Chlamydia and Gonorrhea Co-occurrence in a High School Population

Neisseria gonorrhoeae Coinfection during Chlamydia muridarum Genital Latency Does Not Modulate Murine Vaginal Bacterial Shedding

Chlamydia trachomatis and Neisseria gonorrhoeae are the most frequently reported agents of bacterial sexually transmitted disease worldwide. Nonetheless, C. trachomatis/N. gonorrhoeae coinfection remains understudied. C. trachomatis/N. gonorrhoeae coinfections are more common than expected by chance, suggesting C. trachomatis/N. gonorrhoeae interaction, and N. gonorrhoeae infection may reactivate genital chlamydial shedding in women with latent (quiescent) chlamydial infection. We hypothesized that N. gonorrhoeae would reactivate latent genital Chlamydia muridarum infection in mice. Two groups of C. muridarum-infected mice were allowed to transition into genital latency. One group was then vaginally inoculated with N. gonorrhoeae; a third group received N. gonorrhoeae alone. C. muridarum and N. gonorrhoeae vaginal shedding was measured over time in the coinfected and singly infected groups. Viable C. muridarum was absent from vaginal swabs but detected in rectal swabs, confirming C. muridarum genital latency and consistent with the intestinal tract as a C. muridarum reservoir. C. muridarum inclusions were observed in large intestinal, but not genital, tissues during latency. Oviduct dilation was associated with C. muridarum infection, as expected. Contradicting our hypothesis, N. gonorrhoeae coinfection did not reactivate latent C. muridarum vaginal shedding. In addition, latent C. muridarum infection did not modulate recovery of vaginal viable N. gonorrhoeae. Evidence for N. gonorrhoeae-dependent increased C. muridarum infectivity has thus not been demonstrated in murine coinfection, and the ability of C. muridarum coinfection to potentiate N. gonorrhoeae infectivity may depend on actively replicating vaginal C. muridarum. The proportion of mice with increased vaginal neutrophils (PMNs) was higher in N. gonorrhoeae-infected than in C. muridarum-infected mice, as expected, while that of C. muridarum/N. gonorrhoeae-coinfected mice was intermediate to the singly infected groups, suggesting latent C. muridarum murine infection may limit PMN response to subsequent N. gonorrhoeae infection. IMPORTANCE Our work builds upon the limited understanding of C. muridarum/N. gonorrhoeae coinfection. Previously, N. gonorrhoeae infection of mice with acute (actively replicating) vaginal C. muridarum infection was shown to increase recovery of viable vaginal N. gonorrhoeae and vaginal PMNs, with no effect on C. muridarum vaginal shedding (R. A. Vonck et al., Infect Immun 79:1566-1577, 2011). It has also been shown that chlamydial infection of human and murine PMNs prevents normal PMN responses, including the response to N. gonorrhoeae (K. Rajeeve et al., Nat Microbiol 3:824-835, 2018). Our findings show no effect of latent genital C. muridarum infection on the recovery of viable N. gonorrhoeae, in contrast to the previously reported effect of acute C. muridarum infection, and suggesting that acute versus latent C. muridarum infection may have distinct effects on PMN function in mice. Together, these studies to date provide evidence that Chlamydia/N. gonorrhoeae synergistic interactions may depend on the presence of replicating Chlamydia in the genital tract, while chlamydial effects on vaginal PMNs may extend beyond acute infection.

Meningococcal Urethritis: Old and New

Neisseria meningitidis is a common commensal bacterium found in the respiratory tract, but it can also cause severe, invasive disease. Vaccines have been employed which have been successful in helping to prevent invasive disease caused by encapsulated N. meningitidis from the A, C, W, Y, and B serogroups. Currently, nonencapsulated N. meningitidis groups are more common commensals in the population than in the prevaccine era. One emerging nonencapsulated group of bacteria is the U.S. N. meningitidis urethritis clade (US_NmUC), which can cause meningococcal urethritis in men. US_NmUC has unique genotypic and phenotypic features that may increase its fitness in the male urethra. It is diagnostically challenging to identify and distinguish meningococcal urethritis from Neisseria gonorrhoeae, as the clinical presentation and microbiological findings are overlapping. In this review, the history of meningococcal urethritis, emergence of US_NmUC, laboratory diagnosis, and clinical treatment are all explored.

