Dataset Information

Chlamydia trachomatis transmission between the oropharynx, urethra and anorectum in men who have sex with men: a mathematical model.

ABSTRACT: BACKGROUND:It has been presumed that Chlamydia trachomatis is transmitted between men only through anal or oral sex, but no mathematical models have tested this presumption. METHODS:To test this presumption, we created 20 compartmental mathematical models of different sexual practices that included both oral and anal sex and calibrated these models to the observed rates of Chlamydia trachomatis infection at three anatomical sites from 4888 men who have sex with men (MSM) in Melbourne Sexual Health Centre during 2018-2019. RESULTS:A model that included only oral and anal sex could replicate the observed rates of single-site infection at the oropharynx, urethra and rectum alone, but could not replicate infection at more than one of these sites (multisite). However, if we included transmission from sexual practices that followed one another in the same sexual episode (e.g. saliva contamination of the penis from oral sex transmitting chlamydia to the rectum by anal sex), we significantly improved the calibration of multisite infection rates substantially. CONCLUSIONS:Our modelling study suggests that transmission routes other than just oral and anal sex are necessary to explain the high rate of Chlamydia trachomatis infection at more than one site.

SUBMITTER: Xu X

PROVIDER: S-EPMC7670797 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Chlamydia trachomatis transmission between the oropharynx, urethra and anorectum in men who have sex with men: a mathematical model.

Xu Xianglong X Chow Eric P F EPF Ong Jason J JJ Hoebe Christian J P A CJPA Zou Zhuoru Z Hocking Jane S JS Fairley Christopher K CK Zhang Lei L

BMC medicine 20201117 1

<h4>Background</h4>It has been presumed that Chlamydia trachomatis is transmitted between men only through anal or oral sex, but no mathematical models have tested this presumption.<h4>Methods</h4>To test this presumption, we created 20 compartmental mathematical models of different sexual practices that included both oral and anal sex and calibrated these models to the observed rates of Chlamydia trachomatis infection at three anatomical sites from 4888 men who have sex with men (MSM) in Melbou ...[more]

PMID: 33198750

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Project description:Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) represent the most common agents of sexually transmitted rectal infections among men having sex with other men (MSM). In this study, we assessed the bacterial composition of the rectal microbiota associated with CT and/or NG infections in a cohort of men reporting unsafe rectal intercourse. A total of 125 rectal swabs were collected and four groups were compared: non-infected subjects (n = 53), patients with CT (n = 37), or NG rectal infection (n = 17) and patients with contemporary positivity for CT/NG (n = 18). CT and NG infections were detected by a real-time commercial test and the rectal microbiota composition was analyzed from rectal swabs through sequencing of the hypervariable V3-V4 regions of the 16S rRNA gene. The rectal microbiota of all subgroups was dominated by Prevotellaceae, Enterobacteriaceae, and Ruminococcaceae families. Irrespective of the analyzed subgroup, we found that the rectal environment of all the enrolled MSM was rich in Prevotella and Escherichia genera. Moreover, a shift in the bacterial composition between patients with sexually transmitted rectal infections and controls was noticed: infected patients were characterized by a depletion of Escherichia species, associated with an increase of anaerobic genera, including Peptoniphilus, Peptostreptococcus, and Parvimonas. Overall, the presence of rectal symptoms did not significantly modify the rectal microbiota profiles among the four groups of analyzed patients. We confirmed that HIV-positive patients are characterized by a lower bacterial richness than HIV-negative subjects. However, we found that the presence of HIV has a different impact on bacterial rectal communities compared to CT and NG infections, modifying the relative abundance of several genera, including Gardnerella, Lactobacillus, Corynebacterium, and Sutterella. Information about the rectal microbiota composition in CT and NG infections could shed light on the pathogenesis of these conditions and could contribute to the onset of new strategies for their control.

