Distinct Functional Traits of Lactobacilli from Women with Asymptomatic Bacterial Vaginosis and Normal Microbiota

Abstract

Asymptomatic bacterial vaginosis (BV) in reproductive-age women has serious obstetric and gynecological consequences. Despite its high incidence, the behavior of vaginal lactobacilli in asymptomatic BV is unknown. We analyzed the functional properties of previously isolated vaginal lactobacilli from asymptomatic women with normal, intermediate, and BV microbiota. Lactic acid and antimicrobial activity against seven urogenital pathogens were evaluated from lactobacilli cell-free culture supernatants (CFCs) (n = 207) after 48 h incubation in MRS. Lactobacilli isolates were used to evaluate H2O2, autoaggregation and coaggregation with C. albicans. Lactobacilli from normal microbiota produced more d-lactate than lactobacilli from intermediate and asymptomatic BV (p = 0.007). L. plantarum, L. fermentum and L. reuteri produced greater d-lactate whereas L. rhamnosus, L. crispatus, L. johnsonii were greater producers of l-lactate. Interspecies positive correlation was observed in the lactic acid contents of CFCs. Distribution of H2O2-producing lactobacilli did not vary significantly among the groups. When lactic acid isomers were considered, species from intermediate and BV microbiota clustered together with each other and distinctly from species of normal microbiota. Broad-spectrum antagonism (≥90% inhibition) against E. coli, C. albicans, S. aureus, P. aeruginosa, G. vaginalis, N. gonorrhoeae, S. agalactiae were displayed by 46.86% (97) of isolates. Our study highlights the differential functional properties of vaginal lactobacilli from women with normal microbiota and asymptomatic BV.

Lactobacilli metabolites restore E-cadherin and suppress MMP9 in cervical cancer cells

“…Though all species exerted antiproliferative effect on cervical cells, selective species were more efficient in their cytotoxicity. Our studies including that of others ( Chuah et al, 2019 , Happel et al, 2020 , Pramanick and Aranha, 2020 Dec 9 ) have demonstrated different strains of the same species also vary in their functional properties, hence investigation of several species need to be undertaken to identify the promising probiotic for particular function. Studies have shown that probiotics isolated from different environments or from the same environmental niche have varying functional properties (( Bazireh et al, 2020 , Kahraman et al, 2022 ).…”

“…Interestingly, HPV is implicated in cervical, anal and oropharyngeal cancers ( Schiffman et al, 2016 ). L. salivarius and L. vaginalis are the microbiota commonly identified in the vagina of healthy women and known to play a protective role against urogenital infections ( Madhivanan et al, 2014 , Pino et al, 2019 , Pramanick and Aranha, 2020 Dec 9 ). So it would be interesting to evaluate the indigenous microbiota of healthy individuals for their protective activity against HPV cancers of oral and cervico-vaginal origin.…”

“…The healthy vaginal microenvironment is inhabited by lactobacilli which protect the vagina from reproductive and sexually transmitted infections. These beneficial microbes modify the cervicovaginal ecosystem by the production of antimicrobials, competition with pathogens and improving the epithelial barrier function ( Graver and Wade, 2011 , Spurbeck and Arvidson, 2011 , Pramanick and Aranha, 2020 Dec 9 ). Depletion of these commensals leads to increased infectiousness by various pathogens like Gardnerella vaginalis , Prevotella , Trichomonas vaginalis, Neisseria gonorrhea and Chlamydia trachomatis ( Spurbeck and Arvidson, 2011 , Pramanick et al, 2022 ).…”

“…This cycle of infection could be reversed with the restoration of the normal vaginal flora. However, the effect of lactobacilli has been demonstrated to be strain specific both in vitro ( Pramanick and Aranha, 2020 ) and in vivo ( Guo et al, 2012 ).…”

The impact of pelvic floor electrical stimulation on vaginal microbiota and immunity

“…In particular, the vaginal microbiota dominated by L. crispatus , which produces more lactic acid than L. iners , is thought to be more advantageous for keeping the vagina at a low pH level ( Pramanick and Aranha, 2020 ; Adapen et al., 2022 ; Argentini et al., 2022 ). L. crispatus is related to defense against infections and regulates anti-inflammatory reactions.…”