Sexually transmitted coinfections among at-risk HIV-positive MSM: implications for optimal preemptive treatment.

Background: Concurrent sexually transmitted infections (STIs) are common in sexually active populations. We aimed to estimate the prevalence and coinfection rates of bacterial STIs among sexually active, HIV-positive men who have sex with men (MSM), and to assess the potential benefits of different combination treatment regimens in managing concurrent bacterial STIs. Methods: From September 2021 to September 2023, HIV-positive MSM underwent STI testing when they had symptoms suggestive of STIs or recently acquired hepatitis C virus (HCV) infection or early syphilis. The oral rinse, rectal swab, and urethral swab specimens were tested for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma spp., Ureaplasma spp., and Trichomonas vaginalis with the use of multiplex real-time polymerase-chain-reaction assays. The estimated coinfection rates were used to evaluate the benefits of different combination treatment regimens for managing coinfections. Results: During the study period, 535 participants (median age, 37 years; and CD4 count, 615 cells/mm3) were enrolled. On their first visits, at least one bacterial pathogen was detected in 57.9% and concomitant bacterial infections were found in 32.9% of the participants. The most commonly identified pathogen was U. urealyticum (36.3%), followed by C. trachomatis (22.8%), and N. gonorrhoeae (19.8%). The factors associated with any bacterial STIs included older age (per 1-year increase, adjusted odds ratio [AOR], 0.97; 95% confidence interval [CI], 0.95-1.00), early syphilis (AOR, 1.87; 95% CI, 1.22-2.84), and having more than 5 sex partners in the preceding 3 months (AOR, 2.08, 95% CI, 1.07-4.06). A combination therapy of benzathine penicillin G with a 7-day course of doxycycline could simultaneously treat 27.1% of C. trachomatis coinfections in participants with early syphilis, while a combination therapy of ceftriaxone with doxycycline could simultaneously treat 40.6% of chlamydial coinfections in participants with gonorrhea. Conclusion: Bacterial STIs were prevalent and concomitant infections were not uncommon among sexually active, HIV-positive MSM, supporting regular screening for bacterial STIs. The effectiveness of preemptive use of doxycycline as combination therapy for concurrent STIs warrants more investigations.

Evaluation of a new CT/NG/TV/MG Real-Time PCR Kit (Vircell) versus the Allplex STI Essential Assay (Seegene) for the diagnosis of sexually transmitted infections.

Sexually transmitted infections (STI) are a public health problem. Real-time PCR assays are the most sensitive test for screening and diagnosis of these infections. The aim of this study was to evaluate a new CT/NG/TV/MG Real-Time PCR (RT-PCR) kit (Vircell) for the detection of Chamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis for the diagnosis of sexual transmitted infections using the Allplex STI Essential Assay (Seegene) as the reference's method. A total of 497 samples from different anatomical sites (endocervical, urethral, rectal, pharyngeal and urine) were analysed from October 2022 to February 2023. A total of 108 (21.73 %) and 106 (21.33 %) positive samples were found for any of the assays used. The most commonly detected pathogen was N. gonorrhoeae (52 samples; 10.46 %), and the least commonly detected was T. vaginalis (three samples; 0.60 %). The anatomical site with the highest prevalence of micro-organisms was a non-urogenital site, the pharynx (26 positive samples; 5.23 %). Using the Allplex STI Essential Assay (Seegene) as the reference method, the diagnosis performance showed that the average specificity of CT/NG/TV/MG RT-PCR Kit (Vircell) was 99.84 % and the sensitivity was 99.53 %. The overall concordance was k=0.98 (CI95 %; 0.96-1). In conclusion, the CT/NG/TV/MG RT-PCR Kit (Vircell) assay shows a good sensitivity and specificity and constitutes a promising and additional alternative to routine procedures for distinct types of clinical specimen in diagnosis STI.

"The blinding disease". The history of trachoma in Italians between the 19th and 20th centuries: colonial or national blindness?

