Bacteriocin production and gene sequencing analysis from vaginal Lactobacillus strains

Abstract

The human vagina is a complex and dynamic ecosystem containing an abundance of microorganisms. In women of childbearing age, this system is dominated by Lactobacillus spp. In the present work, seventeen newly isolated vaginal strains were identified by 16S rDNA sequencing and were investigated for their antimicrobial properties. Twelve of the isolated Lactobacillus strains showed activity against one or more microorganisms. Six and five of them produced substances that inhibited the growth of two different Klebsiella strains and Staphylococcus aureus, respectively. Two lactobacilli strains were active against an Escherichia coli strain, one isolate was active against an Enterococus faecalis strain and another lactobacilli strain showed antimicrobial activity against a Candida parapsilosis strain. The nature of the active compounds was additionally studied, and the presence of bacteriocin-like substances was proved. The genes related to the bacteriocin production in three of the newly isolated strains were identified and sequenced. The presence of gassericin A operon in the genome of the species Lactobacillus crispatus was described for the first time. The presence of antimicrobial activity contributes to their possible use as potential probiotic strains after further research.

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

“…Some vaginal lactobacilli secrete bacteriocins, which also prevent growth of other bacterial species and help to prevent BV (Sabia et al, 2014;Stoyancheva et al, 2014). All of the strains characterized in this study encoded multiple bacteriocins, but the number and type of bacteriocins did not correlate with the level of BV-associated bacteria in the microbiome.…”

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

“…Vaginal Lactobacillus spp. prevent colonisation of bacterial vaginosis-associated bacterial species through maintenance of a low pH [60–63] and bacteriocin production [64–66]. This is important for maintenance of the cervical epithelial barrier function that inhibits entry of HPV to the basal keratinocytes [67].…”

“…Besides influencing pH, as discussed above, species that are protective may inhibit pathogen growth through expression of bacteriocidal and bacteriostatic proteins such as bacteriocins [64] which are through to have evolved as a result of ecosystem competition. Gasserin is an example of such a bacteriocin with Gram-negative and -positive activity that was first isolated from L. gasseri but has since been found to be produced by other strains of L. crispatus and L. reuteri .…”

Profiles and technological requirements of urogenital probiotics

“…These substances effectively inhibit pathogenic bacteria, are safe and do not possess any threat to healthy vaginal microbiota [73,116,[157][158][159][160][161][162][163]. Different bacteriocins have been published from strains isolated from the vaginal tract.…”

“…Stoyancheva et al [163] have shown the presence of gasserin A operon in some of the vaginal strains with bactericidal effect.…”