Project description:To determine the prevalence of anorectal Chlamydia trachomatis serovars in a group of men who have sex with men (MSM) with high risk sexual behaviour, attendees at a sexually transmitted infection (STI) unit from a region in Northwest Spain.Retrospective and descriptive study of all swabs obtained from all MSM attendees at an STI unit, from 2007 to 2011. Retrospective ethical approval was granted by the Ethical Regional Committee of Clinical Investigation of the Principality of Asturias.The STI clinic in Oviedo, Spain, offers screening and free-of-charge treatment to about 3646 patients per year.303 symptomatic and asymptomatic consecutive and unselected MSM patients (mean age 36.7 and range 21-55 years) were evaluated for anorectal chlamydial infection.C trachomatis DNA extraction and detection in all rectal and in 36 urethral swabs. Characterisation of C trachomatis genotypes through sequencing of ompA gene amplicons and further phylogenetic tree analysis.We found 40 (13. 2%) positive rectal samples. The distribution of genotypes was E (37. 5%) followed by G (25%), D (12. 5%), J (10%) and L2b (5%).25 (62.5%, 95% CI 46.2 to 78.7) of the chlamydia-infected MSM showed clinical manifestations while 15 (37.5%, 95% CI 21.25 to 53.75) reported no symptoms. Concurrent infection with other STIs was documented in 27 (67.5%, 95% CI 51.7 to 83.2) patients. The most frequently reported clinical symptom was anal ulcer (7 cases, 17.5%; 95% CI 4.47 to 30.52). E genotype was mostly detected in asymptomatic patients. There were non-E genotypes detected in 21 (84%, 95% CI 63.9 to 95.5) of 25 symptomatic patients (p<0.001).The first two confirmed cases of lymphogranuloma venereum (LGV) in MSM in Asturias are reported, probably indicating the increase of this infection. The Spanish C trachomatis laboratory-based surveillance system may underlie an underestimated number of chlamydial infections. Whenever mild and atypical symptoms exist, laboratory evaluation would contribute to the early implementation of appropriate therapy and prevent LGV dissemination.

Project description:Chlamydia trachomatis is one of the most prevalent bacterial sexually transmitted infection in China. Although C. trachomatis genotypes can be discriminated by outer membrane protein gene (ompA) sequencing, currently available methods have limited resolutions. This study used a high-resolution genotyping method, namely, multilocus variable number tandem-repeat analysis with ompA sequencing (MLVA)-ompA, to investigate the local epidemiology of C. trachomatis infections among men who have sex with men (MSM) and men who have sex with women (MSW) attending a sexually transmitted diseases (STD) clinic in Guangzhou, China.Rectal specimens from MSM and urethral specimens from MSW were collected between January 2013 and July 2014 at the Guangdong Provincial Center STD clinic. The specimens were sent to the laboratory for analyses. All specimens that were tested positive for C. trachomatis by the commercial nucleic acid amplification tests were genotyped by MLVA-ompA.Fifty-one rectal specimens from MSM and 96 urethral specimens from MSW were identified with C. trachomatis. One hundred and forty-four of the 147 specimens were fully genotyped by MLVA-ompA. Rectal specimens from MSM were divided into four ompA genotypes and urethral specimens from MSW into nine genotypes. No mixed infections were found among all specimens. The most frequent genotypes were D, G, J, E and F. All specimens were further divided into 46 types after ompA genotyping was combined with MLVA. Genotypes D-8.7.1 and G-3.4a.3 were the most frequent among MSM, whereas genotypes D-3.4a.4, E-8.5.1, F-8.5.1, and J-3.4a.2 were the most frequent subtypes among MSW. The discriminatory index D was 0.90 for MLVA, 0.85 for ompA, and 0.95 for MLVA-ompA.The most prevalent MLVA-ompA genotypes were significantly different between MSM and MSW from Guangzhou, China. Moreover, MLVA-ompA represented a more favorable degree of discrimination than ompA and could be a reliable complement for ompA for the routine subtypes of C. trachomatis.

Dataset Information

Chlamydia trachomatis transmission between the oropharynx, urethra and anorectum in men who have sex with men: a mathematical model.

Publications

Chlamydia trachomatis transmission between the oropharynx, urethra and anorectum in men who have sex with men: a mathematical model.

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