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Mozambique is making progress towards elimination of trachoma as a public health problem, but in some districts trachomatous inflammation-follicular (TF) prevalence remains above the 5% elimination threshold despite years of various interventions, including antibiotic mass drug administration. To characterize transmission in four districts, we incorporated testing of ocular infection and serology into routine trachoma impact surveys (TIS) in August 2022. We examined residents aged ≥ 1 year for trachoma and collected information on household water, sanitation, and hygiene. Among children aged 1-9 years, we tested conjunctival swabs for Chlamydia trachomatis nucleic acid and dried blood spots for C. trachomatis antibodies. We modeled age-dependent seroprevalence to estimate seroconversion rate (SCR). We examined 4841 children aged 1-9 years. TF prevalence ranged between 1.1 and 6.0% with three districts below the 5% threshold. PCR-confirmed infection prevalence ranged between 1.1 and 4.8%, and Pgp3 seroprevalence ranged between 8.8 and 24.3%. Pgp3 SCR was 1.9 per 100 children per year in the district with the lowest TF prevalence. Two other districts with TF

BACKGROUND: Promotion of facial cleanliness is recommended for the elimination of blinding trachoma, largely because of observational studies that have found an association between various measures of facial uncleanliness and trachoma. However, when a field grader assesses both facial cleanliness and trachoma, associations may be biased. Assessment of photographs of the face and conjunctiva by masked graders may provide a less biased estimate of the relationship between facial cleanliness and trachoma. METHODS: Face photographs, conjunctival photographs, and conjunctival swabs were obtained on a random sample of 0-9-year-old children from each of 40 communities in Amhara region, Ethiopia. Face photographs were assessed for the presence of seven measures of an unclean face (i.e., wet nasal discharge, dry nasal discharge, wet ocular discharge, dry ocular discharge, food, dust/dirt, and flies) by three independent masked photo-graders. Conjunctival photographs were similarly graded in a masked fashion for signs of clinically active trachoma. Conjunctival swabs were processed for Chlamydia trachomatis DNA. RESULTS: Of 2073 children with complete data, 808 (39%) had evidence of clinically active trachoma, 150 (7%) had evidence of ocular chlamydia infection, and 2524 (91%) had at least one measure of an unclean face. Dry ocular discharge had the strongest association with clinically active trachoma (age- and sex-adjusted prevalence ratio [PR] 1.4, 95% CI 1.2-1.6) and ocular chlamydia infection (PR 1.9, 95%CI 1.3-2.9), although significant associations were observed between each of the measures of facial uncleanliness and trachoma. CONCLUSIONS: Masked assessment of face and conjunctival photographs confirmed prior observational studies that have noted associations between various measures of facial uncleanliness and trachoma. The causal relationship between facial uncleanliness and trachoma is unclear since many features used to measure facial cleanliness (e.g., ocular discharge, nasal discharge, and flies) could be consequences of antecedent ocular chlamydia infection. TRIAL REGISTRATION: NCT02754583, clinicaltrials.gov.

Millions of doses of azithromycin are distributed each year for trachoma, yet the treatment efficacy of a single dose of azithromycin for ocular Chlamydia infection has not been well characterized. In this study, four villages in Niger received a mass azithromycin distribution for trachoma. All 426 children aged 0-5 years residing in the study villages were offered conjunctival swabbing every 6 months to test for ocular Chlamydia trachomatis. Among the children infected with ocular Chlamydia before treatment, 6% (95% CI: 2-15%) tested positive for ocular Chlamydia infection 6 months later, and 15% (95% CI: 7-28%) tested positive 12 months later. The most important predictor of post-treatment ocular Chlamydia infection was pretreatment ocular Chlamydia infection (relative risk: 3.5, 95% CI: 1.3-9.4). Although the 6-monthly monitoring schedule was suboptimal for testing the treatment efficacy of an antibiotic, these findings are nonetheless consistent with high treatment efficacy of a single dose of azithromycin and suggest that additional interventions might be most effective if targeted to those children infected prior to treatment.

ObjectivePregnant and postpartum women (PPW) in Southern Africa are at increased risk of acquiring HIV and curable sexually transmitted infections (STIs). Oral pre-exposure prophylaxis (PrEP) is safe and effective to use during pregnancy to reduce HIV acquisition and vertical transmission. Point-of-care (POC) STI testing can identify PPW at risk of HIV and facilitate risk-differentiated and person-centred counselling to improve PrEP initiation, persistence and adherence. We evaluated the impact of POC STI testing compared with STI syndromic management on PrEP outcomes among PPW in Cape Town, South Africa.MethodsThe STI and PrEP in Pregnancy Study enrolled PPW without HIV and ≤34 weeks pregnant at their regular antenatal care visit with follow-up after 1 month. PPW were randomised to receive POC STI testing or STI syndromic management. PPW randomised to POC STI testing self-collected vaginal swabs for Chlamydia trachomatis, Neisseria gonorhoeae and Trichomonas vaginalis (Cepheid GeneXpert) testing and were offered same-day treatment if diagnosed. We compared PrEP initiation at baseline, PrEP prescription refill at 1 month (persistence) and adherence through tenofovir-diphosphate detection in dried blood spots by randomisation arm. In a secondary analysis, we evaluated the association between an STI diagnosis (positive STI test or reporting STI symptoms) with PrEP outcomes.ResultsWe enrolled and randomised 268 pregnant women. Twenty-eight per cent of women were diagnosed with ≥1 STI. Overall, 65% of women initiated and 79% persisted on PrEP with no significant differences by randomisation arm. Secondary analysis demonstrated that an STI diagnosis (positive STI test or reporting STI symptoms) was associated with higher PrEP initiation (adjusted relative risk=1.28; 95% CI 1.08 to 1.52), controlling for arm, maternal and gestational age.ConclusionsPOC STI testing was not associated with PrEP initiation or persistence relative to syndromic management. However, improving STI diagnosis by supplementing syndromic management with POC STI testing could improve PrEP initiation among PPW.Trial registration numberNCT03902418; Clinical Trials.gov; 1 April 2019.

BACKGROUND: A rapid and affordable point-of-care test is a priority for Neisseria gonorrhoeae control. WHO and Foundation for Innovative New Diagnostics (FIND) have a target product profile for a non-molecular N gonorrhoeae rapid point-of-care test that requires a clinical sensitivity of greater than 80% and a specificity over 95% to be considered useful in syndromic management; test turnaround time should be 30 min or under, and the test should cost less than US$3. A novel lateral flow assay (LFA) was developed to achieve that profile. METHODS: In this cross-sectional study we evaluated the performance of the novel N gonorrhoeae lateral flow assay (NG-LFA) at the primary health-care level in South Africa. Male patients with urethral discharge syndrome and female patients with vaginal discharge syndrome were recruited from five primary health-care facilities in the Buffalo City Metropolitan Municipality health district of South Africa. First-void urine specimens and nurse-collected vaginal swabs were tested in-facility with the NG-LFA and Xpert CT/NG PCR assay. N gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed on all LFA positive specimens. FINDINGS: Between March 7, and Sept 19, 2022, we enrolled 200 male patients with urethral discharge and 200 female patients with vaginal discharge. The median age of male patients was 24 years (IQR 21-31 years), and the median age of female patients was 25 years (IQR 21-32 years). In addition, 23 male patients and 12 female patients who presented at the facility with a partner notification slip were enrolled of whom one (4%) and five (42%) were symptomatic, respectively. NG-LFA and Xpert results were available for all participants. In urine specimens, NG-LFA sensitivity was 96·1% (Wilson 95% CI 91·2-98·3; 123 LFA-positive among 128 PCR-positive specimens) and 91·7% in vaginal swab specimens (78·2-97·1; 33 LFA-positive among 36 PCR-positive). The specificity was 97·2% in urine specimens (90·4-99·2; 70 LFA-negative among 72 PCR-negative) and 96·3% in vaginal specimens (92·2-98·3; 158 LFA-negative among 164 PCR-negative). In 156 LFA-positive specimens, NG-MAST showed 93 different sequence types. INTERPRETATION: The novel NG-LFA had excellent clinical sensitivity and specificity in symptomatic male and female patients. The test met the optimal requirement for sensitivity and the minimal requirement for specificity specified in the target product profile. NG-LFA could provide an important tool to optimise clinical management and reduce excess antibiotic use in settings without direct access to laboratory testing. FUNDING: Global Antimicrobial Resistance Innovation Fund (GAMRIF) via FIND and National Institutes of Health.

Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterium globally. Endocervical and vaginal microbiome interactions are rarely examined within the context of Ct or among vulnerable populations. We evaluated 258 vaginal and 92 paired endocervical samples from Fijian women using metagenomic shotgun sequencing. Over 37% of the microbiomes could not be classified into sub-community state types (subCSTs). We, therefore, developed subCSTs IV-D0, IV-D1, IV-D2, and IV-E-dominated primarily by Gardnerella vaginalis-to improve classification. Among paired microbiomes, the endocervix had a significantly higher alpha diversity and, independently, higher diversity for high-risk human papilloma virus (HPV) genotypes compared to low-risk and no HPV. Ct-infected endocervical networks had smaller clusters without interactions with potentially beneficial Lactobacillus spp. Overall, these data suggest that G. vaginalis may generate polymicrobial biofilms that predispose to and/or promote Ct and possibly HPV persistence and pathogenicity. Our findings expand on the existing repertoire of endocervical and vaginal microbiomes and fill in knowledge gaps regarding Pacific Islanders.