Who Is Best to Test? A Systematic Review of Chlamydia Infections in Switzerland

In many countries, community pharmacies provide sexual-health-related services to limit the spread of sexually transmitted infections (STIs), including chlamydia testing. To identify suitable target groups for pharmacy-based chlamydia testing in Switzerland, we aimed to assess chlamydia prevalence, identify risk groups, and delineate screening strategies. We conducted a systematic literature search up to December 2019 in PubMed, EMBASE, and Web of Science, according to the PRISMA guidelines, using as keywords “chlamydia”, “screening”, and “Switzerland”. Two researchers screened the title, abstract, and full-text article and assessed the methodological quality. The literature search generated 108 hits, and nine studies were included. Chlamydia prevalence ranged between 0.8 and 12.8%. Most frequently affected were undocumented women undergoing voluntary termination of pregnancy (12.8%, 95% CI: 8.4–18.9), HIV-positive men who have sex with men (10.9%, 95% CI: 9.2–17.6), and adult offenders (6.5%, 95% CI: 3.2–9.0). Systematic screening was suggested for the first two risk groups and women suffering a miscarriage. To conclude, chlamydia infections are prevalent in Switzerland, but the identified risk groups are difficult to reach for a pharmacy-based testing service. More studies are needed to identify suitable target groups, including customers seeking sexual health services, particularly emergency contraception users who already receive counselling for STIs at community pharmacies.

C hlamydia trachomatis during pregnancy and childhood asthma-related morbidity: a population-based prospective cohort

INTRODUCTION

Chlamydia trachomatis is the most commonly reported sexually transmitted disease and although infection during pregnancy is associated with neonatal complications, long-term respiratory consequences are unknown. We aimed to determine whether C. trachomatis infection during pregnancy is associated with asthma-related symptoms across childhood METHODS: This study among 2475 children and their mothers was embedded in a population-based prospective cohort study. Maternal urine samples were tested for C. trachomatis infection during pregnancy. Questionnaires provided information on childhood physician-attended lower respiratory tract infections and wheezing, and current asthma at age 10 years. Lung function was measured by spirometry at age 10 years.

RESULTS

The prevalence of C. trachomatis infection during pregnancy was 3.2% (78 out of 2475). C. trachomatis infection during pregnancy was not associated with lower respiratory tract infections until age 6 years, but was associated with a higher odds of wheezing in children until age 10 years (OR 1.50 (95% CI 1.10-2.03)). C. trachomatis infection during pregnancy was associated with an increased odds of asthma (OR 2.29 (95% CI 1.02-5.13)), and with a lower forced expiratory volume in 1 s/forced vital capacity and forced expiratory flow at 75% of forced vital capacity (z-score difference -0.28 (95% CI -0.52- -0.04) and -0.24 (95% CI -0.46- -0.01), respectively) in children at age 10 years. The observed associations were only partly explained by mode of delivery, gestational age at birth or birthweight.

CONCLUSIONS

C. trachomatis infection during pregnancy is associated with increased odds of wheezing, asthma and impaired lung function. The causality of the observed associations and potential underlying mechanisms need to be explored.

Characterization and Trend of Co-Infection with Neisseria gonorrhoeae and Chlamydia trachomatis from the Korean National Infectious Diseases Surveillance Database

Purpose

We analyzed the database from the Korean National Infectious Diseases Surveillance to reveal clinical characteristics of co-infection with Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT).

Materials and Methods

Eligible cases included a single NG infection (male/female) for 6,421 (4,975/1,446), a single CT infection for 20,436 (6,107/14,329), and co-infection for 498 (233/265) between 2011 and 2015.

Results

Cases of NG and CT have increased for 5 years; the proportion of co-infected male has increased continuously and was positively correlated with that of CT infections. But the proportion of co-infected female was positively correlated with that of NG infections, following an expanded wavelike-pattern. Generally, people with co-infection was younger than either infection alone (p=0.001). But the characteristics of co-infection revealed sex-specific differences. While the co-infected females were younger than females in NG (p=0.001) or CT group (p=0.001), the co-infected males were younger than males in CT (p=0.001) only, not males in the NG group (p=0.394). Amongst males, 4.47% with NG had CT infection, while in female 15.49% with NG had CT (p=0.001). In contrast, in male 3.68% with CT infection had NG infection and in female 1.82% of CT had NG (p=0.001). Young people in both sexes have increased risks of co-infection bi-directionally (all p=0.001), except males with NG that were also co-infected with CT (p=0.642).

Conclusions

The sex-specific findings in co-infection may improve understanding of gender-specific characteristics in NG and CT infections. Co-infected people are increasing for 5 years. Therefore, we must consider long-term complication of the co-infected people.

Biological feasibility and importance of a gonorrhea vaccine for global public health

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78 million new infections annually; greatest impact on women and neonates in LMIC.

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Current control measures are inadequate and challenged by antibiotic resistance.

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Conserved candidate vaccine antigens and adjuvant strategies are being developed.