Trachoma is one of the oldest known causes of blindness in humans and it is caused by the intracellular Gram-negative bacterium Chlamydia trachomatis serovars A, B, Ba and C. Its transmission has historically been related to poorness, overcrowded housing and scarce hygiene. We have traced the history of trachoma in Italy in the 19th and 20th centuries, among people living in Italy, those who immigrated to America and the population in the colonies, with a focus on Libya (1912-1943). Trachoma knowledge and perception in Italy and in its colonies was ambiguous during the 19th and 20th centuries. Trachoma was responsible for a great morbidity on both sides of the Mediterranean, in Italy as well as in Libya. Trachoma is still one of the leading infectious causes of preventable blindness worldwide and it was widespread in Italy and the Italian colonies in the first half of the last century.

High burden of human papillomavirus infection among men in Guangzhou, South China: Implications for HPV vaccination strategies.

The epidemiological and clinical aspects of Human Papillomavirus (HPV) infection in women have been extensively studied. However, there is a lack of information regarding HPV characteristics in males. In this study, we conducted a retrospective and observational study of 3737 consecutive male individuals attending outpatient clinics of Guangdong Women and Children Hospital from 2012 to 2023 in Guangzhou, South China, to determine the age- and genotype-specific prevalence of HPV in men. The results showed the overall prevalence of HPV among men was 42.15% (1575/3737), with variations ranging from 29.55% to 81.31% across distinct diagnostic populations. Low-risk HPV6 (15.47%), HPV11 (8.94%), and high-risk HPV52 (5.51%) were the most common types. The annual HPV prevalence decreased significantly (Z = -3.882, p < .001), ranging from 31.44% to 52.90%. 28.77% (1075/3737) of men manifested infection with a singular HPV type, predominantly identified as a low-risk type. The age-specific distribution of HPV infections revealed distinctive peaks in the < 25 y age group (47.60%, 208/437) and the 40-44 y age group (44.51%, 154/346). Notably, the positive rate of Chlamydia trachomatis was significantly higher among HPV-positive individuals in comparison to HPV-negatives (16.14% vs. 11.25%, p < .05). Our findings reveal a substantial prevalence of HPV infection among outpatient men in Guangzhou, South China. It is recommended to consider the inclusion of HPV vaccination for adolescent males in national immunization schedules, once an adequate supply of vaccines is accessible.

Screening for Chlamydia and Gonorrhea in Youth Correctional Facilities, Utah, USA.

We reviewed data obtained in October 2021-May 2023 from youth who reported a history of sexual activity upon admission to 1 of 12 juvenile justice facilities in Utah, USA, that offered screening for Chlamydia trachomatis and Neisseria gonorrhoeae. Urinalysis revealed C. trachomatis positivity of 10.77%, N. gonorrhoeae positivity of 1.08%, and coinfection C. trachomatis N. gonorrhoeae) of 0.90%. Prevalence of infection was similar for youths in rural and urban facilities. A total of 12.01% of those identifying as male and 14.01% of those identifying as female tested positive for C. trachomatis, N. gonorrhoeae, or coinfection. Of young adults who tested positive, 74.65% received their results while incarcerated, all of whom accepted treatment. Our research underscores the feasibility of providing prompt C. trachomatis/N. gonorrhoeae screening and treatment in juvenile correctional facilities. The pervasiveness of infection emphasizes the urgent need for early identification and treatment for C. trachomatis and N. gonorrhoeae in incarcerated youth nationwide.

Characterization of genital chlamydia trachomatis infection among women attending infertility and gynecology clinics in Hunan, China.

