Characterisation of probiotic properties in human vaginal lactobacilli strains

Abstract

BackgroundVaginal lactobacilli offer protection against recurrent urinary infections, bacterial vaginosis, and vaginal candidiasis.ObjectiveTo characterise the isolated vaginal lactobacilli strains for their probiotic properties and to compare their probiotic potential.MethodsThe Lactobacillus strains were isolated from vaginal samples by conventional culturing and identified by sequencing of the 16S rDNA fragment. Several functional properties were detected (production of hydrogen peroxide and lactic acid; antagonistic activity against Escherichia coli, Candida albicans, Candida glabrata, and Gardnerella vaginalis; auto-aggregation and adhesiveness) as well as safety (haemolytic activity, antibiotic susceptibility, presence of transferrable resistance genes).ResultsA total of 135 vaginal lactobacilli strains of three species, Lactobacillus crispatus (56%), Lactobacillus jensenii (26%), and Lactobacillus gasseri (18%) were characterised using several functional and safety tests. Most of L. crispatus (89%) and L. jensenii (86%) strains produced H2O2. The best lactic acid producers were L. gasseri (18.2±2.2 mg/ml) compared to L. crispatus (15.6±2.8 mg/ml) and L. jensenii (11.6±2.6 mg/ml) (p<0.0001; p<0.0001, respectively). L. crispatus strains showed significantly higher anti-E. coli activity compared to L. jensenii. L. gasseri strains expressed significantly lower anticandidal activity compared to L. crispatus and L. jensenii (p<0.0001). There was no significant difference between the species in antagonistic activity against G. vaginalis. Nearly a third of the strains were able to auto-aggregate while all the tested strains showed a good ability to adhere to HeLa cells. None of the tested lactobacilli caused haemolysis. Although phenotypical resistance was not found to ampicillin, chloramphenicol, erythromycin, gentamycin, tetracycline, and vancomycin, the erm(B), tet(M), and tet(K) were detected in some strains. All strains were resistant to metronidazole, trimethoprim/sulfamethoxazole, and kanamycin.ConclusionsOur study revealed that the production of different antimicrobial metabolites is highly strain-specific and that the metabolites are not correlated with each other. L. crispatus displays better antagonistic activity against E. coli and Candida spp. than L. gasseri and L. jensenii; therefore; a potential probiotic candidate could be found among L. crispatus strains.

Antimicrobial Compounds Produced by Vaginal Lactobacillus crispatus Are Able to Strongly Inhibit Candida albicans Growth, Hyphal Formation and Regulate Virulence-related Gene Expressions

“…Anyhow, our data suggests that the tested Lactobacillus strains had moderate to strong anti- Candida activities with inter-strain variations. Our results are consistent with some previous studies showing that several strains of lactobacilli were effective at inhibiting the growth of C. albicans (Parolin et al, 2015; Hütt et al, 2016). …”

Galacto-oligosaccharides modulate the juvenile gut microbiome and innate immunity to improve broiler chicken performance

“…The administration of L. johnsonii FI9785 to broiler chickens has also been reported to reduce colonization by Clostridium perfringens, E. coli O78:K80 and Campylobacter jejuni that have a significant impact on poultry production (52,53). Lactobacillus crispatus is also a recognized probiotic, but better known for its activity against recurrent urinary infections, bacterial vaginosis, and vaginal candidiasis (54). However, it should be noted that L. crispatus is commonly reported as a major constituent of the chicken microbiome (43,52).…”

Cross sectional analysis of vaginal Lactobacillus in asymptomatic women of reproductive age in Mumbai, India

“…RAPD analysis of Lactobacillus isolates showed considerable genetic diversity among the species. It is well recognized that different isolates of same Lactobacillus species exhibit variable functional properties depending on their strain [33,34], hence it is (185)(186)(187)(188)(189)191,192) were identified by the change in color of media from purple to yellow. Isolate no.…”