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There is a need for human studies to investigate correlates of immunity.

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A meningococcal outer membrane vesicle vaccine may protect against gonorrhea.

There is a growing public health interest in controlling sexually transmitted infections (STIs) through vaccination due to increasing recognition of the global disease burden of STIs and the role of STIs in women’s reproductive health, adverse pregnancy outcomes, and the health and well-being of neonates. Neisseria gonorrhoeae has historically challenged vaccine development through the expression of phase and antigenically variable surface molecules and its capacity to cause repeated infections without inducing protective immunity. An estimated 78 million new N. gonorrhoeae infections occur annually and the greatest disease burden is carried by low- and middle-income countries (LMIC). Current control measures are clearly inadequate and threatened by the rapid emergence of antibiotic resistance. The gonococcus now holds the status of “super-bug” as there is currently no single reliable monotherapy for empirical treatment of gonorrhea. The problem of antibiotic resistance has elevated treatment costs and necessitated the establishment of large surveillance programs to track the spread of resistant strains. Here we review the need for a gonorrhea vaccine with respect to global disease burden and related socioeconomic and treatment costs, with an emphasis on the impact of gonorrhea on women and newborns. We also highlight the challenge of estimating the impact of a gonorrhea vaccine due to the need for more data on the burden of gonococcal pelvic inflammatory disease and related sequelae and of gonorrhea-associated adverse pregnancy outcomes and the problem of empirical diagnosis and treatment of STIs in LMIC. There is also a lack of clinical and basic science research in the area of gonococcal/chlamydia coinfection, which occurs in a high percentage of individuals with gonorrhea and should be considered when testing the efficacy of gonorrhea vaccines. Finally, we review recent research that suggests a gonorrhea vaccine is feasible and discuss challenges and research gaps in gonorrhea vaccine development.

School-Based Sexually Transmitted Disease Screening: Review and Programmatic Guidance

School-based sexually transmitted disease (STD) screening (SBSS) was designed to provide chlamydia and gonorrhea testing, treatment, and counseling to adolescents in a school setting to overcome some of the difficulties of screening in this population. To inform STD control programs and other entities on decision making about potentially implementing this intervention, we reviewed existing published and gray literature on SBSS from 1998 to 2014. Although they are work-intensive to establish, school-based STD screening programs are a feasible and cost-effective way of testing large numbers of male and female adolescents for chlamydia and gonorrhea, and to provide counseling and treatment to almost all those who are found infected. School-based STD screening programs do not seem to reduce prevalence in either the school or the general adolescent population, although there are currently relatively few studies on large-scale SBSS. More research in this field is needed.

Structural characterization of muropeptides from Chlamydia trachomatis peptidoglycan by mass spectrometry resolves "chlamydial anomaly"

The "chlamydial anomaly," first coined by James Moulder, describes the inability of researchers to detect or purify peptidoglycan (PG) from pathogenic Chlamydiae despite genetic and biochemical evidence and antibiotic susceptibility data that suggest its existence. We recently detected PG in Chlamydia trachomatis by a new metabolic cell wall labeling method, however efforts to purify PG from pathogenic Chlamydiae have remained unsuccessful. Pathogenic chlamydial species are known to activate nucleotide-binding oligomerization domain-containing protein 2 (NOD2) innate immune receptors by as yet uncharacterized ligands, which are presumed to be PG fragments (muramyl di- and tripeptides). We used the NOD2-dependent activation of NF-κB by C. trachomatis-infected cell lysates as a biomarker for the presence of PG fragments within specific lysate fractions. We designed a new method of muropeptide isolation consisting of a double filtration step coupled with reverse-phase HPLC fractionation of Chlamydia-infected HeLa cell lysates. Fractions that displayed NOD2 activity were analyzed by electrospray ionization mass spectrometry, confirming the presence of muramyl di- and tripeptides in Chlamydia-infected cell lysate fractions. Moreover, the mass spectrometry data of large muropeptide fragments provided evidence that transpeptidation and transglycosylation reactions occur in pathogenic Chlamydiae. These results reveal the composition of chlamydial PG and disprove the "glycanless peptidoglycan" hypothesis.

Coinfection with Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis: a cross-sectional analysis of positivity and risk factors in remote Australian Aboriginal communities

OBJECTIVES

To determine the co-occurrence and epidemiological relationships of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) in a high-prevalence setting in Australia.

METHODS

In the context of a cluster randomised trial in 68 remote Aboriginal communities, we obtained laboratory reports on simultaneous testing for CT, NG and TV by nucleic acid amplification tests in individuals aged ≥16 years and examined relationships between age and sex and the coinfection positivity. ORs were used to determine which infections were more likely to co-occur by demographic category.

