Exploring the diversity of vaginal microbiota between healthy women and cervical cancer patients in India.

Introduction. Cervicovaginal diversity has been reported as a predictive biomarker for cervical cancer risk. We recently reported the bio-therapeutic potential of vaginal probiotics from healthy Indian women against vaginal pathogens, isolated from the invasive cervical cancer (ICC) patients.Gap Statement. The cervicovaginal microflora from cervical cancer patients has not yet been reported from Indian population.Aim. The present study aimed at comparing the cervicovaginal microbiome between healthy controls (HC) and ICC patients from the Indian population.Methodology. In total, 30 vaginal swabs (15 from HC and 15 from ICC) were subjected to 16S rRNA gene sequencing. Alpha diversity was evaluated by Shannon and Chao1 index; and beta diversity by principle coordinate analysis (PCoA) of weighted and unweighted UniFrac distances. The relative abundance of the microbial taxa was done according to linear discriminant analysis effect size (LEfSe).Results. Predominance of Staphylococcus spp. in ICC and Lactobacillus gasseri in HC groups was observed. Alpha-diversity was found to be higher in ICC as compared to HC but was statistically non-significant. LEfSe analysis revealed Bacteroides fragilis and Escherichia coli as the marker genera in ICC with a marked decrease in Lactobacillus sp. Contrarily, in HC, L. gasseri, L. iners and L. fermentum were found to be abundant.Conclusion. Differences in the vaginal microbiome between healthy and ICC women could help in the early prediction of cervical cancer risk and thus in designing prevention strategies.

Cervicovaginal microbiota isolated from healthy women exhibit probiotic properties and antimicrobial activity against pathogens isolated from cervical cancer patients.

Abnormal cervicovaginal microbiota play an important role in HPV persistence and progression to cervical cancer. The present study aimed at isolating and identifying potential probiotics from vaginal swabs of healthy women and evaluating their activity against vaginal pathogens isolated from cervical cancer patients. Based on probiotic, acid-bile tolerance and antimicrobial properties, 13 lactic acid bacteria (LAB) from the healthy group were identified by MALDI TOF MS (Matrix Assisted Laser Desorption and Ionisation, Time Of Flight Mass Spectrometry). Among these, four strains, Lactobacillus gasseri P36Mops, Limosilactobacillus fermentum P37Mws, Lactobacillus delbrueckii P31Mcs and Enterococcus faecium P26Mcm, exhibited significant antimicrobial activity against 8 vaginal pathogens (Staphylococcus haemolyticus P41Tcs, Escherichia coli P30Tcs, E. coli P79Bcm, Enterococus faecalis P29Mops, E. faecalis P50Tws, E. faecalis P68Tcb, S. haemolyticus P48Bcb and S. haemolyticus P58Bcb) isolated from precancerous and cervical cancer patients. 16S rRNA sequencing of four potential probiotics revealed congruency with the MALDI-TOF MS identification and phylogenetic analysis showed genetic relationship with previously reported LAB strains. The selected LAB showed strain specific hydrophobicity (35.88-56.70%), auto-aggregation (35.26-61.39%) and antibiotic susceptibility. Interestingly, L. gasseri P36Mops was resistant to five standard antibiotics routinely used against urogenital or vaginal infections. LCMS (Liquid Chromatography Mass Spectrometry) analyses of the CFS (cell-free supernatant) of the four potential probiotics revealed the presence of metabolites such as N-(1-deoxy-1-fructosyl)valine, hygroline, acetoxy-2-hydroxy-16-heptadecen-4-one, avocadyne 4-acetate, avocadyne 2-acetate, taraxinic acid glucosyl ester, 6-hydroxypentadecanedioic acid, with reported antimicrobial activity. The overall data suggest the bio-therapeutic potential of the identified vaginal probiotics against cervical cancer-associated pathogens.