BACKGROUND: Genital infection with Chlamydia trachomatis (C. trachomatis) is a major public health issue worldwide. It can lead to cervicitis, urethritis, and infertility. This study was conducted to determine the characteristics of genital C. trachomatis infection among women attending to the infertility and gynecology clinics. METHODS: Endocervical swabs were collected from 8,221 women for C. trachomatis nucleotide screening and genotyping, while serum samples were collected for C. trachomatis pgp3 antibody determination using luciferase immunosorbent assays. RESULTS: High C. trachomatis DNA prevalence (3.76%) and seroprevalence (47.46%) rates were found, with genotype E (27.5%) being the most prevalent. C. trachomatis omp1 sense mutation was associated with cervical intraepithelial neoplasia (CIN) (odds ratio [OR] = 6.033, 95% confidence interval [CI] = 1.219-39.185, p = 0.045). No significant differences in C. trachomatis seroprevalence rates were observed between women with detectable C. trachomatis DNA in the infertility and routine physical examination groups (86.67% vs. 95%, p > 0.05); however, among women with negative C. trachomatis DNA, the former group had a markedly higher seroprevalence than the latter group (56.74% vs. 20.17%, p < 0.001). C. trachomatis DNA, but not pgp3 antibody, was significantly associated with CIN (OR = 4.087, 95% CI = 2.284-7.315, p < 0.001). CONCLUSION: Our results revealed a high prevalence, particularly seroprevalence, of C. trachomatis among women with infertility. Furthermore, we found an association between C. trachomatis omp1 sense mutations and CIN. Therefore, C. trachomatis serves as a risk factor for CIN.

Chlamydia trachomatis seroassays used in epidemiologic research: a narrative review and practical considerations.

Chlamydia trachomatis (CT) is a sexually transmitted infection that can lead to adverse reproductive health outcomes. CT prevalence estimates are primarily derived from screening using nucleic acid amplification tests (NAATs). However, screening guidelines in the United States only include particular subpopulations, and NAATs only detect current infections. In contrast, seroassays identify past CT infections which are important for understanding the public health impacts of CT, including pelvic inflammatory disease and tubal factor infertility. Older seroassays have been plagued by low sensitivity and specificity and have not been validated using a consistent reference measure, making it challenging to compare studies, define the epidemiology of CT and determine the effectiveness of control programs. Newer seroassays have better performance characteristics. This narrative review summarizes the "state of the science" for CT seroassays that have been applied in epidemiologic studies and provides practical considerations for interpreting the literature and employing seroassays in future research.

Seroprevalence of sexually transmitted infections over 44 years - A cross-sectional study in Sweden.

BACKGROUND: Sexually transmitted infections (STIs) may cause substantial individual suffering and a large economic burden for society. This study examined the seroprevalence of Chlamydia trachomatis, Mycoplasma genitalium, herpes simplex virus (HSV) types 1 and 2, and several human papillomaviruses (HPV) in the Swedish population over time. METHODS: The study population consisted of 30-year-old women attending maternity care, and 50 year-old men and women attending health check-ups, from 1975 to 2018. Antibody status was determined by multiplex serology and quantified using median reporter fluorescence intensity (MFI). RESULTS: A total of 891 samples were analysed (519 from 30-year-old women, 186 from 50 year-old women and 186 from 50 year-old men). Of these, 41.5% showed seropositivity for Chlamydia trachomatis, 16.7% for Mycoplasma genitalium, 70.5% for HSV-1, 14.9% for HSV-2, 13.2% for high-risk HPV, and 8.3% for low-risk HPV. Seropositivity for Mycoplasma genitalium, HSV-1 and especially Chlamydia trachomatis decreased over time. CONCLUSIONS: There was a decrease over time in Chlamydia trachomatis seroprevalence, probably due to contact tracing, testing and early treatment; this might also have affected Mycoplasma genitalium seroprevalence. Despite the reduction, seroprevalences are still high, so continued and new efforts to reduce STI incidence are essential.

Screening of single nucleotide polymorphism in matrix metalloproteinase-2 (MMP2) and tetraspanin CD63 genes in Chlamydia trachomatis-infected tubal ectopic pregnancy patients.