BackgroundThe Centers for Disease Control and Prevention recommends that men who have sex with men (MSM) get tested annually for urethral and rectal chlamydia (CT) and gonorrhea (NG), and pharyngeal NG. There are no national recommendations to screen women and heterosexual men at extragenital sites. We assessed extragenital CT/NG screening among men and women at Louisiana's Parish Health Units (PHU).MethodsThe Louisiana STD/HIV/Hepatitis Program piloted extragenital screening at 4 PHUs in February 2016 and expanded to 11 PHUs in 2017. Sexual histories were used to identify gender of sex partners and exposed sites. Because of billing restrictions, up to 2 anatomical sites were tested for CT/NG.ResultsFrom February 2016 to June 2019, 70,895 urogenital and extragenital specimens (56,086 urogenital, 13,797 pharyngeal, and 1,012 rectal) were collected from 56,086 patients. Pharyngeal CT positivity was 160 of 7,868 (2.0%) among women, 54 of 4,838 (1.1%) among men who have sex with women (MSW) and 33 of 1,091 (3.0%) among MSM. Rectal CT positivity was 51 of 439 (11.6%) among women and 95 of 573 (16.6%) among MSM. Pharyngeal NG positivity was 299 of 7,868 (3.8%) among women, 222 of 4,838 (4.6%) among MSW, and 97 of 1,091 (8.9%) among MSM. Rectal NG positivity was 20 of 439 (4.6%) among women and 134 of 573 (23.4%) among MSM.Urogenital-only screening would have missed: among women, 173 of 3,923 (4.4%) CT and 227 of 1,480 (15.3%) NG infections; among MSW, 26 of 2,667 (1%) CT and 149 of 1,709 (8.7%) NG infections; and among MSM, 116 of 336 (34.5%) CT and 127 of 413 (42.1%) NG infections.ConclusionsMany CT/NG infections would have been missed with urogenital-only screening. Men who have sex with men had much higher extragenital infection rates than women and MSW.

BackgroundContinued high incidence of HIV and other STIs, paired with rising antibiotic resistance to a number of existing treatments, warrants the development of new pharmaceutical approaches for STI prevention. Multipurpose prevention technologies (MPTs) offer an innovative approach for expanding HIV/STI prevention. The majority of MPT product candidates currently in development include HIV prevention, while only half include compounds active against non-HIV STIs.MethodsThis narrative review focuses on compounds in preclinical development (in vitro and in vivo) through phase 3 clinical trials with activity against one or more of the following infections: HIV, HSV-1, HSV-2, Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, and Trichomonas vaginalis. Bacterial vaginosis is included due to its association with increased risk of STIs. The focus is on compounds with novel mechanisms of action and prophylactic and/or therapeutic potential. Articles published in PubMed between 2011 and 2021, NIH RePorter and conference abstracts and proceedings between 2020 and 2021 were searched. Excluded from the review are compounds that are already being used in MPT product candidates.Main resultsThere is a growing pipeline of compounds targeting viral STIs, many of which have successfully transitioned from preclinical to clinical stages of development. However, the product development pipeline remains limited for compounds that target bacterial STIs.ConclusionsThe paucity of new pharmaceutical approaches for STI prevention, particularly non-HIV STIs, remains a public health gap. Future funding priorities should include STI prevention research. Despite limited attention to STI prevention in the development of MPTs, many research institutions worldwide are working on discoveries of new compounds, exploring new indications for existing drugs or on innovative drug delivery mechanisms. Our findings can be used to connect researchers across the globe to advance the development of compounds that have potential as active pharmaceutical ingredients in future MPTs.

Objectives: This study aimed to investigate the factors associated with the spontaneous clearance of Chlamydia trachomatis, a phenomenon that, despite a growing body of literature, remains understudied in the context of women in China. Methods: Spontaneous clearance was defined as the transition from a positive to negative Chlamydia status over time without the use of antichlamydial therapy. Data from 5935 women aged 18 years and older who participated in the Clinical-Based Health Check program were analyzed. Eligible participants had no history of Neisseria gonorrhoeae infection, pelvic inflammatory disease, recent antibiotic use, or pregnancy and had an interval between the screening and follow-up visits of more than 3 days. Logistic regression was used to identify factors influencing spontaneous clearance. Results: Spontaneous clearance occurred in 23.9% (50/209) of the participants, typically with a median interval of 27 days. Significant factors included an interval >45 days, an age >35 years, the use of an intrauterine device (IUD), and the presence of clue cells. Conclusion: Spontaneous clearance of C. trachomatis is significantly affected by age, the interval between two tests, IUD use, and the presence of clue cells. Screening strategies should prioritize women under 35 years of age who do not use IUDs and test negative for clue cells for more effective chlamydia prevention and management.

BackgroundSexually transmitted infections (STIs) during pregnancy are associated with adverse birth outcomes, including preterm birth, low birth weight, perinatal death, and congenital infections such as increased mother-to-child HIV transmission. Prevalence of STIs among pregnant women in South Africa remains high, with most women being asymptomatic for their infection(s). Unfortunately, most STIs remain undetected and untreated due to standard practice syndromic management in accordance with World Health Organization (WHO) guidelines. Although lab-based and point-of-care molecular tests are available, optimal screening strategies during pregnancy, their health impact, and cost-effectiveness are unknown.MethodsWe will implement a 3-arm (1:1:1) type-1 hybrid effectiveness-implementation randomized-controlled trial (RCT). We will enroll 2500 pregnant women attending their first antenatal care (ANC) visit for their current pregnancy at participating health facilities in Buffalo City Metro District, Eastern Cape Province, South Africa. Participants allocated to arms 1 and 2 (intervention) will receive GeneXpert® point-of-care diagnostic testing for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis, with same-day treatment for detected infection(s). Arm 1 will additionally receive a test-of-cure 3 weeks post-treatment, while Arm 2 will receive a repeat test at 30-34 weeks' gestation. Those allocated to Arm 3 will receive syndromic management (standard-of-care). The RE-AIM framework will be used to guide collection of implementation indicators to inform potential future scale up. Primary outcome measures include (1) frequency of adverse birth outcomes among study arms, defined by a composite measure of low birth weight and pre-term delivery, and (2) change in STI prevalence between baseline and birth outcome among intervention arms and compared to standard-of-care. Estimates and comparative costs of the different screening strategies relative to standard-of-care and the costs of managing adverse birth outcomes will be calculated. Cost-effectiveness will be assessed per STI and disability-adjusted life year averted.DiscussionThis trial is the first RCT designed to identify optimal, cost-effective screening strategies that decrease the burden of STIs during pregnancy and reduce adverse birth outcomes. Demonstrating the impact of diagnostic screening and treatment, compared to syndromic management, on birth outcomes will provide critical evidence to inform changes to WHO guidelines for syndromic management of STIs during pregnancy.Trial registrationClinicalTrials.gov NCT04446611 . Registered on 25 June 2020.

BackgroundSexually transmitted infections (STIs) during pregnancy may increase the risk of adverse pregnancy outcomes. STI syndromic management is standard of care in South Africa but has its limitations. We evaluated the impact of diagnosing and treating curable STIs during pregnancy on adverse pregnancy and birth outcomes.MethodsWe combined data from two prospective studies of pregnant women attending public sector antenatal care (ANC) clinics in Tshwane District and Cape Town, South Africa. Pregnant women were enrolled, tested and treated for STIs. We evaluated the association between any STI at the first ANC visit and a composite adverse pregnancy outcome (miscarriage, stillbirth, preterm birth, early neonatal death, or low birthweight) using modified Poisson regression models, stratifying by HIV infection and adjusting for maternal characteristics.ResultsAmong 619 women, 61% (n = 380) were from Tshwane District and 39% (n = 239) from Cape Town; 79% (n = 486) were women living with HIV. The prevalence of any STI was 37% (n = 228); C. trachomatis, 26% (n = 158), T. vaginalis, 18% (n = 120) and N. gonorrhoeae, 6% (n = 40). There were 93% (n = 574) singleton live births, 5% (n = 29) miscarriages and 2% (n = 16) stillbirths. Among the live births, there were 1% (n = 3) neonatal deaths, 7% (n = 35) low birthweight in full-term babies and 10% (n = 62) preterm delivery. There were 24% (n = 146) for the composite adverse pregnancy outcome. Overall, any STI diagnosis and treatment at first ANC visit was not associated with adverse outcomes in women living with HIV (adjusted relative risk (aRR); 1.43, 95% CI: 0.95-2.16) or women without HIV (aRR; 2.11, 95% CI: 0.89-5.01). However, C. trachomatis (aRR; 1.57, 95% CI: 1.04-2.39) and N. gonorrhoeae (aRR; 1.69, 95% CI: 1.09-3.08), were each independently associated with the composite adverse outcome in women living with HIV.ConclusionTreated STIs at the first ANC visit were not associated with adverse pregnancy outcome overall. In women living with HIV, C. trachomatis or N. gonorrhoeae at first ANC were each independently associated with adverse pregnancy outcome. Our results highlights complex interactions between the timing of STI detection and treatment, HIV infection and pregnancy outcomes, which warrants further investigation.

