A Study On Transmission Way Of The Pathogenic Agents From Vulvovaginal Candidiasis

Background:Vulvovaginal candidiasis (VVC) is a common vagina disease which is caused by various kinds of Candida, its incidence has remarkably increased year by year. Most women at least catch the disease one time during child-bearing period in her life, and approximately5%～10%patients are prone to develop recurrence vulvovaginal candidiasis (RVVC). The complicated etiopathogenisis and higher recurrence of VVC have to become aporia and hot spot in clinical practice, owning to multifarious factors in areas of pathogenic Candida and organism. Present domestic and abroad research mostly concentrate upon many risk factors such as host living habit, immune state, species of infected microorganism and microbial environment theory, and so on. Whether the transmission route having an effect on recurrence has not been defined. This research is carried out to identificate different types of gene fragment from Candida, which were isolated from vagina, anus and genitalia of sexual partners, to know well whether fungus is endogenous infection (anus or around of the patient), exogenous infection(sexual partner)or both of them. In order to provide experimental evidence for prevention and therapies efficaciously, it is helpfullyt to explain its mechanism of recurrence.Objective:To study the propagation mechanisms of pathogenic strains by using phenotypic identification, gene fragment identification and high-resolution melting curve technology, which collected from vagina, anus and genitalia of sexual partners in VVC or RVVC patients, thereby identifying their source and route of infection. This study properly may provide clinical molecule epidemiological survey for isolating Candida strains from patients with vulvovaginal candidiasis, and it is of great significance to elucidate its mechanism of recurrence.Methods:1. All of patients were recruited into the survey from June2011to December2011in department of dermatology or department of gynaecology and obstetrics in the Second Hospital of Lanzhou University. All groups of patients answered questionnaires about some common epidemiology information, including age of onset, education level, living habit, medication usage, clinical manifestation, and so on. Then derived secretions from the posterior fornix and anal secretions. Sexual partners of the patients accompanied or telephoned appointment came to the hospital for glans Candida separation, excluding patients with multiple sexual partners.2. To analysis the clinical data of VVC/RVVC patients and their sexual partners, the univariate analysis and multivariate logistic regression statistical methods were performed with SPSS17.0for Windows. And to analyze micro-ecological situation and the distribution of pathogens in VVC/RVVC patients and sexual partners in Lanzhou.3. To take vaginal secretions of patients which clinical diagnosis of VVC/RVVC and directly be examined with10%KOH for microscopical examination, then positive samples were cultured on Sabouraud-chloramphenicol glucose agar and purified three times. And routine biological identification, that were, germ tube test, chlamydospore test, CHROMagar culture medium, and API20C AUX system, were applied to further identify Candida pathogenic strains from clinical samples.4. The internal transcribed spacer (ITS) region of ribosomal DNA of Candida were amplified using the high-resolution melting curve technology, which can genotyping identification of Candida genes at the molecular biology level.Results:1. This analysis has shown that the major predisposing factors responsible for vulvovaginal candidiasis are mental stress, less body exercisework, taking contraceptive pils, using intrauterine device, regularly washing the vagina, and combined with other sexually transmitted diseases.2. Eighty-one strains have been isolated from the clinical samples, of which Candida albicans is still the main pathogens. The strains of Candida albicans is62(76.54%),19strains of-Non-Candida albicans,9strains of Candida glabrata,6strains of Candida parapsilosis,2strains of Candida tropicalis,1strain of Candida krusei,1strain of Candida dubliniensis. Candida strains collected from vagina and anus of the27female patients were the same, and their sexual partner’s glans has not find any Candida; Six couples of sexual partner were extracted with the same pathogenic Candida which isolated from vagina, anus or glans.3. Different types of Candida amplifying primers by high-resolution melting curve technology can create different melting curve peak shape, then accurately identificated by Candida genotyping.4. Most of VVC patients were endogenous infection (pathogenic origin from the vagina or anus), a small number of them were exogenous (sexually transmitted) infection.Conclusions:1. This study has shown the major predisposing factors responsible for VVC are mental stress, less body exercisework, taking contraceptive pills, using intrauterine device, regularly washing the vagina, and being accompanied by other STDs, especially mental stress, less body exercise, and combined with other sexually transmitted diseases were the most statistically significant factors.2. Candida albicans was still the predominant pathogen of vulvovaginal candidiasis, while the proportion of non-Candida albicans was obviously rising, in which the most isolation was Candida glabrata.3. High-resolution melting curve technology can directly identify a variety of Candida at the molecular level. It was time-saving, accurate, and clinically specific, making rapid identification of pathogenic Candida possible.4. The majority of VVC patients were endogenous infection, and small number was exogenous (sexually transmitted) infection. Sexual partners being treated in the same period can help reducing the recurrence of RVVC.