RESULTS

Of 13 480 patients (median age: 30 years; men: 37%) tested for all three infections during the study period, 33.3% of women and 21.3% of men had at least one of them, highest in patients aged 16-19 years (48.9% in women, 33.4% in men). The most frequent combination was CT/NG (2.0% of women, 4.1% of men), and 1.8% of women and 0.5% of men had all three. In all co-combinations, coinfection positivity was highest in patients aged 16-19 years. CT and NG were highly predictive of each other's presence, and TV was associated with each of the other two infections, but much more so with NG than CT, and its associations were much stronger in women than in men.

CONCLUSIONS

In this remote high-prevalence area, nearly half the patients aged 16-19 years had one or more sexually transmitted infections. CT and NG were more common dual infections. TV was more strongly associated with NG coinfections than with CT. These findings confirm the need for increased simultaneous screening for CT, NG and TV, and enhanced control strategies.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ACTRN12610000358044.

Chlamydia positivity in New Orleans public high schools, 1996-2005: implications for clinical and public health practices

OBJECTIVE

To describe the trends in chlamydia positivity among New Orleans high school students tested in a schoolwide screening between 1996 and 2005, and to determine factors associated with chlamydia positivity among students during the 10-year period.

METHODS

Between school years 1995-1996 and 2004-2005, students in New Orleans public high schools were tested for chlamydia using nucleic acid amplification tests (NAAT) in urine specimens (LCx assay until 1999-2000; BD assay from 2000-2001 to 2004-2005). For each year, we calculated chlamydia positivity by dividing the number of students testing positive by the total number of students tested. Data were analyzed separately by gender. Logistic regressions were performed to determine independent predictors of chlamydia positivity during the 10-year period.

RESULTS

Between 1996 and 2005, the average chlamydia positivity was 7.0% (95% confidence interval 6.6-7.4) in boys and 13.1% (95% confidence interval 12.6-13.7) in girls (P < .001). Chlamydia detection increased with the switch from LCx to BD assay. In multivariate analyses, chlamydia positivity among boys and girls was significantly associated with age, black race, and gonorrhea coinfection. Additionally, positivity was significantly different by school year among boys (P = .03) and by NAAT used among girls (P = .008).

CONCLUSIONS

The trends in chlamydia positivity observed between 1996 and 2005 more likely reflected a high and stable prevalence of chlamydia in the New Orleans school-age adolescent population. Any benefit of screening on individuals tested was likely to be mitigated by participants' uninterrupted social interactions with the dynamic forces that sustain the sexual transmission of chlamydia in the population.

Human immunodeficiency virus and chlamydia/gonorrhea testing among heterosexual college students: who is getting tested and why do some not?

OBJECTIVE

This study explored college students' reported history of human immunodeficiency virus (HIV) and chlamydia/gonorrhea and characteristics of students reporting testing. Additionally, it assessed their motivation regarding future testing and reasons for lack of motivation.

PARTICIPANTS

The sample consisted of 292 sexually experienced college students self-identifying as heterosexual at a midwestern university.

METHODS

Participants completed a 26-item survey during the 2010-2011 academic year.

RESULTS

Demographics (sex, age, race/ethnicity), behaviors (higher numbers of sex partners, currently not using condoms), and motivation for future testing distinguished those who had been tested ever and those who had not. Half of participants were not motivated to seek testing in the next 3 months; the most common reason for no motivation being perceived lack of risk.

CONCLUSIONS

Interventions promoting testing can use these findings to target those likely to never have been tested. These results also highlight the need to find ways to motivate students to get tested.

Point-of-care tests for the diagnosis of Neisseria gonorrhoeae infection: a systematic review of operational and performance characteristics

OBJECTIVES

Systematic review of the performance and operational characteristics of point-of-care (POC) tests for the diagnosis of Neisseria gonorrhoeae.

METHODS

We searched PubMed and Embase until August 2010 using variations of the terms: 'rapid test', 'Neisseria gonorrhoeae' and 'evaluation'.

RESULTS

We identified 100 papers, 14 studies were included; nine evaluated leucocyte esterase (LE) dipsticks and three immunochromatographic strips, and two clinical audits of microscopy were identified. Of the field evaluations the gold standard was nucleic acid amplification technology in six studies and bacterial culture in the other six. In four studies, 50% or more of the patients were symptomatic. The median sensitivity of LE dipsticks was 71% (range 23-85%), median specificity was 70% (33-99%), median positive predictive value (PPV) was 19% (5-40%) and median negative predictive value (NPV) was 95% (56-99%). One LE study found a sensitivity of 23% overall, increasing to 75% in symptomatic women. LE dipsticks mostly involved three steps and took under 2 min. The median sensitivity of immunochromatographic tests (ICT) was 70% (60-94%), median specificity was 96% (89-97%), median PPV was 56% (55-97%) and median NPV was 93% (92-99%). Immunochromatic strips involved five to seven steps and took 15-30 min. Specificity of microscopy ranged from 38% to 89%.