OBJECTIVE: STIs remain a global public health problem with a high burden among pregnant women. STIs in pregnant women may lead to various adverse pregnancy outcomes. In most sub-Saharan African countries, syndromic management is used for screening and treatment of STIs. We aimed to update and summarise pooled prevalence of curable STIs and bacterial vaginosis (BV) among pregnant women in sub-Saharan Africa. METHODS: Electronic databases and reference lists of relevant published and unpublished studies were searched from March 2015 to October 2020. Studies were included if they estimated prevalence of Chlamydia trachomatis (CT), Trichomonas vaginalis (TV), Neisseria gonorrhoeae (NG), Treponema pallidum (syphilis), Mycoplasma genitalium (MG) and BV among pregnant women in sub-Saharan Africa. Meta-analyses were performed with observed prevalences corrected for diagnostic errors to estimate the pooled prevalence of diagnosed infections by region. RESULTS: A total of 48 studies met the inclusion criteria, providing 85-point prevalence estimates for curable STIs and BV. Pooled prevalence estimates (with 95% CI and number of women tested) were as follows: MG: 13.5% (4.0-27.2, n=1076); CT: 10.8% (6.9-15.5, n=6700); TV: 13.8% (10.0-18.0, n=9264); NG: 3.3% (2.1-4.7, n=6019); syphilis: 2.9% (2.0-4.0, n=95 308) and BV: 36.6% (27.1-46.6, n=5042). By region, BV was the most prevalent and ranged from 28.5% (24.5-32.8, n=1030) in Eastern Africa to 52.4% (33.5-70.9, n=2305) in Southern Africa; NG had the lowest prevalence, ranging from 1.4% (95% CI 0.1 to 3.1, n=367) in Central Africa to 4.4% (95% CI 2.6 to 6.4, n=4042) in Southern Africa. CONCLUSION: The prevalence of curable STIs and BV in sub-Saharan Africa is substantial in pregnant women but most prevalent in Southern Africa where HIV prevalence is highest. It is crucial to integrate screening of curable STIs into antenatal care programmes that have previously focused on diagnosis and treatment of syphilis and HIV.

BackgroundHighly efficacious oral pre-exposure prophylaxis (PrEP) is the global standard for human immunodeficiency virus (HIV)-1 prevention, including in clinical trials of novel PrEP agents using active-comparator designs. The analysis assessed whether incident sexually transmitted infections (STIs) can serve as a surrogate indicator of HIV-1 incidence that might occur in the absence of PrEP.MethodsWe analyzed data from 3256 women randomized to placebo groups of oral and vaginal PrEP trials (MTN-003/VOICE and MTN-020/ASPIRE). Regression modeling assessed the correlation between incident individual STIs (Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis, each considered separately) and incident HIV-1.ResultsAcross 18 sites in 4 countries (Malawi, South Africa, Uganda, Zimbabwe), STI and HIV-1 incidences were high: HIV-1 4.9, N gonorrhoeae 5.3, C trachomatis 14.5, and T vaginalis 7.1 per 100 person-years. There was limited correlation between HIV-1 incidence and incidence of individual STIs: N gonorrhoeae (r = 0.02, P = .871), C trachomatis (r = 0.49, P =

Chlamydia trachomatis is a sexually transmitted pathogen and a global public health concern. Little is known about the microbial composition and function across endocervical, vaginal, and rectal microbiomes in the context of C. trachomatis infection. We evaluated the microbiomes of 10 age-matched high-risk Fijian women with and without C. trachomatis using metagenomic shotgun sequencing (MSS). Lactobacillus iners and Lactobacillus crispatus dominated the vagina and endocervix of uninfected women. Species often found in higher relative abundance in bacterial vaginosis (BV)-Mageeibacillus indolicus, Prevotella spp., Sneathia spp., Gardnerella vaginalis, and Veillonellaceae spp.-were dominant in C. trachomatis-infected women. This combination of BV pathogens was unique to Pacific Islanders compared to previously studied groups. The C. trachomatis-infected endocervix had a higher diversity of microbiota and microbial profiles that were somewhat different from those of the vagina. However, community state type III (CST-III) and CST-IV predominated, reflecting pathogenic microbiota regardless of C. trachomatis infection status. Rectal microbiomes were dominated by Prevotella and Bacteroides, although four women had unique microbiomes with Gardnerella, Akkermansia, Bifidobacterium, and Brachyspira. A high level of microbial similarity across microbiomes in two C. trachomatis-infected women suggested intragenitorectal transmission. A number of metabolic pathways in the endocervix, driven by BV pathogens and C. trachomatis to meet nutritional requirements for survival/growth, 5-fold higher than that in the vagina indicated that endocervical microbial functions are likely more diverse and complex than those in the vagina. Our novel findings provide the impetus for larger prospective studies to interrogate microbial/microbiome interactions that promote C. trachomatis infection and better define the unique genitorectal microbiomes of Pacific Islanders. IMPORTANCE Chlamydia trachomatis is the primary cause of bacterial sexually transmitted infections worldwide, with a disturbing increase in annual rates. While there is a plethora of data on healthy and pathogenic vaginal microbiomes-defining microbial profiles and associations with sexually transmitted infections (STIs)-far fewer studies have similarly examined the endocervix or rectum. Further, vulnerable populations, such as Pacific Islanders, remain underrepresented in research. We investigated the microbial composition, structure, and function of these anatomic microbiomes using metagenomic shotgun sequencing among a Fijian cohort. We found, primarily among C. trachomatis-infected women, unique microbial profiles in endocervical, vaginal, and rectal microbiomes with an increased diversity and more complex microbial pathways in endocervical than vaginal microbiomes. Similarities in microbiome composition across sites for some women suggested intragenitorectal transmission. These novel insights into genitorectal microbiomes and their purported function require prospective studies to better define Pacific Islander microbiomes and microbial/microbiome interactions that promote C. trachomatis infection.

Research using nucleic acid amplification tests (NAATs) have repeatedly found rectal and oropharyngeal infections with Chlamydia trachomatis and Neisseria gonorrhoeae to be common and potentially more difficult to treat than genital infections. Unfortunately, public health and patient care efforts have been hampered by the lack of FDA-cleared NAATs with claims for anorectal or oropharyngeal samples. At the time of the initiation of this study, no commercially available assays had these claims. We formed a novel partnership among academic institutions and diagnostic manufacturers to address this public health need. From May 2018 through August 2019, we recruited 1108 women, 1256 men, and 26 transgender persons each of whom provided 3 anal and 3 oropharyngeal swab specimens. The 3 anal swabs were pooled into a single transport tube as were the 3 oropharyngeal swabs. The performance of each of three study assays was estimated by comparison to the composite result and relative to one another. Percent positivity for chlamydia was 5.9 and 1.2% from anal and oropharyngeal specimens, respectively, compared to 4.2 and 4.1% for gonorrhea. Sensitivity for chlamydia detection ranged from 81.0 to 95.1% and 82.8 to 100% for anal and oropharyngeal specimens, respectively. Gonorrhea sensitivity ranged from 85.9 to 99.0% and 74.0 to 100% for anal and oropharyngeal samples, respectively. Specificity estimates were ≥ 98.9% for all assays, organisms, and sample types. Although there was heterogeneity between sensitivity estimates, these assays offer better ability to detect extragenital infections than culture and potential solutions for providing appropriate sexual health care for populations in which these infections are of concern.

BackgroundChlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are extremely common sexually transmitted infections (STIs) that are associated with adverse birth and neonatal outcomes, and the risk of vertical transmission of CT and NG during delivery is high. The majority of CT and NG infections are asymptomatic and missed by the standard of care in most countries (treatment based on symptoms). Thus, it is likely that missed maternal CT and NG infections contribute to preventable adverse health outcomes among women and children globally. This study aims to assess the effectiveness of CT and NG testing for asymptomatic pregnant women to prevent adverse neonatal outcomes, understand the inflammatory response linking CT and NG infections to adverse neonatal outcomes, and conduct an economic analysis of the CT and NG testing intervention.MethodsThe Maduo ("results" in Setswana) is a prospective, cluster-controlled trial in Gaborone, Botswana to compare a near point-of-care CT and NG testing and treatment intervention implemented in "study clinics" with standard antenatal care (World Health Organization-endorsed "syndromic management" strategy based on signs and symptoms without laboratory confirmation) implemented in "standard of care clinics" among asymptomatic pregnant women. The primary outcome is vertical transmission of CT/NG infection. Secondary outcomes include preterm birth (delivery

BackgroundChlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are common sexually transmitted infections (STIs) associated with adverse outcomes, yet most countries do not test and conduct syndromic management, which lacks sensitivity and specificity. Innovations allow for expanded STI testing; however, cost is a barrier.MethodsUsing inputs from a pilot program in Botswana, we developed a model among a hypothetical population of 50,000 pregnant women to compare 1-year costs and outcomes associated with 3 antenatal STI testing strategies: (1) point-of-care, (2) centralized laboratory, and (3) a mixed approach (point of care at high-volume sites, and hubs elsewhere), and syndromic management.ResultsSyndromic management had the lowest delivery cost but was associated with the most infections at delivery, uninfected women treated, CT/NG-related low-birth-weight infants, disability-adjusted life years, and low birth weight hospitalization costs. Point-of-care CT/NG testing would treat and cure the most infections but had the highest delivery cost. Among the testing scenarios, the mixed scenario had the most favorable cost per woman treated and cured ($534/cure). Compared with syndromic management, the mixed approach resulted in a mean incremental cost-effectiveness ratio of $953 per disability-adjusted life years averted, which is cost-effective under World Health Organization's one-time per-capita gross domestic product willingness-to-pay threshold.ConclusionsAs countries consider new technologies to strengthen health services, there is an opportunity to determine how to best deploy resources. Compared with point-of-care, centralized laboratory, and syndromic management, the mixed approach offered the lowest cost per infection averted and is cost-effective if policy makers' willingness to pay is informed by the World Health Organization's gross domestic product/capita threshold.