OBJECTIVE: Tubal ectopic pregnancy (EP) is a leading cause of maternal morbidity and mortality. Studies have suggested that infection-induced inflammatory responses are major risk factors for EP. The aim of the present study was to find an association between MMP2 and CD63 gene variants and risk of EP during Chlamydia trachomatis infection in an Indian population. METHODS: Fallopian tube samples of 120 EP and 120 tubal ligation women were collected. C. trachomatis was detected by PCR. The genotyping of MMP2 (rs17859882 G/T, rs7201A/C) and CD63(rs2231464 C/T, rs376086542 A/G) gene variants was done by qualitative real-time PCR using allelic discrimination method (VIC- and FAM-labeled). RESULTS: The frequency of GG or GT genotype of MMP2 G/T polymorphism (rs17859882) was 66.6% in infected EP and 36.7% in uninfected EP and 22% in tubal ligation controls (P < 0.0001), while the frequency of AC or CC genotype of MMP2 A/C polymorphism (rs7201) was 66.6% in infected EP and 20.6% in uninfected EP and 13.5% in tubal ligation controls (P < 0.0001). The frequency of CT or TT genotype of CD63 C/T polymorphism (rs2231464) was 74% in infected EP and 21.8% in uninfected EP and 11.8% tubal ligation controls (P < 0.0001), while the frequency of AG or GG genotype of CD63 A/G polymorphism (rs376086542) was 48.1% in infected EP and 41.3% in uninfected EP and 18.6% tubal ligation controls (P < 0.0001). CONCLUSIONS: The present study revealed a strong association between the presence of gene variants MMP2 (rs17859882 G/T, rs7201A/C) and CD63 (rs2231464 C/T, rs376086542 A/G) and risk of tubal EP during C. trachomatis infection.

Seroprevalence of Chlamydia trachomatis and associated risk factors among HIV positive women in North Central Nigeria.

Introduction: Chlamydia trachomatis infection is among the STDs that are known to increase the risk of HIV infection. The present study aims to determine the seroprevalence of C. trachomatis among HIV positive women in Ilorin and Offa, Kwara State, North Central Nigeria. Methods: Serum samples from 400 HIV positive women attending the HAART Clinic in Offa and the Ilorin General Hospital in Kwara State, Nigeria, were screened using Enzyme Linked Immunosorbent Assay (ELISA), utilizing the immunocomb Chlamydia IgG test kit (Calbiotech, El Cajon, CA, USA) to check for the existence of anti-C. trachomatis antibodies. Result: Anti-C. trachomatis antibodies were present in 92 (23.0%) of the 400 HIV positive women samples. There was a higher prevalence among the age group 36-40 years. Hence, age groupings were statistically and significantly associated (p=0.001) with the seroprevalence of C. trachomatis among HIV positive women. Married HIV positive women (60.9%) had the highest prevalence of C. trachomatis, with a statistically significant association (p=0.001). There was a statistically significant association between the number of sexual partner(s) (p=0.001) and the seroprevalence of C. trachomatis among HIV positive women. Conclusions: The high frequency confirms the necessity for comprehensive sexual education among young adults and routine testing for anti-C. trachomatis. It reflects the endemicity of the infection in Ilorin and Offa Kwara State, Nigeria.

Antibodies from chlamydia-infected individuals facilitate phagocytosis via Fc receptors.

Non-neutralizing functions of antibodies, including phagocytosis, may play a role in Chlamydia trachomatis (CT) infection, but these functions have not been studied and assays are lacking. We utilized a flow-cytometry-based assay to determine whether serum samples from a well-characterized cohort of CT-infected and naïve control individuals enhanced phagocytosis via Fc-receptor-expressing THP-1 cells, and whether this activity correlated with antibody titers. Fc-receptor-mediated phagocytosis was detected only in CT+ donors. Phagocytosis generally did not correlate well with antibody titer. In addition, we found that complement from both CT+ and negative individuals enhanced phagocytosis of CT into primary neutrophils. These results suggest that anti-CT antibodies can have functions that are not reflected by titer. This method could be used to quantitively measure Fc-receptor-mediated function of anti-CT antibodies or complement activity and could reveal new immune correlates of protection.

Genomic insights into local-scale evolution of ocular Chlamydia trachomatis strains within and between individuals in Gambian trachoma-endemic villages.