CONCLUSIONS

ICT and LE tests had similar sensitivities, but sensitivity results may be overestimated as largely symptomatic patients were included in some studies. ICT had a higher specificity in women than LE tests. The findings highlight the need for improved POC tests for diagnosis of N gonorrhoeae and more standardised evaluations.

Patterns of chlamydia/gonorrhea positivity among voluntarily screened New York City public high school students

PURPOSE

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) are common sexually transmitted infections that disproportionately affect adolescents. Annual screening for CT for sexually active female adolescents is recommended. In 2006, New York City began conducting CT/GC education, screening, and treatment in public high schools. We examine 3-year programmatic outcomes and the relationship between sexual activity, screening, and CT/GC positivity.

METHODS

We describe the epidemiology of students who screened and those infected with CT/GC. Univariate, bivariate, and multivariate logistic regression analyses were performed to assess relationships between sex, race/ethnicity, age, sexual activity, and screening status; and the relationship between sexually transmitted infection positivity and sexual activity.

RESULTS

Between July 2006 and June 2009, we educated 57,418 students and screened 27,353 (47.6%) for CT/GC; 1,736 (6.3%) students were reported to be infected with either organism. Students who screened positive were more likely to be females (8.9%), report black race (8.3%) and be ≥16 years of age (6.6%-9.7%). Screening rates were 70.6% for students who were sexually active, 27.9% for those who had never had sex, and 47.3% for those who did not respond to the sexual activity question; CT/GC positivity was 7.2%, 1.4%, and 6.1%, respectively.

CONCLUSIONS

Black, older adolescent females were most likely to screen positive for CT/GC in this population. A large proportion of students who did not answer the sexual activity question chose to screen for CT/GC and screened positive. School screening programs should offer screening to all students regardless of reported sexual activity. Programs should target females and older adolescents.

Risk of coinfection with Chlamydia trachomatis and Neisseria gonorrhoeae in Nova Scotia

BACKGROUND

The frequency of Chlamydia trachomatis and Neisseria gonorrhoeae coinfection can vary depending on their individual incidence and prevalence rates.

OBJECTIVE

To determine the frequency of C trachomatis and N gonorrhoeae coinfections by evaluating the results of testing in 2007 and 2008 to better inform testing and treatment decisions.

METHODS

Specimens from the same patient submitted on the same day served as the basis for the present study. The age, sex and the source of the specimen were also linked to the accession number. Infection and coinfection rates were analyzed in both males and females.

RESULTS

Concurrent testing was performed on 41,567 female specimens and 1827 male specimens, of which, 1495 female samples (3.6%) tested positive for C trachomatis infection and 88 (0.2%) tested positive for N gonorrhoeae infections. Only 31 females were coinfected; however, for those between 11 and 25 years of age, 25 of 61 females (40.1%) with N gonorrhoeae infection also tested positive for C trachomatis infection; conversely, 25 of 1248 females (2.0%) with C trachomatis infection also tested positive for N gonorrhoeae infection. For males, 213 (11.7%) tested positive for C trachomatis infection, and 59 (3.2%) tested positive for N gonorrhoeae infection. In 30 males with N gonorrhoeae between 11 and 25 years of age, and 149 males with C trachomatis, eight coinfections were observed (26.7% and 5.3%, respectively). Of those older than 25 years of age, only five of 905 men and six of 19,465 women were coinfected. None of the 10,935 women who were 30 years of age or older had coinfections.

CONCLUSION

The N gonorrhoeae coinfection rate in males with C trachomatis may justify empirical antimicrobials; however, in females, the proportion of coinfected may not justify empirical treatment for N gonorrhoeae infection when the C trachomatis test is positive and N gonorrhoeae testing has not been performed.