Based on epidemiology studies, Chlamydia trachomatis has been proposed as a co-factor for human papillomavirus (HPV) in the development of cervical cancer. These two intracellular pathogens have been independently reported to induce the production of extra centrosomes, or centrosome amplification, which is a hallmark of cancer cells. We developed a cell culture model to systematically measure the individual and combined effects of Chlamydia and HPV on the centrosome in the same host cell. We found that C. trachomatis caused centrosome amplification in a greater proportion of cells than HPV and that the effects of the two pathogens on the centrosome were additive. Furthermore, centrosome amplification induced by Chlamydia, but not by HPV, strongly correlated with multinucleation and required progression through mitosis. Our results suggest that C. trachomatis and HPV induce centrosome amplification through different mechanisms, with the chlamydial effect being largely due to a failure in cytokinesis that also results in multinucleation. Our findings provide support for C. trachomatis as a co-factor for HPV in carcinogenesis and offer mechanistic insights into how two infectious agents may cooperate to promote cancer. TAKE AWAYS: • Chlamydia and HPV induce centrosome amplification in an additive manner. • Chlamydia-induced centrosome amplification is linked to host cell multinucleation. • Chlamydia-induced centrosome amplification requires cell cycle progression. • Chlamydia and HPV cause centrosome amplification through different mechanisms. • This study supports Chlamydia as a co-factor for HPV in carcinogenesis.

BackgroundThe World Health Organization (WHO) recommends annual mass azithromycin distribution until districts drop below 5% prevalence of trachomatous inflammation-follicular (TF). Districts with very low TF prevalence may have little or no transmission of the ocular strains of Chlamydia trachomatis that cause trachoma, and additional rounds of mass azithromycin distribution may not be useful. Here, we describe the protocol for a randomized controlled trial designed to evaluate whether mass azithromycin distribution can be stopped prior to the current WHO guidelines.MethodsThe Azithromycin Reduction to Reach Elimination of Trachoma (ARRET) study is a 1:1 community randomized non-inferiority trial designed to evaluate whether mass azithromycin distribution can be stopped in districts with baseline prevalence of TF under 20%. Communities in Maradi, Niger are randomized after baseline assessment either to continued annual mass azithromycin distribution or stopping annual azithromycin distribution over a 3-year period. We will compare the prevalence of ocular C. trachomatis (primary outcome), TF and other clinical signs of trachoma, and serologic markers of trachoma after 3 years. We hypothesize that stopping annual azithromycin distribution will be non-inferior to continued annual azithromycin distributions for all markers of trachoma prevalence and transmission.DiscussionThe results of this trial are anticipated to provide potentially guideline-changing evidence for when mass azithromycin distributions can be stopped in low TF prevalence areas. TRIAL REGISTRATION NUMBER: This study is registered at clinicaltrials.gov ( NCT04185402 ). Registered December 4, 2019; prospectively registered pre-results.

BackgroundPublic health organizations have inconsistent recommendations for screening adolescents and young adults for Chlamydia trachomatis and Neisseria gonorrhoeae infections. Guidelines suggest different combinations of anorectal, pharyngeal, and urogenital testing based on age, sex, and sexual activity. Further evaluation of how identity and behaviors impact the anatomic distribution of C. trachomatis and N. gonorrhoeae infection is needed to optimize future screening practices.MethodsWe assessed the positivity of C. trachomatis and N. gonorrhoeae infections at different anatomic sites in a cohort of at-risk sexually active adolescents and young adults aged 12-24 years in New Orleans, Louisiana and Los Angeles, California. Participants were tested for C. trachomatis and N. gonorrhoeae at 3 sites (anorectum, pharynx, and urethral/cervix) every 4 months using self-collected swabs. We stratified anatomic distributions of infection into 4 gender and sexual behavior categories: (1) cisgender men who have sex with men and transgender women (MSMTW); (2) cisgender heterosexual males; (3) cisgender heterosexual females; and (4) gender minorities assigned female at birth.ResultsWhile three-site testing detected all infections, two-site (anorectum and urethra/cervix) testing identified 92%-100% of C. trachomatis or N. gonorrhoeae infections in participants assigned female at birth and cisgender heterosexual males. For MSMTW, two-site anorectal and pharyngeal testing vs single-site anorectal testing increased the proportion of individuals with either infection from 74% to 93%.ConclusionsSexual behavior and gender identity may influence detection of C. trachomatis and N. gonorrhoeae infections at specific anatomic testing sites. Testing guidelines should incorporate sexual behavior and gender identity.Clinical trials registrationNCT03134833.

BackgroundAlthough molecular testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is highly sensitive, the cost can be prohibitive. Those high costs are amplified when the recommended screening approach is used, which requires separate testing of specimens from 3 anatomic sites (rectal, pharyngeal and urogenital). Although individual molecular testing is standard of care, pooled testing may offer a cost-saving alternative.MethodsUsing the Xpert® CT/NG assay (Cepheid, Sunnyvale, CA) we tested urine, rectal and pharyngeal swabs for CT and NG in a high-risk cohort of participants assigned male at birth who reported sex with other persons who were assigned male at birth. Remnant specimens (0.34 mL from each anatomic site) were combined to perform a single 'pooled' test. We calculated positive and negative percent agreement between the pooled testing results with standard of care Xpert CT/NG test results as the reference.ResultsWe conducted 644 pooled tests. Of those, 598 (92.3%) gave CT and NG results. The CT-positive and -negative percent agreement were 90.1% (95% confidence interval [CI], 80.7-95.9%) and 99.2% (98.1-99.8%), respectively. The NG-positive and -negative percent agreement were 96.2% (95% CI, 86.8-99.5%) and 99.8% (95% CI, 99.0-100%), respectively. Pooled testing identified 4 CT and 1 NG infections that were negative at all anatomic sites by individual testing.ConclusionsThree-site pooled CT and NG testing performs similarly to single anatomic site testing among tests providing a valid result. Future cost analyses should evaluate the cost effectiveness of pooled 3-site testing to determine if such a strategy improves the feasibility and accessibility of molecular sexually transmitted infection testing.

Pelvic inflammatory disease (PID) is a clinical syndrome that has been associated with a wide range of potential causal pathogens. Three broad groups of organisms have been isolated from the genital tract of people with PID: sexually transmitted organisms such as Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, and Trichomonas vaginalis; bacterial vaginosis (BV)-associated species and genera such as Atopobium vaginae, Sneathia, and Megasphaera; and genera and species usually associated with the gastrointestinal or respiratory tracts such as Bacteroides, Escherichia coli, Streptococcus, or Haemophilus influenza. Although PID is often considered to be synonymous with gonorrhea or chlamydia, these pathogens are found in only one quarter to one third of people with PID, suggesting that broader screening and diagnostic and treatment strategies need to be considered to reduce the burden of PID and its associated sequelae.

The obligate intracellular pathogen Chlamydia trachomatis (Ct) is the leading cause of bacterial sexually transmitted infections and blindness globally. To date, Ct urogenital strains are considered tryptophan prototrophs, utilizing indole for tryptophan synthesis within a closed-conformation tetramer comprised of two α (TrpA)- and two β (TrpB)-subunits. In contrast, ocular strains are auxotrophs due to mutations in TrpA, relying on host tryptophan pools for survival. It has been speculated that there is strong selective pressure for urogenital strains to maintain a functional operon. Here, we performed genetic, phylogenetic, and novel functional modeling analyses of 595 geographically diverse Ct ocular, urethral, vaginal, and rectal strains with complete operon sequences. We found that ocular and urogenital, but not lymphogranuloma venereum, TrpA-coding sequences were under positive selection. However, vaginal and urethral strains exhibited greater nucleotide diversity and a higher ratio of nonsynonymous to synonymous substitutions [Pi(a)/Pi(s)] than ocular strains, suggesting a more rapid evolution of beneficial mutations. We also identified nonsynonymous amino acid changes for an ocular isolate with a urogenital backbone in the intergenic region between TrpR and TrpB at the exact binding site for YtgR-the only known iron-dependent transcription factor in Chlamydia-indicating that selective pressure has disabled the response to fluctuating iron levels. In silico effects on protein stability, ligand-binding affinity, and tryptophan repressor (TrpR) affinity for single-stranded DNA (ssDNA) measured by calculating free energy changes (ΔΔG) between Ct reference and mutant tryptophan operon proteins were also analyzed. We found that tryptophan synthase function was likely suboptimal compared to other bacterial tryptophan prototrophs and that a diversity of urogenital strain mutations rendered the synthase nonfunctional or inefficient. The novel mutations identified here affected active sites in an orthosteric manner but also hindered α- and β-subunit allosteric interactions from distant sites, reducing efficiency of the tryptophan synthase. Importantly, strains with mutant proteins were inclined toward energy conservation by exhibiting an altered affinity for their respective ligands compared to reference strains, indicating greater fitness. This is not surprising as l-tryptophan is one of the most energetically costly amino acids to synthesize. Mutations in the tryptophan repressor gene (trpR) among urogenital strains were similarly detrimental to function. Our findings indicate that urogenital strains are evolving more rapidly than previously recognized with mutations that impact tryptophan operon function in a manner that is energetically beneficial, providing a novel host-pathogen evolutionary mechanism for intracellular survival.IMPORTANCEChlamydia trachomatis (Ct) is a major global public health concern causing sexually transmitted and ocular infections affecting over 130 million and 260 million people, respectively. Sequelae include infertility, preterm birth, ectopic pregnancy, and blindness. Ct relies on available host tryptophan pools and/or substrates to synthesize tryptophan to survive. Urogenital strains synthesize tryptophan from indole using their intact tryptophan synthase (TS). Ocular strains contain a trpA frameshift mutation that encodes a truncated TrpA with loss of TS function. We found that TS function is likely suboptimal compared to other tryptophan prototrophs and that urogenital stains contain diverse mutations that render TS nonfunctional/inefficient, evolve more rapidly than previously recognized, and impact operon function in a manner that is energetically beneficial, providing an alternative host-pathogen evolutionary mechanism for intracellular survival. Our research has broad scientific appeal since our approach can be applied to other bacteria that may explain evolution/survival in host-pathogen interactions.