Trachoma, a neglected tropical disease caused by Chlamydia trachomatis (Ct) serovars A-C, is the leading infectious cause of blindness worldwide. Africa bears the highest burden, accounting for over 86 % of global trachoma cases. We investigated Ct serovar A (SvA) and B (SvB) whole genome sequences prior to the induction of mass antibiotic drug administration in The Gambia. Here, we explore the factors contributing to Ct strain diversification and the implications for Ct evolution within the context of ocular infection. A cohort study in 2002-2003 collected ocular swabs across nine Gambian villages during a 6 month follow-up study. To explore the genetic diversity of Ct within and between individuals, we conducted whole-genome sequencing (WGS) on a limited number (n=43) of Ct-positive samples with an omcB load ≥10 from four villages. WGS was performed using target enrichment with SureSelect and Illumina paired-end sequencing. Out of 43 WGS samples, 41 provided sufficient quality for further analysis. ompA analysis revealed that 11 samples had highest identity to ompA from strain A/HAR13 (NC_007429) and 30 had highest identity to ompA from strain B/Jali20 (NC_012686). While SvB genome sequences formed two distinct village-driven subclades, the heterogeneity of SvA sequences led to the formation of many individual branches within the Gambian SvA subclade. Comparing the Gambian SvA and SvB sequences with their reference strains, Ct A/HAR13 and Ct B/Jali20, indicated an single nucleotide polymorphism accumulation rate of 2.4×10-5 per site per year for the Gambian SvA and 1.3×10-5 per site per year for SvB variants (P<0.0001). Variant calling resulted in a total of 1371 single nucleotide variants (SNVs) with a frequency >25 % in SvA sequences, and 438 SNVs in SvB sequences. Of note, in SvA variants, highest evolutionary pressure was recorded on genes responsible for host cell modulation and intracellular survival mechanisms, whereas in SvB variants this pressure was mainly on genes essential for DNA replication/repair mechanisms and protein synthesis. A comparison of the sequences between observed separate infection events (4-20 weeks between infections) suggested that the majority of the variations accumulated in genes responsible for host-pathogen interaction such as CTA_0166 (phospholipase D-like protein), CTA_0498 (TarP) and CTA_0948 (deubiquitinase). This comparison of Ct SvA and SvB variants within a trachoma endemic population focused on their local evolutionary adaptation. We found a different variation accumulation pattern in the Gambian SvA chromosomal genes compared with SvB, hinting at the potential of Ct serovar-specific variation in diversification and evolutionary fitness. These findings may have implications for optimizing trachoma control and prevention strategies.

Intranasal delivery of Salmonella OMVs decorated with Chlamydia trachomatis antigens induces specific local and systemic immune responses.

Chlamydia trachomatis is an obligate intracellular pathogen responsible for the most prevalent bacterial sexually transmitted disease globally. The high prevalence of chlamydial infections underscores the urgent need for licensed and effective vaccines to prevent transmission in populations. Bacterial outer membrane vesicles (OMVs) have emerged as promising mucosal vaccine carriers due to their inherent adjuvant properties and the ability to display heterologous antigens. In this proof-of-concept study, we evaluated the immunogenicity of Salmonella OMVs decorated with C. trachomatis MOMP-derived CTH522 or HtrA antigens in mice. Following a prime-boost intranasal vaccination approach, two OMV-based C. trachomatis vaccines elicited significant humoral responses specific to the antigens in both systemic and vaginal compartments. Furthermore, we demonstrated strong antigen-specific IFN-γ and IL17a responses in splenocytes and cervical lymph node cells of vaccinated mice, indicating CD4+ Th1 and Th17 biased immune responses. Notably, the OMV-CTH522 vaccine also induced the production of spleen-derived CD8+ T cells expressing IFN-γ. In conclusion, these results highlight the potential of OMV-based C. trachomatis vaccines for successful use in future challenge studies and demonstrate the suitability of our modular OMV platform for intranasal vaccine applications.

Genotypic study of Chlamydia trachomatis for lymphogranuloma venereum diagnosis in rectal specimens from men who have sex with men: a cost-effectiveness analysis.