Estradiol-Treated Female Mice as Surrogate Hosts for Neisseria gonorrhoeae Genital Tract Infections

Historically, animal modeling of gonorrhea has been hampered by the exclusive adaptation of Neisseria gonorrhoeae to humans. Genital tract infection can be established in female mice that are treated with 17β-estradiol, however, and many features of experimental murine infection mimic human infection. Here we review the colonization kinetics and host response to experimental murine gonococcal infection, including mouse strain differences and evidence that IL-17 responses, toll-like receptor 4, and T regulatory cells play a role in infection. We also discuss the strengths and limitations of the mouse system and the potential of transgenic mice to circumvent host restrictions. Additionally, we review studies with genetically defined mutants that demonstrated a role for sialyltransferase and the MtrC-MtrD-MtrE active efflux pump in evading innate defenses in vivo, but not for factors hypothesized to protect against the phagocytic respiratory burst and H(2)O(2)-producing lactobacilli. Studies using estradiol-treated mice have also revealed the existence of non-host-restricted iron sources in the female genital tract and the influence of hormonal factors on colonization kinetics and selection for opacity (Opa) protein expression. Recent work by others with estradiol-treated mice that are transgenic for human carcinoembryonic adhesion molecules (CEACAMs) supports a role for Opa proteins in enhancing cellular attachment and thus reduced shedding of N. gonorrhoeae. Finally we discuss the use of the mouse model in product testing and a recently developed gonorrhea chlamydia coinfection model.

Aptima Combo 2 testing detected additional cases of Neisseria gonorrhoeae infection in men and women in community settings

Aptima Combo 2 (AC2) Neisseria gonorrhoeae testing of 81,405 patients who were tested by culture and 14,666 who were AC2 tested for Chlamydia trachomatis detected 142 extra infections and confirmed 106 culture-positive samples (the positivity rate increased from 0.13 in testing by culture to 0.26 in testing by AC2). Retrievable AC2 positive samples were confirmed (98.5%) by an alternate AGC test.

Chlamydial infection increases gonococcal colonization in a novel murine coinfection model

Genital tract infections caused by Neisseria gonorrhoeae and Chlamydia trachomatis serovars D to K occur at high incidence in many areas of the world. Despite high rates of coinfection with these pathogens, investigations of host-parasite interactions have focused on each pathogen individually. We describe here a coinfection model in which female BALB/c mice were first infected with the mouse Chlamydia species C. muridarum and then inoculated with N. gonorrhoeae following treatment with water-soluble 17β-estradiol to promote long-term gonococcal infection. Viable gonococci and chlamydiae were recovered for an average of 8 to 10 days, and diplococci and chlamydial inclusions were observed in lower genital tract tissue by immunohistochemical staining. Estradiol treatment reduced proinflammatory cytokine and chemokine levels in chlamydia-infected mice; however, coinfected mice had a higher percentage of vaginal neutrophils compared to mice infected with either pathogen alone. We detected no difference in pathogen-specific antibody levels due to coinfection. Interestingly, significantly more gonococci were recovered from coinfected mice compared to mice infected with N. gonorrhoeae alone. We found no evidence that C. muridarum increases gonococcal adherence to, or invasion of, immortalized murine epithelial cells. However, increased vaginal concentrations of inflammatory mediators macrophage inflammatory protein 2 and tumor necrosis factor alpha were detected in C. muridarum-infected mice prior to inoculation with N. gonorrhoeae concurrently with the downregulation of cathelicidin-related antimicrobial peptide and secretory leukocyte peptidase inhibitor genes. We conclude that female mice can be successfully infected with both C. muridarum and N. gonorrhoeae and that chlamydia-induced alterations in host innate responses may enhance gonococcal infection.

High-risk sexual behaviours and genital chlamydial infections in high school students in Southern Taiwan

Summary

The objective of this study was to determine the prevalence of high-risk sexual behaviours and sexually transmitted infections (STIs) and associated risk factors in Taiwanese high school students. Students in grades 10 and 11 (mean age: 15.9 ± 0.9; range: 13–20 years) at two schools were recruited. An anonymous online real-time computer-assisted self-interviewing questionnaire was designed to assess demographic factors and sexual behaviours. Urine specimens were tested for genital chlamydial and gonococcal infections. The same survey and screening was conducted one year later on the same group of students. Overall, 670 individual students (993 visits) were enrolled with 323 students in both surveys. Twenty-seven percent had had sexual intercourse, and more than three quarters (79%) of them had engaged in high-risk sexual behaviours. Having friends using drugs increased the odds of practicing high-risk sexual behaviours (odds ratio [OR] 1.99, 95% CI: 1.13 to 3.50). Among 182 sexually active students, 8.8% had chlamydial (female: 12.5%; male: 5.3%) and 1.1% had gonococcal infections. Having sex with someone met on the Internet was the most significant risk factor for acquiring chlamydia (OR 8.14, 95% CI: 2.82 to 23.51). In conclusion, this adolescent population reported high prevalence of high-risk sexual behaviours and had a high prevalence of chlamydia supportive of a potential epidemic of STIs and HIV.