Rapid and precise detection of Chlamydia trachomatis, the leading global cause of sexually transmitted infections (STI), at the point of care (POC) is required for treatment decisions to prevent transmission and sequelae, including pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility, and preterm birth. We developed a rapid POC test (POCT), termed LH-POCT, which uses loop-mediated amplification (LAMP) of nucleic acids. We performed a head-to-head comparison with the Cepheid Xpert CT/NG assay using clinician-collected, deidentified paired vaginal samples from a parent study that consecutively enrolled symptomatic and asymptomatic females over 18 years of age from the Ministry of Health and Medical Services Health Centers in Fiji. Samples were processed by the Xpert CT/NG assay and LH-POCT, blinded to the comparator. Discrepant samples were resolved by quantitative PCR. Deidentified clinical data and tests for Trichomonas vaginalis, Candida, and bacterial vaginosis (BV) were provided. There were a total of 353 samples from 327 females. C. trachomatis positivity was 16.7% (59/353), while the prevalence was 16.82% (55/327) after discrepant resolution. Seven discrepant samples resolved to four false negatives, two false positives, and one true positive for the LH-POCT. The sensitivity of the LH-POCT was 93.65% (95% confidence interval [CI], 84.53% to 98.24%), and specificity was 99.31% (95% CI, 97.53% to 99.92%). Discrepant samples clustered among women with vaginal discharge and/or BV. The prototype LH-POCT workflow has excellent performance, meeting many World Health Organization ASSURED criteria for POC tests, including a sample-to-result time of 35 min. Our LH-POCT holds promise for improving clinical practice to prevent and control C. trachomatis STIs in diverse health care settings globally.

BackgroundData on testing rates and prevalence of and factors associated with genital and extragenital chlamydia and gonorrhea among transgender women with HIV in the United States are limited.MethodsThis retrospective cohort analysis included transgender women living with HIV enrolled in the US Centers for AIDS Research Network of Integrated Clinical Systems cohort between January 2005 and December 2016 with chlamydia or gonorrhea testing performed in HIV clinic. The primary outcome was a positive test result for chlamydia or gonorrhea at urogenital or extragenital (rectal/pharyngeal) sites. Factors associated with infection were examined using logistic regression and generalized estimating equations to account for multiple tests per woman.ResultsAmong 312 transgender women in HIV care, 252 (81%) were tested for chlamydia or gonorrhea at least once. Annual testing rates were low: 23% to 53% at genital sites and 24% to 47% at extragenital sites. A total of 88 infections were detected, and 22% of women (55/252) had at least one positive test result. Most infections occurred at extragenital sites (80% of chlamydia and 82% of gonorrhea positive test results). Factors associated with infection in an adjusted model were as follows: age 18 to 29 years compared with ≥50 years (adjusted odds ratio [aOR], 7.6; 95% confidence interval [CI], 1.8-31.2), CD4 count >350 compared with CD4

Study objectiveProvider misconceptions regarding intrauterine device (IUD) safety for adolescents and young women can unnecessarily limit contraceptive options offered; we sought to evaluate rates of Neisseria gonorrhoeae or Chlamydia trachomatis (GC/CT) diagnoses among young women who adopted IUDs.DesignSecondary analysis of a cluster-randomized provider educational trial.SettingForty US-based reproductive health centers.ParticipantsWe followed 1350 participants for 12 months aged 18-25 years who sought contraceptive care.InterventionsThe parent study assessed the effect of provider training on evidence-based contraceptive counseling.Main outcome measuresWe assessed incidence of GC/CT diagnoses according to IUD use and sexually transmitted infection risk factors using Cox regression modeling and generalized estimating equations.ResultsTwo hundred four participants had GC/CT history at baseline; 103 received a new GC/CT diagnosis over the 12-month follow-up period. IUDs were initiated by 194 participants. Incidence of GC/CT diagnosis was 10.0 per 100 person-years during IUD use vs 8.0 otherwise. In adjusted models, IUD use (adjusted hazard ratio [aHR], 1.31; 95% confidence interval [CI], 0.71-2.40), adolescent age (aHR, 1.28; 95% CI, 0.72-2.27), history of GC/CT (aHR, 1.23; 95% CI, 0.75-2.00), and intervention status (aHR, 1.12; 95% CI, 0.74-1.71) were not associated with GC/CT diagnosis; however, new GC/CT diagnosis rates were significantly higher among individuals who reported multiple partners at baseline (aHR, 2.0; 95% CI, 1.34-2.98).ConclusionIn this young study population with GC/CT history, this use of IUDs was safe and did not lead to increased GC/CT diagnoses. However, results highlighted the importance of dual sexually transmitted infection and pregnancy protection for participants with multiple partners.

BackgroundTimely detection and treatment are important for the control of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. The objective of this study was to measure the performance of the Visby Medical Sexual Health Test, a single-use, point-of-care PCR device.MethodsWomen aged 14 years and older who presented consecutively to ten clinical sites across seven US states were enrolled for a cross-sectional, single-visit study. Patients who consented to participate, and who had not used any exclusionary products in the genital area in the previous 48 h, provided self-collected vaginal swabs for testing with the investigational device. Untrained operators received the specimens and ran the device using the guide provided. Specimens had to be run within 2 h of collection to be considered valid. For comparison, patient-infected status was derived by testing clinician-collected vaginal specimens with the Hologic Aptima Combo 2 Assay and Aptima Trichomonas vaginalis Assay, as well as the BD ProbeTec CT/GC Qx Amplified DNA Assay and BD ProbeTec Trichomonas vaginalis Qx Assay. If the results of those assays did not match, the BD MAX CT/GC/TV was used as a tiebreaker. The primary outcomes were the sensitivity and specificity of the investigational device for the detection of C trachomatis, N gonorrhoeae, and T vaginalis compared with patient-infected status.FindingsBetween Feb 25, 2019, and Jan 6, 2020, 1585 participants aged between 14 years and 80 years (mean 34·8 [SD 14·2]) were enrolled. 1555 participants had tests run with the investigational device, of whom 1532 (98·5%) had a valid result on either the first or repeat test. Among the patients with evaluable results (including a determinate patient-infected status), the device had a sensitivity of 97·6% (95% CI 93·2-99·2) and specificity of 98·3% (97·5-98·9) for C trachomatis (n=1457), sensitivity of 97·4% (86·5-99·5) and specificity of 99·4% (98·9-99·7) for N gonorrhoeae (n=1468), and sensitivity of 99·2% (95·5-99·9) and specificity of 96·9% (95·8-97·7) for T vaginalis (n=1449).InterpretationThis innovative, rapid, easy-to-use, single-use, point-of-care device to detect C trachomatis, N gonorrhoeae, and T vaginalis infections showed excellent sensitivity and specificity, and could represent an important advance in the development of rapid diagnostics for sexually transmitted infections and other infectious diseases.FundingDivision of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases.

Chlamydia trachomatis, an obligately intracellular bacterium, is the most prevalent cause of bacterial sexually transmitted infections (STIs) worldwide. Numbers of U.S. infections of the urogenital tract and rectum have increased annually. Because C. trachomatis is not easily cultured, comparative genomic studies are limited, restricting our understanding of strain diversity and emergence among populations globally. While Agilent SureSelectXT target enrichment RNA bait libraries have been developed for whole-genome enrichment and sequencing of C. trachomatis directly from clinical urine, vaginal, conjunctival, and rectal samples, public access to these libraries is not available. We therefore designed an RNA bait library (34,795 120-mer probes based on 85 genomes, versus 33,619 probes using 74 genomes in a previous one) to augment organism sequencing from clinical samples that can be shared with the scientific community, enabling comparison studies. We describe the library and limit of detection for genome copy input, and we present results of 100% efficiency and high-resolution determination of recombination and identical genomes within vaginal-rectal specimen pairs in women. This workflow provides a robust approach for discerning genomic diversity and advancing our understanding of the molecular epidemiology of contemporary C. trachomatis STIs across sample types, geographic populations, sexual networks, and outbreaks associated with proctitis/proctocolitis among women and men who have sex with men.IMPORTANCEChlamydia trachomatis is an obligate intracellular bacterium that is not easily cultured, which limits our understanding of urogenital and rectal C. trachomatis transmission and impact on morbidity. To provide a publicly available workflow for whole-genome target enrichment and sequencing of C. trachomatis directly from clinical urine, vaginal, conjunctival, and rectal specimens, we developed and report on an RNA bait library to enrich the organism from clinical samples for sequencing. We demonstrate an increased efficiency in the percentage of reads mapping to C. trachomatis and identified recombinant and identical C. trachomatis genomes in paired vaginal-rectal samples from women. Our workflow provides a robust genomic epidemiologic approach to advance our understanding of C. trachomatis strains causing ocular, urogenital, and rectal infections and to explore geo-sexual networks, outbreaks of colorectal infections among women and men who have sex with men, and the role of these strains in morbidity.

