The Study Of Staphylococcus Aureus Colonization In Vagina And The Mechanism Of Its Regulation By Estrogen

Human micro-ecosystem was consisted of the normal microbiota,tissues,cells and metabolites.The vaginal microecology is a significant part of the human micro-ecological system.Once the vaginal flora is imbalance,vaginal infectious diseases would take occurrence.The common microflora in the vaginal microenvironment are: Lactobacillus,Staphylococcus aureus,Escherichia coli,Streptococcus agalactiae,and Klebsiella pneumoniae.Besides of Lactobacillus,Staphylococcus aureus is the most common vaginal parasite.However,there were less researches associated Staphylococcus aureus with female reproductive tract infections.Estrogen could increase the synthesis of glycogen in vaginal epithelial cells,and eventually promote the synthesis of vaginal lactic acid to maintain the weakly acidic environment of vagina.Regrettably,whether estrogen could affect the adhesion and colonization of Staphylococcus aureus in vaginal epithelial cells and its mechanism have not been reported up to now.In the first part of the study,we collected clinical samples,identify Staphylococcus aureus of female vaginal secretions in different estrogen states,and analyze the epidemiological risk factors of vaginal infections.The results revealed that Staphylococcus aureus infection was closely related to estrogen levels.In the second part,in vitro,further studies concerning the effect of gradient concentrations estrogen on Staphylococcus aureus were conducted.Estrogen was found to promote Staphylococcus aureus colonization in VK2/E6E7 cells in the vaginal mucosal epithelium,and related mechanisms were further explored.Part I Analysis of bacterial vaginitis susceptibility factors and differential culture of Staphylococcus aureus about vaginal secretion in women with different estrogen levelsObjectives: To investigate the differential characteristics of Staphylococcus aureus culturing in vaginal secretions with different estrogen states,and to analyze its susceptibility factors.Methods: A total of 235 vaginal secretion specimens from January 2017 to June 2017 were randomly collected from the obstetrics and gynecology clinics of the Nanjing Maternal and Child Health Hospital.Grouped by age and hormone level,the specimens of childbearing age group(<45 years old)were 152,including 48 cases in asymptomatic group and 104 group in bacterial vaginosis group;the specimens of the menopause or menopause group(≥45 years old)were 83,including 23 cases in asymptomatic group and 60 cases in bacterial vaginosis group.Besides,the sociodemographic information,sexual behavior and reproductive health characteristics were recorded,and Staphylococcus aureus in vaginal secretions were differential cultured and its colonies were counted.Results: Among the 235 vaginal secretion samples,there were 71 cases in the asymptomatic group(30.21%),164 cases in bacterial vaginosis group(69.79%),152 cases(64.68%)in the childbearing age group,and 83 cases in perimenopause or menopause group(35.32%).The results of data analysis indicated that the incidence of bacterial vaginosis was considerably high.What’s more,the colonies count of Staphylococcus aureus were significantly higher than that in women without vaginal infection.The incidence of bacterial vaginosis were higher in the perimenopause or menopause group than in the childbearing age group.Conversely,Staphylococcus aureus colony counts were higher in the childbearing age group than in the perimenopause or menopause group.And,the differences were statistically significant.Conclusion: Bacterial vaginosis is a common and frequently occurring disease in women,which is closely related to age,estrogen levels,frequency of sexual activity,number of sexual partners,birth history,history of previous reproductive tract infections,frequency of vulva cleansing,frequency of changing underwear,education and other factors.Moreover,the level of estrogen in the body may regulate the adhesion and colonization of Staphylococcus aureus in the vagina.Part II The study of estrogen effects on Staphylococcus aureus colonization in vginal epithelial cell Line VK2 / E6E7 and Its MechanismsObjectives: To explore the effect of 17β-estradiol on the colonization of Staphylococcus aureus in vaginal epithelial cells and to identify the relevant molecular mechanism.Methods: VK2/E6E7 cells and Staphylococcus aureus were cultured to explore the colonization and adhesion of Staphylococcus aureus in vitro with various time and concentration;to inspect adherence and colonization of Staphylococcus aureus in vitro with different 17β-estradiol concentration;to verify the effects of 17β-estradiol,estrogen receptor antagonist ICI82780 were added and the influence of 17β-estradiol on the adherence and colonization of Staphylococcus aureus in vitro was also assessed.Results: 3h after Staphylococcus aureus vaccination,the colony amount was the most in vitro,while the protein expression index of p ERα and p FAK was most at 0.5h of microbial vaccination;when the Staphylococcus aureus vaccination concentration was 104 CFU/ml,the colony amount was the most,and the protein expression index of p ERα and p FAK was the most at the same time;24h after the treatment of 17β-estradiol,the colony amount of Staphylococcus aureus was the most in vitro with 1000 n M 17β-estradiol,meanwhile the protein expression index of p ERα and p FAK was also the most;after the treatment of 10μM ICI82780 with different time,the colony amount of Staphylococcus aureus was significantly reduced in vitro,and the protein expression index of p ERα and p FAK also notablely decreased.Conclusion: Estrogen can promote the colonization of Staphylococcus aureus on VK2 / E6E7 cells,which may be regulated via the ERα/FAK signaling pathway.