Using spatial regression methods to examine the association between county-level racial/ethnic composition and reported cases of Chlamydia and gonorrhea: an illustration with data from the state of Texas

BACKGROUND

Several studies have reported racial/ethnic disparities in the incidence of sexually transmitted diseases. However, very few studies have accounted for potential spatial dependence. Additionally, little is known about the relative magnitudes of the associations between county-level racial/ethnic composition and the 2 most commonly reported sexually transmitted diseases.

METHODS

We used county-level data from the National Electronic Telecommunications System for Surveillance and the 2000 Census data to investigate the association between county-level racial/ethnic composition and reported cases of the 2 most commonly reported sexually transmitted diseases (chlamydia and gonorrhea) in Texas. We also estimated ordinary least square (OLS) models for comparison.

RESULTS

Preliminary results from the spatial regression models indicated that the choice of spatial relationships criteria was important for model specification. The spatial error model (SEM) was superior to the spatial autoregressive model, spatial Durbin model, and OLS. The SEM for the 2 disease equations were further analyzed using a seemingly unrelated regression estimation (SURE) procedure. Although the SEM was superior to all models (using standard criteria), the coefficients were fairly stable across models. Our results showed that a unit change in percent black was associated with 1.6 (1.1 for Hispanic) and 3.3 (0.5 for Hispanic) percent change in chlamydia and gonorrhea rates (on average), respectively, compared with percent white.

CONCLUSION

Although there were no substantial differences in the magnitude of the estimated parameters, spatial regression models are potentially superior to OLS models and should be explored in future sexually transmitted disease studies.

Chlamydia trachomatis positivity rates among men tested in selected venues in the United States: a review of the recent literature

The cost-effectiveness of screening men for Chlamydia trachomatis depends in part on the prevalence of chlamydia in the screened population and the ease with which screening programs can be implemented. Screening in venues with high rates of chlamydia positivity among men may therefore be an important adjunct to chlamydia control. To evaluate the recent US literature on chlamydia positivity in chlamydia screening programs among asymptomatic men in nonsexually transmitted disease clinic settings, we reviewed published articles between 1995 and June 2007, using PubMed as the primary search tool. Articles were abstracted and positivity rates summarized by type of venue, race/ethnicity, age group, and US region. The overall median positivity rate was 5.1%. The highest rates were observed among men tested in juvenile (7.9%) and adult (6.8%) detention facilities, among blacks (6.7%), the 15 to 19 years old (6.1%) and 20 to 24 years old (6.5%) age groups, and among men screened in the southern United States (6.4%). Chlamydia rates among men are high in certain venues, particularly correctional settings, but also depend on the demographic composition of the target population and location. Programs considering male chlamydia screening programs should conduct pilot programs to assess chlamydia positivity as well as feasibility and cost in target venues.

Cost-effectiveness of screening strategies for Chlamydia trachomatis using cervical swabs, urine, and self-obtained vaginal swabs in a sexually transmitted disease clinic setting

BACKGROUND

We evaluated the cost-effectiveness of Chlamydia screening strategies that use different methods of specimen collection: cervical swabs, urines, and self-obtained vaginal swabs.

METHODS

A decision analysis was modeled for a hypothetical cohort of 10,000 per year of women attending sexually transmitted disease (STD) clinics. Incremental cost-effectiveness of 4 screening strategies were compared: 1) Endocervical DNA probe test (PACE2, Gen-Probe), 2) Endocervical AC2 (Aptima Combo 2, Gen-Probe), 3) Self-Obtained Vaginal AC2, and 4) Urine AC2. Sensitivities of the vaginal, urine, and cervical AC2 tests were derived from 324 women attending STD clinics. The primary outcome was cases of pelvic inflammatory disease prevented. The model incorporated programmatic screening and treatment costs and medical cost savings from sequelae prevented.

RESULTS

Chlamydia prevalence in the sampled population was 11.1%. Sensitivities of vaginal, urine, and cervical AC2 were 97.2%, 91.7%, and 91.7%, respectively. The sensitivity of the DNA probe was derived from the literature and estimated at 68.8%. The self-obtained vaginal AC2 strategy was the least expensive and the most cost-effective, preventing 17 more cases of pelvic inflammatory disease than the next least expensive strategy.

CONCLUSIONS

Use of a vaginal swab to detect Chlamydia in this STD clinic population was cost-saving and cost-effective.

Formulas for estimating the costs averted by sexually transmitted infection (STI) prevention programs in the United States

Background

Sexually transmitted infection (STI) prevention programs can mitigate the health and economic burden of STIs. A tool to estimate the economic benefits of STI programs could prove useful to STI program personnel.