BackgroundDiagnostic options to combat the increasing rates of sexually transmitted infections recorded throughout the world increasingly include multiplex assays. Here we describe the estimated sensitivity and specificity of a triplex molecular assay that simultaneously detects Chlamydia trachomatis (CT), Neisseria gonorrhoeae (or gonococci [GC]), and Trichomonas vaginalis (TV).MethodsParticipants (2547 women and 1159 men) were recruited from 12 clinics in the United States. BD CTGCTV2 for BD MAX System assay (CTGCTV2) results were obtained from vaginal and endocervical swabs, endocervical samples in cytology medium, and female and male urine. Results were compared with infection standards that were sample type and pathogen dependent.ResultsFemale specimen sensitivity estimates ranged from 92.7% to 98.4%, 92.9% to 100%, and 86.6% to 100% for CT, GC and TV, respectively. Male urine sensitivity estimates were 96.7%, 99.2%, and 97.9% for CT, GC, and TV, respectively. Specificity estimates were >98.7% for all sample types.ConclusionsBD CTGCTV2 performed well using a variety of sample types. As a true triplex assay, performed using a benchtop instrument, BD CTGCTV2 may be useful in settings where no testing is currently performed and in settings, such as reference laboratories, where testing turnaround time may be several days. Use of this assay at local laboratories may result in greater access to testing and a shorter time to result, which are important steps for improving our ability to combat sexually transmitted infections.

BackgroundPorto Alegre, Brazil, has the highest rates of congenital syphilis and HIV in the country. Other treatable sexually transmitted infections (STIs) are associated with poor pregnancy and neonatal outcomes, but are only diagnosed by syndromic algorithms.MethodsBetween September 2018 and November 2019, we offered all pregnant women clinic-based STI testing for HIV antibody and treponemal antibody (via lateral flow assay rapid tests provided by the Brazilian Government) and for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis (via polymerase chain reaction-based testing provided by Gene Xpert, Sunnyvale, CA) in 10 public prenatal health clinics in Porto Alegre. Participating women answered a brief survey via audio computer-assisted survey instrument regarding demographics, partnerships, and sexual behaviors. All infected individuals received appropriate treatment and referrals.ResultsOf 400 pregnant women recruited, 94 (24%) were diagnosed with an STI, including 2% with HIV, 11% with syphilis, 9% with chlamydia, 1% with gonorrhea, 5% with trichomoniasis, and 3% with more than 1 STI. In our multivariate analysis, younger age (adjusted odds ratio [AOR], 1.1; 95% confidence interval [CI], 1-1.2), being non-White (AOR, 1.8; 95% CI, 1.1-3.1), having less education (AOR, 2; 95% CI, 1.2-3.4), and having a relationship

The Trachoma Control Program in Amhara region, Ethiopia, scaled up the surgery, antibiotics, facial cleanliness, and environmental improvement (SAFE) strategy in all districts starting in 2007. Despite these efforts, many districts still require additional years of SAFE. In 2017, four districts were selected for the assessment of antibody responses against Chlamydia trachomatis antigens and C. trachomatis infection to better understand transmission. Districts with differing endemicity were chosen, whereby one had a previous trachomatous inflammation-follicular (TF) prevalence of ≥ 30% (Andabet), one had a prevalence between 10% and 29.9% (Dera), one had a prevalence between 5% and 10% (Woreta town), and one had a previous TF prevalence of < 5% (Alefa) and had not received antibiotic intervention for 2 years. Survey teams assessed trachoma clinical signs and took conjunctival swabs and dried blood spots (DBS) to measure infection and antibody responses. Trachomatous inflammation-follicular prevalence among children aged 1-9 years was 37.0% (95% CI: 31.1-43.3) for Andabet, 14.7% (95% CI: 10.0-20.5) for Dera, and < 5% for Woreta town and Alefa. Chlamydia trachomatis infection was only detected in Andabet (11.3%). Within these districts, 2,195 children provided DBS. The prevalence of antibody responses to the antigen Pgp3 was 36.9% (95% CI: 29.0-45.6%) for Andabet, 11.3% (95% CI: 5.9-20.6%) for Dera, and < 5% for Woreta town and Alefa. Seroconversion rate for Pgp3 in Andabet was 0.094 (95% CI: 0.069-0.128) events per year. In Andabet district, where SAFE implementation has occurred for 11 years, the antibody data support the finding of persistently high levels of trachoma transmission.

Multiplex bead assays (MBAs) for serologic testing have become more prevalent in public health surveys, but few studies have assessed their test performance. As part of a trachoma study conducted in a rural part of Ethiopia in 2016, dried blood spots (DBS) were collected from a random sample of 393 children aged 0 to 9 years, with at least two separate 6-mm DBS collected on a filter card. Samples eluted from DBS were processed using an MBA on the Luminex platform for antibodies against 13 antigens of nine infectious organisms: Chlamydia trachomatis, Vibrio cholera, enterotoxigenic Escherichia coli, Cryptosporidium parvum, Entamoeba histolytica, Camplyobacter jejuni, Salmonella typhimurium Group B, Salmonella enteritidis Group D, and Giardia lamblia. Two separate DBS from each child were processed. The first DBS was run a single time, with the MBA set to read 100 beads per well. The second DBS was run twice, first at 100 beads per well and then at 50 beads per well. Results were expressed as the median fluorescence intensity minus background (MFI-BG), and classified as seropositive or seronegative according to external standards. Agreement between the three runs was high, with intraclass correlation coefficients of > 0.85 for the two Salmonella antibody responses and > 0.95 for the other 11 antibody responses. Agreement was also high for the dichotomous seropositivity indicators, with Cohen's kappa statistics exceeding 0.87 for each antibody assay. These results suggest that serologic testing on the Luminex platform had strong test performance characteristics for analyzing antibodies using DBS.

Chlamydial trachomatis infection has been associated with adverse pregnancy and neonatal outcomes such as premature rupture of membranes, preterm birth, low birth weight, conjunctivitis, and pneumonia in infants. This review evaluates existing literature to determine potential benefits of antenatal screening and treatment of C. trachomatis in preventing adverse outcomes. A literature search revealed 1824 studies with 156 full-text articles reviewed. Fifteen studies were selected after fulfilling inclusion criteria. Eight studies focused on chlamydial screening and treatment to prevent adverse pregnancy outcomes such as premature rupture of membranes, preterm birth, low birth weight, growth restriction leading to small for gestational age infants, and neonatal death. Seven studies focused on the effects of chlamydial screening and treatment on adverse infant outcomes such as chlamydial infection including positive mucosal cultures, pneumonia, and conjunctivitis. Given the heterogeneity of those studies, this focused review was exclusively qualitative in nature. When viewed collectively, 13 of 15 studies provided some degree of support that antenatal chlamydial screening and treatment interventions may lead to decreased adverse pregnancy and infant outcomes. However, notable limitations of these individual studies also highlight the need for further, updated research in this area, particularly from low and middle-income settings.

The World Health Organization (WHO) recommends continuing azithromycin mass drug administration (MDA) for trachoma until endemic regions drop below 5% prevalence of active trachoma in children aged 1-9 years. Azithromycin targets the ocular strains of Chlamydia trachomatis that cause trachoma. Regions with low prevalence of active trachoma may have little if any ocular chlamydia, and, thus, may not benefit from azithromycin treatment. Understanding what happens to active trachoma and ocular chlamydia prevalence after stopping azithromycin MDA may improve future treatment decisions. We systematically reviewed published evidence for community prevalence of both active trachoma and ocular chlamydia after cessation of azithromycin distribution. We searched electronic databases for all peer-reviewed studies published before May 2020 that included at least 2 post-MDA surveillance surveys of ocular chlamydia and/or the active trachoma marker, trachomatous inflammation-follicular (TF) prevalence. We assessed trends in the prevalence of both indicators over time after stopping azithromycin MDA. Of 140 identified studies, 21 met inclusion criteria and were used for qualitative synthesis. Post-MDA, we found a gradual increase in ocular chlamydia infection prevalence over time, while TF prevalence generally gradually declined. Ocular chlamydia infection may be a better measurement tool compared to TF for detecting trachoma recrudescence in communities after stopping azithromycin MDA. These findings may guide future trachoma treatment and surveillance efforts.