PURPOSE: The significant proportion of asymptomatic patients and the scarcity of genotypic analysis of lymphogranuloma venereum (LGV), mainly among men who have sex with men (MSM), triggers a high incidence of underdiagnosed patients, highlighting the importance of determining the most appropriate strategy for LGV diagnosis, at both clinical and economical levels. MATERIALS AND METHODS: We conducted L1-L3 serovar detection by molecular biology in stored Chlamydia trachomatis-positive samples from MSM patients with HIV, another STI or belonging to a Pre-exposure prophylaxis program, to make a cost effectiveness study of four diagnostic strategies with a clinical, molecular, or mixed approach. RESULTS: A total of 85 exudates were analyzed: 35urethral (31 symptomatic/4 positive) and 50 rectal (22 symptomatic/25 positive), 70/85 belonging to MSM with associated risk factors. The average cost per patient was €77.09 and €159.55 for clinical (Strategy I) and molecular (Strategy IV) strategies respectively. For molecular diagnosis by genotyping of all rectal exudate samples previously positive for CT (Strategy II), the cost was €123.84. For molecular diagnosis by genotyping of rectal and/or urethral exudate samples from all symptomatic patients (proctitis or urethritis) with a previous positive result for CT (Strategy III), the cost was €129.39. The effectiveness ratios were 0.80, 0.95, 0.91, and 1.00 for each strategy respectively. The smallest ICER was €311.67 for Strategy II compared to Strategy I. CONCLUSIONS: With 30% asymptomatic patients, the most cost-effective strategy was based on genotyping all rectal exudates. With less restrictive selection criteria, thus increasing the number of patients with negative results, the most sensitive strategies tend to be the most cost-effective, but with a high incremental cost-effectiveness ratio.

Prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Mycoplasma genitalium and risk factors among pregnant women in Brazil: Results from the national molecular diagnosis implementation project.

BACKGROUND: Sexually transmitted infections (STIs) are a public health problem. The aim of the present study was to assess the prevalence and risk factors associated with at least one STI (Chlamydia trachomatis [CT], Neisseria gonorrhoeae [NG], Trichomonas vaginalis [TV], and Mycoplasma genitalium [MG]) in Brazil. METHODS: A cross-sectional study was conducted using secondary data from the pilot implementation of the National Service for molecular diagnosis of CT, NG, TV, and MG in pregnancy. We obtained Ministry of Health surveillance data from the implementation project. Data encompassing pregnant women aged 15-49 years from public antenatal clinics in Brazil in 2022 were included. RESULTS: A total of 2728 data of pregnant women were analyzed. The prevalence of at least one infection was 21.0% (573), with the highest prevalence in the Southeast region (23.3%) and the lowest in the Center-West region (15.4%). The prevalence of CT was 9.9% (270), NG 0.6% (16), TV 6.7% (184), and MG 7.8% (212). Factors associated with any infection were from 15 to 24 years (AOR = 1.93; 95% CI: 1.58-2.35); reported family income up to US$400 (AOR = 1.79; 95% CI: 1.03-3.34); declared not living maritally with their partners (AOR = 1.90, 95% CI: 1.52-2.37) and had more than one sexual partner in their lifetime (AOR = 2.09, 95% CI: 1.55-2.86). CONCLUSION: This study showed a high prevalence of at least one STI among pregnant women in Brazil, particularly among younger women. It also provides up-to-date national data on CT, NG, TV, and MG infections in this population. These findings underscore the importance of enhancing access to STI screening for young pregnant women within the Brazilian public health system.

ompA Sequencing and Multilocus Sequence Typing of Lymphogranuloma Venereum Cases in Buenos Aires Reveal New Chlamydia trachomatis Genotypes.

Since the Lymphogranuloma venereum (LGV) outbreak was first described in Buenos Aires in 2017, the detected strains presented peculiar characteristics. Our goal was to increase the understanding of the strains involved in the LGV outbreak in Argentina. We characterized the ompA gene sequences, using Sanger sequencing, of 88 LGV strains from 239 symptomatic patients in Buenos Aires enrolled between 2017 and 2019, and selected 20 C. trachomatis strains for further characterization using Multilocus Sequence Typing (MLST). Following the ompA gene analysis of the 88 LGV strains, we detected 43% L2b, 31% L1-like, and 26% L2. Among the 38 L2b samples analyzed, there were 7 distinct sequences, 3 of them not previously reported (L2bv12, L2bv13, and L2bv14). Additionally, we detected a strain with a new mutation (AM884176.1:g.59122A>T) found in the position defining L2 or L2b, proposed as L2i. Using MLST, five different sequence types (STs) were detected, including the ST2 (corresponding to the L1-like strains) and a new one (ST60). ST58 was associated with the concomitant presence of another STI and HIV. A high genetic diversity in C. trachomatis LGV strains in Argentina was observed in a short period of time, with a relatively low number of samples from a limited geographical area.