Methods

We developed formulas that can be applied to estimate the direct medical costs and indirect costs (lost productivity) averted by STI programs in the United States. Costs and probabilities for these formulas were based primarily on published studies.

Results

We present a series of formulas that can be used to estimate the economic benefits of STI prevention (in 2006 US dollars), using data routinely collected by STI programs. For example, the averted sequelae costs associated with treating women for chlamydia is given as (C_w)(0.16)(0.925)(0.70)($1,995), where C_w is the number of infected women treated for chlamydia, 0.16 is the absolute reduction in the probability of pelvic inflammatory disease (PID) as a result of treatment, 0.925 is an adjustment factor to prevent double-counting of PID averted in women with both chlamydia and gonorrhea, 0.70 is an adjustment factor to account for the possibility of re-infection, and $1,995 is the average cost per case of PID, based on published sources.

Conclusion

The formulas developed in this study can be a useful tool for STI program personnel to generate evidence-based estimates of the economic impact of their program and can facilitate the assessment of the cost-effectiveness of their activities.

Should asymptomatic men be included in chlamydia screening programs? Cost-effectiveness of chlamydia screening among male and female entrants to a national job training program

OBJECTIVE

To compare the cost-effectiveness of various chlamydia screening strategies within a population of male and female youth entering a national job training program.

STUDY DESIGN

Cost-effectiveness analysis of various chlamydia screening strategies among a cohort of 4000 female and male New England job training students. Strategies for women include (a) no screening, (b) universal endocervical DNA probe screening, (c) universal urine based NAAT screening, and (d) universal endocervical NAAT screening. Strategies for men include (a) no screening, (b) selective urine NAAT screening of leukocyte esterase (LE)-positive urines, and (c) universal urine-based NAAT screening.

RESULTS

Universal endocervical NAAT screening of women and universal urine NAAT screening of men were the most effective and cost-effective strategies individually and in combination. Endocervical NAAT screening of women prevented 23 more cases of PID and saved $27,000 more than endocervical DNA probe screening. Likewise, universal urine NAAT screening of men prevented 21 more cases of PID in their female partners and saved $16,000 more than selective urine NAAT screening of LE positive men.

CONCLUSIONS

Use of a sensitive NAAT to screen both men and women for chlamydia upon entry to a National Job Training Program is cost-effective, cost-saving, and provides a public health opportunity to substantially reduce chlamydia infections among youth at risk for sexually transmitted diseases.

Chlamydia trachomatis-associated tubal factor subfertility: Immunogenetic aspects and serological screening

Chlamydia (C.) trachomatis female genital tract infections usually remain asymptomatic and untreated. Therefore, an adequate immune response, rather than antibiotic treatment, is essential to clear the pathogen. Most women will effectively clear C. trachomatis infections, but some will have persistent C. trachomatis infections, which may ascend to the upper genital tract and increase the risk of tubal factor subfertility. Pattern recognition receptors (PRRs) of the toll-like receptor (TLR) and nucleotide-binding oligomerization domain (NOD) families recognize C. trachomatis and initiate the immune response. Host immune factors are determinants of the course of C. trachomatis infections. Genetic variations in TLR and NOD genes may affect receptor function, leading to inadequate recognition of C. trachomatis, an inadequate immune response, and consequently an increased risk of persistence and late sequelae. For the risk assessment of tubal pathology in subfertile women, C. trachomatis immunoglobulin (Ig) G antibody testing (CAT) in serum is widely used. A positive CAT is indicative of a previous infection but not of a persistent infection. Measuring serological markers of persistence, of which C-reactive protein (CRP) seems promising, in CAT-positive women may identify a subgroup of subfertile women with persistent C. trachomatis infections and the highest risk of tubal pathology.

Innovative Approaches to the Prevention and Control of Bacterial Sexually Transmitted Infections

Bacterial STI continues to be a major problem in developed nations. Research and evolving standards of public health practice are cause for optimism and concern. Innovations in case-finding and treatment, particularly the application of NAATs to test for chlamydial infection in nonclinical settings, are successes that merit more widespread application. EPT, selective STI screening in men, and rescreening are all promising, but are not yet in widespread use and may face significant operational barriers. To date, public health efforts to alter sexual behavior, at least through specific interventions, are more discouraging. Although some behavioral interventions have been effective, none has been widely instituted. Moreover, the likelihood that existing behavioral interventions will be widely applied seems remote. Future research efforts in this area will need to focus less on proof-of-concept efficacy trials and more on developing and testing sustainable, cost-effective interventions that focus on those at greatest risk and that can be scaled-up within the existing public health infrastructure.