Isolation And Identification Of Vaginal Lactobacilli From Healthy Women Of Childbearing Age

The normal vaginal ecosystem of the healthy women of childbearing age is predominantly composed with lactobacillus.These bacterium can inhibit vaginal pathogen microorganism through producing lactic acid,hydrogen peroxide, bacteriocin and other anti-microorganism substances,so as to maintain the normal vaginal physiological homeostasis.Clinical study has shown that lactobacilli that colonize in vagina can produce hydrogen peroxide and decrease the mobility of bacterial vaginosis,gonorrhea and HIV.In our study,we used 16S rRNA sequencing method to identify the major species of lactobacilli in 223 healthy women of childbearing age and analyzed their capacity to produce hydrogen peroxide.In the second part of our study,we mainly investigated the changes of vaginal lactobacilli with time course.We intend to provide some fundamental understanding of lactobacilli probiotic based on our results.â… Isolation and identification of vaginal lactobacilli from healthy women of childbearing ageObjective To determine the major species of vaginal lactobacilli in healthy Chinese women and their capacity to produce hydrogen peroxide.Methods Vaginal swab samples were collected from 223 healthy women of childbearing age.The samples were cultured for lactobacilli isolation in Rogosa and MRS medium.Bacterial DNA was extracted and the 16S rRNA was amplified by PCR and analyzed by nucleotide sequencing.The sequences were compared with existing data in GenBank.The identified lactobacilli were inoculated in MRS medium containing TMB to observe their capacity to produce H₂O₂ Results L. crispatus,L.jensenii and L.gasseri are the major species isolated from 223 healthy childbearing women,and account for 53.7%,27.9%and 10.3% respectively.Other rare species include L.vaginalis(2.4%),L.coleohominis (1.6%),L.johnsonii(1.6%),L.acidophilus(1.6%) and L.fermentum(1.6%). Most of these lactobacilli are capable to produce hydrogen peroxide,L. crispatus,L,jensenii and L.acidophilus are with higher potency.Conclusion L. crispatus,L.jensenii and L.gasseri are major species found in the vagina of healthy Chinese women.L.crispatus,L,jensenii and L.acidophilus are more capable to produce hydrogen peroxide.â…¡Study of changes of vaginal lactobacilli with time courseObjective To determine whether the major species of vaginal lactobacilli changes with time course.Methods Sixteen healthy women of childbearing age who have been confirmed with the presence of lactobacilli in vagina were followed up for about 3 months.The vaginal samples were collected during the interval of menstruation.The methods of isolation,culture and identification of lactobacilli were described in the first section of this study.Results The vaginal lactobacilli species of 10 subjects did not changed during the 3-month period.The other six subjects' vaginal lactobacilli changed or were unable to be detected. The species change or undetectable of vaginal lactobacilli was independent of age, menstruation time,history of pregnancy and childbearing and contraception methods.Conclusion Most(62.5%) of vaginal lactobacilli does not change with time course,especially L.crispatus.L.crispatus would be the candidate of probiotic therapy.