The serodiagnositic value of Chlamydia trachomatis antigens in antibody detection using luciferase immunosorbent assay.

Introduction: Among the different antigens used in the detection of anti-Chlamydia trachomatis antibodies, significant differences in sensitivity and specificity have been observed. Further evaluation of C. trachomatis antigens in antibody detection is urgently needed for the development and application of C. trachomatis serologic assays. Methods: Chlamydia trachomatis antigens Pgp3, TmeA, InaC, and HSP60 were selected and used in luciferase immunosorbent assay (LISA). The detection results obtained from well-defined C. trachomatis positive and negative samples were compared with the commercial C. trachomatis ELISA (Mikrogen) for performance evaluation. Results: Pgp3, TmeA, InaC, and HSP60-based LISA showed sensitivity of 92.8, 88.8, 90.4, and 94.4%, and specificity of 99.2, 99.2, 99.2, and 92%, respectively. ROC analysis indicated that Pgp3-based LISA showed similar performance to Mikrogen ELISA (AUC 0.986 vs. 0.993, p = 0.207). Furthermore, four C. trachomatis antigens achieved strong diagnostic efficiency, i.e., positive likelihood ratios [+LR] ≥ 10 in C. trachomatis-infected women and negative likelihood ratios [-LR] ≤ 0.1 in C. trachomatis negative low exposure risk children, but only Pgp3 and TmeA showed strong diagnostic value in general adults. In addition, Pgp3, TmeA, and InaC, but not HSP60, achieved high performance, i.e., both positive predictive value (PPV) and negative predictive value (NPV) ≥ 90.9%, and showed no significant cross-reactivity with anti-Chlamydiapneumoniae. Conclusion: Three C. trachomatis species-specific antigens Pgp3, TmeA, and InaC show superior performance in the detection of anti-C. trachomatis antibody, indicating the potential to be used in developing C. trachomatis serologic tests.

Chronic sexually acquired reactive arthritis secondary to Chlamydiatrachomatis.

Reactive arthritis is included in the spectrum of seronegative spondyloarthritides, occurring secondary to triggers of genitourinary and gastrointestinal tract infections. We describe two cases of sexually acquired reactive arthritis secondary to genital infection by Chlamydia trachomatis, diagnosed by in-house polymerase chain reaction performed on the first void urine. Both patients were managed with a combined approach of short course antibiotics, immunosuppressive agents, biologicals and surgical intervention.

Insights into innate immune cell evasion by Chlamydia trachomatis.

Chlamydia trachomatis, is a kind of obligate intracellular pathogen. The removal of C. trachomatis relies primarily on specific cellular immunity. It is currently considered that CD4+ Th1 cytokine responses are the major protective immunity against C. trachomatis infection and reinfection rather than CD8+ T cells. The non-specific immunity (innate immunity) also plays an important role in the infection process. To survive inside the cells, the first process that C. trachomatis faces is the innate immune response. As the "sentry" of the body, mast cells attempt to engulf and remove C. trachomatis. Dendritic cells present antigen of C. trachomatis to the "commanders" (T cells) through MHC-I and MHC-II. IFN-γ produced by activated T cells and natural killer cells (NK) further activates macrophages. They form the body's "combat troops" and produce immunity against C. trachomatis in the tissues and blood. In addition, the role of eosinophils, basophils, innate lymphoid cells (ILCs), natural killer T (NKT) cells, γδT cells and B-1 cells should not be underestimated in the infection of C. trachomatis. The protective role of innate immunity is insufficient, and sexually transmitted diseases (STDs) caused by C. trachomatis infections tend to be insidious and recalcitrant. As a consequence, C. trachomatis has developed a unique evasion mechanism that triggers inflammatory immunopathology and acts as a bridge to protective to pathological adaptive immunity. This review focuses on the recent advances in how C. trachomatis evades various innate immune cells, which contributes to vaccine development and our understanding of the pathophysiologic consequences of C. trachomatis infection.