Molecular Epidemiology Of Chlamydia Trachomatis Infections Among Men Who Have Sex With Men And Meta-analysis Of Point-of-care Tests For Chlamydia

Chapter IAnatomical site prevalence and genoty pes of Chlamydia trachomatis infections among men who have sex with men:a multi-site study in ChinaBackground:The MSM population has become the key population to take spread of sexually transmitted infections including HIV/AIDS.However,there are relatively limited epidemiological data on anatomic infections of Chlamydia trachomatis(CT)and their genotyping distributions among MSM in China.Objective:The current study was aimed to investigate the prevalence and genotype distribution of infections at different anatomic sites exposed to sexual contacts among MSM recruited from three geographically different cities in China in order to provide more epidemiological profiles of the infections in this population.Methods:Specimens were collected using swabs from anorectal,pharyngeal,and urethral sites in 379 MSM.CT infection was determined by polymerase chain reaction and genotyping was based on sequences of the ompA gene.Results:Findings from the study showed that the overall prevalence of CT infections was 18.2%(95%confidence intervals[CI],13.9-22.5%)and the city-specific prevalence rates were significantly different(p=0.048).The infection was most common at the anorectal site(15.6%,95%CI 11.6-19.5%)followed by urethral(3.2%,95%CI 1.4-5.0%)and oropharyngeal sites(1.6%,95%CI 0.3-2.9%).Genotypes D and G were the most predominant CT strains in this population but the predominant genotype was different across the cities,indicating predominant genotype D in Nanjing and genotype G in Wuhan.No genotypes associated with lymphogranuloma venereum(LGV)were found in our population.CT infection was independently associated with infection of Neisseria gonorrhoeae(adjusted odds ratio[aOR]14.27,95%CI 6.02-33.83,p<0.001)and the age older than 40 years(aOR 0.37,95%CI 0.15-0.93,p=0.03).Conclusion:The prevalence of CT infections,particularly at anorectal area,is subtaintial among MSM in China,implying the needs to develop comprehensive interventions for CT infections in this high-risk population by providing active screening,and standardized treatment.It is also suggested that ad hoc surveys on CT infections and genotype determinations should be integrated into the epidemiological surveillance of MSM in China.Chapter IIPerformance of point-of-care tests for the detection of Chlamydia trachomatis infections:A systematic review and meta-analysisBackground:Convenient and effective detection methods are crucial to scale up detection of infections with Chlamydia trachomatis(CT).Point-of care test(POCT)provides one of the important means to achieve this goal.Antigen-based POCTs have been widely used,especially in developing countries.In recent years,POCTs based on nucleic acid detection(NAAT)have been increasingly developed and commercially available for clinical use.Objective:The current study was aimed to provide the updated profiles on diagnostic performance of available POCTs to detect genitourinary tract and anorectal infections with CT through a systematic literature review and meta analysis.Methods:The thematic words combined with free words were applied to search literatures.Two investigators in the research group independently searched the relevant literatures from PubMed and Embase databases published from January 2004 to October 2018.Then data extraction and literature quality evaluation were completed by the two investigators.Any non-concensus issues between the two investogators were discussed and solved by consulting the third investigator.If the data in the study was incomplete,the corresponding author was contacted via email for further information.For each included study,the sensitivity,specificity,positive predictive value,negative predictive value,diagnostic odds ratio(DOR)and 95%confidence intervals(CIs)were extracted from or calculated by using data from the literature.The diagnostic performance was evaluated using NAAT as the reference standard.STATA 14.0 was used for statistical analysis.Results:A total of 34 articles were finally included,including 14 POCTs based on antigen detection and 20 POCTs on nucleic acid detection to evaluate a total of 33,434 samples.The overall combined sensitivity,specificity and DOR of antigen-based POCTs were 56%(95%CIs 45%-67%),99%(95%CIs 98%-99%),86.1(95%CIs 45.6-162.7),respectively.The corresponding performance values for NAAT-based POCTs were 95%(95%CIs 93%-97%),99%(95%CIs 99%-100%)and 1,865.4(95%CIs 949.7-3,664.1),respectively.Conclusion:The diagnostic performance of NAAT-based CT POCTs is obviously better than that of antigen-based POCTs.Chapter ⅢOmpA-MLST(high resolution multi-locus sequencing typing)of Chlamydia trachomatis infection in multi-anatomical sites in MSMBackground:Men who have sex with men(MSM)is one of the key populations with infections of Chlamydia trachomatis(CT).Information on genotyping patterns of CT in MSM will be helpful for further understanding dynamics of the CT transmission in this specific population.It is known that the genotypes of CT(types L)related to lymphogranuloma venereum(LGV),which has been prevalent in European countries,has not yet been found in China.Objective:The current study was aimed to provide epidemiological data based on ompA-MLST typing among MSM recruited from three geographically different cities in China,and to further investigate whether the LGV-related CT types are occurred among the MSM population in these three study cities.Methods:A total of 77 CT positive samples were amplified and sequenced at 6 gene loci.OmpA-MLST typing was performed according to identifying ompA,CT058,CT144,CT 172,hctB and pbpB sequencing results.Results:D type(50.6%,n=39),G(27.3%,n=21),J(11.7%,n=9),F type(7.8%,n=6),E(1.3%,n=1),B(1.3%,n=1);D-109(12.9%,8/62),G-346(9.7%,6/62),D-11(6.5%,4/62),G-108(6.5%,4/62)were identified.There was no any sample identified as being infected with LGV-related genotypes L and the ST-52 and ST-58 types frequently reported abroad were not found in our population.Conclusion:OmpA typing results in our MSM population are basically consistent with those found in the previous studies.The CT genotype distribution of our population is different from other countries,preliminarily indicating a limited CT spread of this population within the country.