To identify immunodominant antigens that elicit a humoral immune response following a primary and a secondary genital infection, rhesus monkeys were inoculated cervically with Chlamydia trachomatis serovar D. Serum samples were collected and probed with a protein microarray expressing 864/894 (96.4%) of the open reading frames of the C. trachomatis serovar D genome. The antibody response to the primary infection was analyzed in 72 serum samples from 12 inoculated monkeys. The following criteria were utilized to identify immunodominant antigens: proteins found to be recognized by at least 75% (9/12) of the infected monkeys with at least 15% elevations in signal intensity from week 0 to week 8 post infection. All infected monkeys developed Chlamydia specific serum antibodies. Eight proteins satisfied the selection criteria for immunodominant antigens: CT242 (OmpH-like protein), CT541 (mip), CT681 (ompA), CT381 (artJ), CT443 (omcB), CT119 (incA), CT486 (fliY), and CT110 (groEL). Of these, three antigens, CT119, CT486 and CT381, were not previously identified as immunodominant antigens using non-human primate sera. Following the secondary infection, the antibody responses to the eight immunodominant antigens were analyzed and found to be quite different in intensity and duration to the primary infection. In conclusion, these eight immunodominant antigens can now be tested for their ability to identify individuals with a primary C. trachomatis genital infection and to design vaccine strategies to protect against a primary infection with this pathogen.

BackgroundThe COVID-19 pandemic illuminated the benefits of telemedicine. Self-collected specimens are a promising alternative to clinician-collected specimens when in-person testing is not feasible. In this study, we assessed the adequacy of self-collected pharyngeal and rectal specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae among individuals undergoing chlamydia and gonorrhea screening.MethodsWe used data from a large cohort study that included male and female adolescents between the ages of 12-24 years. We considered self-collected specimens adequate for clinical use if the human synthase gene (a control target of the assay) was detected in the specimen.ResultsIn total, 2,458 specimens were included in the analysis. The human synthase gene was detected in 99.2% (2,439/2,458) of all self-collected specimens, 99.5% (1,108/1,114) of the pharyngeal specimens, and 99.0% (1,331/1,344) of the rectal specimens.ConclusionSelf-collected pharyngeal and rectal specimens demonstrated a very high proportion of human gene presence, suggesting that self-collection was accurate. A limitation of this study is that the sample adequacy control detects the presence or absence of the human hydroxymethylbilane synthase gene, but it does not indicate the specific anatomic origin of the human hydroxymethylbilane synthase gene. Self-collected specimens may be an appropriate alternative to clinician-collected specimens.

Chlamydia trachomatis is the most common bacterial sexually-transmitted pathogen for which there is no vaccine. We previously demonstrated that the degree of phosphate substitution in an aluminum hydroxide adjuvant in a TLR-4-based C. trachomatis serovar E (Ser E) recombinant major outer membrane protein (rMOMP) formulation had an impact on the induced antibody titers and IFN-γ levels. Here, we have extended these observations using outbreed CD-1 mice immunized with C. trachomatis Ser E rMOMP formulations to evaluate the impact on bacterial challenge. The results confirmed that the rMOMP vaccine containing the adjuvant with the highest phosphate substitution induced the highest neutralizing antibody titers while the formulation with the lowest phosphate substitution induced the highest IFN-γ production. The most robust protection was observed in mice vaccinated with the formulation containing the adjuvant with the lowest phosphate substitution, as shown by the number of mice with positive vaginal cultures, number of positive cultures and number of C. trachomatis inclusion forming units recovered. This is the first report showing that vaccination of an outbred strain of mice with rMOMP induces protection against a vaginal challenge with C. trachomatis.

The transmission of trachoma, caused by repeat infections with Chlamydia trachomatis, and many enteropathogens are linked to water quantity. We hypothesized that children living further from a water source would have higher exposure to C. trachomatis and enteric pathogens as determined by antibody responses. We used a multiplex bead assay to measure IgG antibody responses to C. trachomatis, Giardia intestinalis, Cryptosporidium parvum, Entamoeba histolytica, Salmonella enterica, Campylobacter jejuni, enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae in eluted dried blood spots collected from 2267 children ages 0-9 years in 40 communities in rural Ethiopia in 2016. Linear distance from the child's house to the nearest water source was calculated. We derived seroprevalence cutoffs using external negative control populations, if available, or by fitting finite mixture models. We used targeted maximum likelihood estimation to estimate differences in seroprevalence according to distance to the nearest water source. Seroprevalence among 1-9-year-olds was 43% for C. trachomatis, 28% for S. enterica, 70% for E. histolytica, 54% for G. intestinalis, 96% for C. jejuni, 76% for ETEC and 94% for C. parvum. Seroprevalence increased with age for all pathogens. Median distance to the nearest water source was 473 meters (IQR 268, 719). Children living furthest from a water source had a 12% (95% CI: 2.6, 21.6) higher seroprevalence of S. enterica and a 12.7% (95% CI: 2.9, 22.6) higher seroprevalence of G. intestinalis compared to children living nearest. Seroprevalence for C. trachomatis and enteropathogens was high, with marked increases for most enteropathogens in the first two years of life. Children living further from a water source had higher seroprevalence of S. enterica and G. intestinalis indicating that improving access to water in the Ethiopia's Amhara region may reduce exposure to these enteropathogens in young children.

Nucleic acid amplification tests are increasingly used to detect ocular chlamydia infection in trachoma research and programs. To evaluate the reliability of Chlamydia trachomatis detection by the Abbott RealTime CT/NG assay (Abbott Molecular, Inc., Des Plaines, IL) on the m2000 platform, three conjunctival samples were collected from each of 200 children aged 0-9 years in Ethiopia: two from the right eye and one from the left eye. Four aliquots were processed for each child: two from the first right eye sample, one from the second right eye sample, and one from the left eye sample. Sixty-nine swabs were processed in a U.S. laboratory and 131 in an Ethiopian laboratory. Intra-class correlation coefficients (ICCs) were high when comparing two aliquots from the same swab (ICC ranged from 0.96 to 0.99), two separate swabs from the right eye (0.89-0.91), and one right and one left eye swab (0.87-0.89), indicating reliable chlamydial load assessment across different samples and laboratory settings.

We examined whether the implementation of the Centers for Disease Control and Prevention's recommended screening of Chlamydia trachomatis/Neisseria gonorrhoeae with proactive follow-up among high-risk youth recruited from community and clinic settings reduced future C. trachomatis/N. gonorrhoeae diagnoses. After the Centers for Disease Control and Prevention's recommendations demonstrated a 41% decline in sexually transmitted infections; 3 tests in 1 year resulted in a 10% decline.

PurposeAnnual mass azithromycin distribution significantly reduces the prevalence of ocular Chlamydia trachomatis, the causative organism of trachoma. However, in some areas a decade or more of treatment has not controlled infection. Here, we compared multiple treatment arms from a community-randomized trial to evaluate whether increasing frequency of azithromycin distribution decreases prevalence in the short term.MethodsSeventy-two communities in Goncha Siso Enesie woreda in the Amhara region of Northern Ethiopia were randomized to 1 of 6 azithromycin distribution strategies: (1) delayed, (2) annual, (3) biannual, (4) quarterly to children only, (5) biennial, or (6) biennial plus latrine promotion. We analyzed data from the 60 communities in the delayed, annual, biannual, quarterly, and biennial distribution arms at the 12-month study visit. Communities in the annual and biennial distribution arm were combined, as they each had a single distribution before any 12-month retreatment. We assessed the effect of increased frequency of azithromycin distribution on ocular chlamydia prevalence.ResultsOcular chlamydia prevalence was significantly different across azithromycin distribution frequency in children (P < .0001) and adults (P

Chlamydia trachomatis and Neisseria gonorrhoeae infections in the rectum and pharynx are important extragenital reservoirs of infection. Few assays approved by the US Food and Drug Administration are commercially available to diagnose pharyngeal or rectal infections. The current study reports on the analytical performance of the Abbott RealTime CT/NG assay, including the limit of detection, inclusivity, and analytical specificity for C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens. The limit of detection was performed using known concentrations of organisms, elementary bodies per milliliter (EB/mL) for C. trachomatis and colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae, in clinical rectal and pharyngeal swab matrices. Inclusivity was performed against 12 serovars of C. trachomatis and seven strains of N. gonorrhoeae. The analytical specificity was performed using 28 different bacteria and viruses. The limit of detection for C. trachomatis was 2.56 EB/mL in pharyngeal specimens and 12.8 EB/mL in rectal specimens. The limit of detection for N. gonorrhoeae was 0.0256 CFU/mL for both pharyngeal and rectal specimens. The inclusivity and analytical specificity were 100% for both rectal and pharyngeal specimens. These analytical performance data demonstrate that the Abbott CT/NG RealTime assay is an accurate, sensitive, and specific assay in rectal and pharyngeal specimens, supporting the potential of the assay for detection of rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections.

