Studies On Epidemiology And Pathogenicity Of Genital Mycoplasma Infection

Mycoplasma genitalium (Mg) is a member of the Mollicutes class that colonizes human mucosal surfaces of urogenital tracts. Accumulating evidence supports that Mg is a common sexually transmitted infection (STI) pathogen that can cause non-gonococcal urethritis (NGU) in men and pelvic inflammatory disease (PID) in women. In addition, several studies have shown that Mg infection can increase the risk of human immunodeficiency virus (HIV) transmission and/or acquisition. However, there have been limited number of epidemiological studies on Mg infection worldwide and data on the prevalence of this pathogen among men who have sex with men (MSM) are especially scarce. MSM plays a significant role in the spread of HIV and other sexually transmitted diseases (STD). Recent studies revealed an increasing trend of HIV/STD prevalence in Chinese MSM. However, to date, limited reports on the prevalence of Mg infection in this population have been reported. As part of a large cross-sectional study aimed at investigating the epidemiology of Mg infection among high risk populations in China, this study aims:(i) to determine the prevalence of urethral and rectal Mg infection in MSM in Shenzhen, Guangdong Province, China, and (ii) to identify the potential risk factors related to Mg infection.Ureaplasma spp. is another member of the Mollicutes class. It has14known serovars and is separated into the following2new species:Ureaplasma urealyticum (serovars2/4/5and7-13) and Ureapalsma parvum (serovars1/3/6/14). Although common in healthy people, ureaplasmas are also frequently reported to be associated with non-gonococcal urethritis (NGU), pelvic inflammatory disease (PID), infertility, adverse pregnancy outcomes (APO), chorioamnionitis and bronchopulmonary dysplasia (BPD) in neonates. However, there is conflicting evidence concerning whether there are differences in virulence among Ureaplasma serovars. And limited epidemiological studies have observed the prevalence of each serovars among neither high risk nor general population. Moreover, there has been no published study to date that has investigated the differences in the pathogenicity of the14serovars of Ureaplasma spp. Thus, the objectives of this part are to establish a murine model of genital tract by14serovars of Ureaplamsa spp, and to evaluate differences in the pathogenicity of these14serotypes.Section1:The prevalence of urethral and rectal Mycoplasma genitalium among men who have sex with men in Shenzhen, China.Between January and May2010, a total of409MSM were recruited in Shenzhen, Guangdong Province, China. An anonymous questionnaire was used to collect information regarding their socio-demographic characteristics and sexual behaviors. In addition, first-void urine (FVU) samples and rectal swabs were collected for PCR-based Mg testing. Among the409participants,406valid FVU and405rectal swab samples collected. The overall Mg prevalence was8.1%(33/406,95%CI5.7%-10.6%), with a FVU positivity of3.4%(95%CI1.7%-5.4%) and a rectal positivity of5.4%(95%CI3.5%-7.7%). Multivariable logistic regression analyses indicating that urethral Mg infection was significantly associated with having more heterosexual behaviors (AOR7.16,95%CI1.89-27.13,) and having unprotected anal intercourse in the past six months (AOR4.80,95%CI1.40-16.47). Rectal Mg infection was significantly associated with HIV infection based on univariate logistic regression analysis (OR=4.49,95%CI1.18-17.12). In this study, we showed that Mg was more prevalent in MSM who had bisexual behaviors compared to those who only engaged in homosexual behaviors. Further work is needed to establish the mode of Mg transmission and to identify its relationship with HIV transmission. Meanwhile, more attention should be paid to Mg infection among MSMs, and especially bisexual MSMs, which might have critical implications for effective HIV/STD control in China.Section2:The pathogenicity of14serovars of Ureaplasma spps in the lower genital tract of female BALB/c miceThe objectives of this section are to establish a murine model of lower genital tract infection by14serotypes of Ureaplasma spp, and to evaluate the differences in pathogenicity of these14serovars. Female BALB/c mice of7-weeks old were randomly and equally divided into14infectious groups and two control groups. The presence of infection was determined on solid and liquid culture media. Tumor necrosis factor (TNF-α) and interleukin (IL)-1β expression in lower genital tract secretions was determined using ELSIA kit. And histological examination was used to evaluate the difference in pathogenicity in each serovar. The blank control group and estradiol group were negative for Uu after inoculation with a lower level of TNF-a around2.07-7.69pg/mL.The positive rates of mice among UUR groups were generally higher than that among UPA groups. Both of positive rate and color change unit (CCU) value in two groups reduced with time. Meanwhile, each group presented different changes in the expression of TNF-a and IL-1β. The expression of these factors were peaked at3days after infection among serotypes1and4group, but were peaked at14days and21days after infection among8/13groups and2/7/9/11/12/14groups. The main histopathological feature was interstitial infiltration of inflammatory cells in uterus. In addition, Uu13might be an infectious serotype without causing symptoms. Therefore, serotype1/3/14/4/8/11might be primary pathogenic types and the rest might be opportunistic pathogen.