysis. Genes found to be exclusive to the Lactobacillus-dominated versus BV-associated bacteria-containing microbiomes could play a role in the maintenance of vaginal health and the development of BV, respectively.

Biological properties and production of bacteriocins‐like‐inhibitory substances by Lactobacillus sp. strains from human vagina

“…Lactobacillus crispatus and L. gasseri produce various compounds that are potent inhibitors of BV‐associated bacterial species, and for this reason, women who have these species in vagina are less likely to develop BV (Abdelmaksoud et al . ). Lactobacillus fermentum and L. gasseri are species very resistant to low pH and excellent biofilm producers (Fuochi et al .…”

“…The taxonomic classification of the isolated lactobacilli confirms the reported dominance of L. crispatus and L. gasseri in a healthy vagina (Antonio et al 2005;Martin et al 2008). Lactobacillus crispatus and L. gasseri produce various compounds that are potent inhibitors of BV-associated bacterial species, and for this reason, women who have these species in vagina are less likely to develop BV (Abdelmaksoud et al 2016). Lactobacillus fermentum and L. gasseri are species very resistant to low pH and excellent biofilm producers (Fuochi et al 2015(Fuochi et al , 2017c, important characteristics to inhibit most responsible bacteria for AV and Candida sp.…”

The vaginal microbiota, human papillomavirus infection and cervical intraepithelial neoplasia: what do we know and where are we going next?

“…The remaining genome diversity gives rise to the existence of different strains, which may have different functional genes that induce different biological properties. Further evidence is required in order to determine whether only certain strains of a particular bacterial species are either protective or pathogenic with regards to HPV and cervical dysplasia, and a recent study by Abdelmaksoud and colleagues [140] hints this is very likely. The team compared strains of L. crispatus that colonised women with, and without BV, demonstrated considerable genomic diversity within the species and identified several genes exclusive to the presence or absence of BV [140].…”

“…Further evidence is required in order to determine whether only certain strains of a particular bacterial species are either protective or pathogenic with regards to HPV and cervical dysplasia, and a recent study by Abdelmaksoud and colleagues [140] hints this is very likely. The team compared strains of L. crispatus that colonised women with, and without BV, demonstrated considerable genomic diversity within the species and identified several genes exclusive to the presence or absence of BV [140]. These genes require further investigation to help understand the protective mechanisms exploited by certain bacteria, and other disease-associated species should also be studies using metagenomic techniques, which in turn will support development of appropriate probiotic preparations.…”

The genital tract and rectal microbiomes: their role in HIV susceptibility and prevention in women

“…Sneathia spp., BVAB1, BVAB2, and likely others), and such omissions can have dramatic effects in skewing abundance profiles and misclassifying samples to CSTs, especially in samples where such bacterial taxa may be dominant. In this regard, whole‐genome sequencing and comparative genomics of vaginal bacterial isolates could advance the accurate assessment of the vaginal microbial community structure and function, as has been undertaken for select vaginal isolates . One of the greatest strengths of SMS is the gene‐ and function‐level information it provides on the microbiome.…”