BACKGROUND:After approximately 5 years of SAFE (surgery, antibiotics, facial cleanliness, environmental improvement) interventions for trachoma, hyperendemic (trachomatous inflammation-follicular (TF) ≥30%) districts remained in Amhara, Ethiopia. This study's aim was to characterize the epidemiology of Chlamydia trachomatis (Ct) infection and load among pre-school aged children living under the SAFE strategy. METHODS:Conjunctival swabs from a population-based sample of children aged 1-5 years collected between 2011 and 2015 were assayed to provide Ct infection data from 4 endemic zones (comprised of 58 districts). Ct load was determined using a calibration curve. Children were graded for TF and trachomatous inflammation-intense (TI). RESULTS:7,441 children were swabbed in 4 zones. TF and TI prevalence were 39.9% (95% confidence Interval [CI]: 37.5%, 42.4%), and 9.2% (95% CI: 8.1%, 10.3%) respectively. Ct infection prevalence was 6.0% (95% CI: 5.0%, 7.2%). Infection was highest among children aged 2 to 4 years (6.6%-7.0%). Approximately 10% of infection occurred among children aged 1 year. Ct load decreased with age (P = 0.002), with the highest loads observed in children aged 1 year (P = 0.01) vs. aged 5 years. Participants with TF (P = 0.20) and TI (P

The obligate intracellular bacterium Chlamydia trachomatis causes the most prevalent bacterial sexually transmitted infection worldwide. CD4 T cells play a central role in the protective immunity against Chlamydia female reproductive tract (FRT) infection, while B cells are thought to be dispensable for resolution of primary Chlamydia infection in mouse models. We recently reported an unexpected requirement of B cells in local Chlamydia-specific CD4 T-cell priming and bacterial containment within the FRT. Here, we sought to tackle the precise effector function of B cells during Chlamydia primary infection. Using mixed bone marrow chimeras that lack B-cell-dependent Ag presentation (MHCIIB-/- ) or devoid of circulating antibodies (AID-/- × μS-/- ), we show that Chlamydia-specific CD4 T-cell expansion does not rely on Ag presentation by B cells. Importantly, we demonstrate that antibody, but not B-cell-dependent Ag presentation, is required for preventing systemic bacterial dissemination following Chlamydia FRT infection.

Prenatal Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) infections are associated with adverse birth outcomes. As rapid diagnostic tests become available, it is important to evaluate prenatal sexually transmitted infection (STI) prevalence, as well as the acceptability and feasibility of prenatal screening programs. We recruited 371 pregnant women from four clinics in Kisantu Health Zone, Democratic Republic of Congo (DRC) from October 2016 to March 2017. Trained clinicians collected cervical swabs, and samples were tested by nucleic acid amplification for CT, NG, and TV using a GeneXpert® system. Those testing positive for an STI were treated and asked to return after 4–8 weeks for tests-of-cure. Screening for STIs was widely accepted (99%). STI prevalence at baseline was: CT, 3.2%; NG, 1.5%; and TV, 14%; treatment completion was 97%. Symptoms were reported among 34% of STI-positive women at baseline, compared with 37% of STI-negative women. Upon first test-of-cure, 100% of returning women were cured of CT (n= 10) and NG (n= 5), but only 47% were cured of TV. This study demonstrates the feasibility of implementing diagnostic STI testing for case detection and treatment among expectant mothers in DRC, with implications for maternal and birth outcomes.

We characterized the composition and structure of the vaginal microbiota in a cohort of 149 women with genital Chlamydia trachomatis infection at baseline who were followed quarterly for 9 months after antibiotic treatment. At time of diagnosis, the vaginal microbiota was dominated by Lactobacillus iners or a diverse array of bacterial vaginosis-associated bacteria including Gardnerella vaginalis. Interestingly, L. iners-dominated communities were most common after azithromycin treatment (1 g monodose), consistent with the observed relative resistance of L. iners to azithromycin. Lactobacillus iners-dominated communities have been associated with increased risk of C. trachomatis infection, suggesting that the impact of antibiotic treatment on the vaginal microbiota could favor reinfections. These results provide support for the dual need to account for the potential perturbing effect(s) of antibiotic treatment on the vaginal microbiota, and to develop strategies to protect and restore optimal vaginal microbiota.

BackgroundChlamydia trachomatis is the most common bacterial sexually transmitted infection worldwide with some of the highest prevalence rates among Pacific Island Countries where syndromic management is practiced. However, little is known about the true prevalence and risk indicators for infection among neglected populations in these countries that suffer from health disparities.Methodology/principal findingsConsecutive sampling was used to enroll sexually active females, aged 18-40 years, attending 12 Fijian Ministry of Health and Medical Services Health Centers and outreach locations from February to December, 2018. A Behavioral Surveillance Survey was administered to assess risk indicators for infection. Signs and symptoms were recorded, and vaginal swabs were tested for C. trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Candida and bacterial vaginosis. Bivariate and multivariate logistic regression analyses were performed using R-Studio. Of 577 participants, 103 (17.85%) were infected with C. trachomatis of whom 80% were asymptomatic and only 11 met criteria for syndromic management; 38.8% of infected women were 18-24 years old with a prevalence of 30.5%. 91.7% of participants intermittently or did not use condoms. C. trachomatis infection was associated with iTaukei ethnicity (OR 21.41 [95% CI: 6.38-133.53]); two lifetime partners (OR 2.12 [95% CI: 1.08-4.18]); and N. gonorrhoeae co-infection (OR 9.56 [95% CI: 3.67-28.15]) in multivariate analyses.ConclusionsA disproportionately high burden of C. trachomatis is present among young asymptomatic women in Fiji of iTaukei ethnicity despite the low number of lifetime partners. Syndromic management and lack of barrier contraceptives contribute to hyperendemic levels. Strategic STI education and screening of at-risk adolescents, young women, and their partner(s) with appropriate treatment are urgently needed to control the epidemic.

BackgroundChlamydia trachomatis is the most common sexually transmitted bacterial pathogen worldwide. Here, we determined the ability of a C. trachomatis recombinant major outer membrane protein (rMOMP) vaccine to elicit cross-serogroup protection.MethodsFemale C3H/HeN mice were vaccinated by mucosal and systemic routes with C. trachomatis serovar D (UW-3/Cx) rMOMP and challenged in the ovarian bursa with serovars D (UW-3/Cx), D (UCI-96/Cx), E (IOL-43), or F (N.I.1). CpG-1826 and Montanide ISA 720 were used as adjuvants.ResultsImmune responses following vaccination were more robust against the most closely related serovars. Following a genital challenge (as determined by number of mice with positive vaginal cultures, number of positive cultures, number of inclusion forming units recovered, and number of days with positive cultures) mice challenged with C. trachomatis serovars of the same complex were protected but not those challenged with serovar F (N.I.1) from a different subcomplex. Females were caged with male mice. Based on fertility rates, number of embryos, and hydrosalpinx formation, vaccinated mice were protected against challenges with serovars D (UW-3/Cx), D (UCI-96/Cx), and E (IOL-43) but not F (N.I.1).ConclusionsThis is the first subunit vaccine shown to protect mice against infection, pathology, and infertility caused by different C. trachomatis serovars.

BackgroundGay, bisexual, transgender, and homeless youth are at risk of sexually transmitted infections. As part of an adolescent human immunodeficiency virus prevention study, we provided same-day Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing and treatment. We aimed to evaluate the feasibility and effectiveness of same-day CT and NG treatment on the proportion of participants receiving timely treatment.MethodsWe recruited adolescents with high sexual risk behaviors aged 12 to 24 years from homeless shelters, lesbian, gay, bisexual, and transgender organizations, and community health centers in Los Angeles, California, and New Orleans, Louisiana from May 2017 to June 2019. Initially, participants were offered point-of-care pharyngeal, rectal, and urethral/vaginal CT and NG testing and referral to another clinic for treatment. After March 2018 in Los Angeles and November 2018 in New Orleans, we provided same-day treatment (and partner treatment packs) for study participants. We measured the proportion of participants who received same-day treatment and the median time to treatment. We collected frequency of partner treatment and any reported adverse treatment-related events.ResultsThe proportion of participants receiving same-day CT and NG treatment increased from 3.6% (5/140) to 21.1% (20/95; Δ17.5%; 95% confidence interval, 9.2%-26.9%) after implementation of same-day testing and treatment. The median time to treatment decreased from 18.5 to 3 days. Overall, 36 participants took a total of 48 partner treatment packs. There were no reported treatment-related adverse events.ConclusionsProviding sexually transmitted infection treatment to adolescents at the same visit as testing is feasible and safe, and can increase the proportion of individuals receiving timely treatment.

The current study was designed to evaluate the pathogenesis, pathology and immune response of female genital tract infection with Chlamydia trachomatis L2c, the most recently discovered lymphogranuloma venereum strain, using a porcine model of sexually transmitted infections. Pigs were mock infected, infected once or infected and re-infected intravaginally, and samples were obtained for chlamydial culture, gross and microscopic pathology, and humoral and cell-mediated immunity. Intravaginal inoculation of pigs with this bacterium resulted in an infection that was confined to the urogenital tract, where inflammation and pathology were caused that resembled what is seen in human infection. Re-infection resulted in more severe gross pathology than primary infection, and chlamydial colonization of the urogenital tract was similar for primary infected and re-infected pigs. This indicates that primary infection failed to induce protective immune responses against re-infection. Indeed, the proliferative responses of mononuclear cells from blood and lymphoid tissues to C. trachomatis strain L2c were never statistically different among groups, suggesting that C. trachomatis-specific lymphocytes were not generated following infection or re-infection. Nevertheless, anti-chlamydial antibodies were elicited in sera and vaginal secretions after primary infection and re-infection, clearly resulting in a secondary systemic and mucosal antibody response. While primary infection did not protect against reinfection, the porcine model is relevant for evaluating immune and pathogenic responses for emerging and known C. trachomatis strains to advance drug and/or vaccine development in humans.