Development and validation of multiplex assays for mouse and human IgG and IgA to Neisseria gonorrhoeae antigens

There is an urgent need for vaccines against Neisseria gonorrhoeae (Ng), the causative agent of gonorrhea. Vaccination with an outer-membrane vesicle (OMV)-based Neisseria meningitidis (Nm) vaccine provides some protection from Ng; however, the mechanisms underlying this cross-protection are unknown. To address this need, we developed multiplexed bead-based assays for the relative quantification of human and mouse IgG and IgA against Ng antigens. The assays were evaluated for analyte independence, dilutional linearity, specificity, sensitivity, intra- and inter-assay variability, and robustness to sample storage conditions. The assay was then used to test samples from mice and humans immunized with an Nm-OMV vaccine.

Evaluation of self-directed specimen collection for chlamydia and gonorrhea testing among people who use drugs

Background: People who use drugs (PWUD) often have elevated sexually transmitted infection (STI) risk and unmet healthcare needs. Self-directed STI specimen collection (i.e., individuals collect the specimen and mail to the laboratory) may be valuable in addressing STI testing barriers among PWUD. Methods: Within a cohort study among PWUD in New York City, we conducted a cross-sectional substudy from November 2021-August 2022 assessing sexual health with a one-time online survey (n = 120); participants could opt-in to receive a self-collection kit. Participants who opted-in were mailed a kit containing collection materials (males: urine cup, females: vaginal swab), pre-paid return label, instructions, and educational information. Specimens were sent to the laboratory and tested for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC). We measured the number of kits requested, delivered, mailed to the lab, and CT/GC positive; and examined differences in requesting a kit by sociodemographic and behavioral characteristics. Results: Sixty-three total kits were requested by 44 unique participants. Of the 63 requested, 41 were delivered; one kit was undeliverable at the provided address and the rest were not sent due to no address provided or being duplicate requests. Of the 41 kits delivered, three participants returned the kit to the lab; of those, one was positive for CT and GC. The greatest differences in those who did and did not request a kit were observed by age, sexual orientation, past-year sex trade and casual partnerships, and experiences of relationship violence. Conclusions: Self-directed specimen collection may be desirable for PWUD, but research is needed to understand barriers to this testing approach for this population.

Neisseria gonorrhoeae MtrCDE Efflux Pump During In Vivo Experimental Genital Tract Infection in Men and Mice Reveals the Presence of Within-Host Colonization Bottleneck

The MtrCDE efflux pump of Neisseria gonorrhoeae exports a wide range of antimicrobial compounds that the gonococcus encounters at mucosal surfaces during colonization and infection. Here, we evaluate the role of this efflux pump system in strain FA1090 in human male urethral infection with a Controlled Human Infection Model. Using the strategy of competitive multi-strain infection with wild-type FA1090 and an isogenic mutant strain that does not contain a functional MtrCDE pump, we found that the presence of the efflux pump during human experimental infection did not confer a competitive advantage. This finding is in contrast to previous findings in female mice, which demonstrated that gonococci of strain FA19 lacking a functional MtrCDE pump had a significantly reduced fitness compared to the wild type strain in the lower genital tract of female mice. We conducted competitive infections in female mice with FA19 and FA1090 strains, including mutants that do not assemble a functional Mtr efflux pump, demonstrating the fitness advantage provided byt the MtrCDE efflux pump during infection of mice is strain dependent. Our data indicate that new gonorrhea treatment strategies targeting the MtrCDE efflux pump functions may not be universally efficacious in naturally occurring infections. Owing to the equal fitness of FA1090 strains in men, our experiments unexpectedly demonstrated the likely presence of an early colonization bottleneck of N. gonorrhoeae in the human male urethra.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03840811 .

Gentamicin Susceptibility in Neisseria gonorrhoeae and Treatment Outcomes for Urogenital Gonorrhea After 25 Years of Sustained Gentamicin Use in Malawi

BACKGROUND

Gentamicin has been used for the treatment of gonorrhea in Malawi since 1993. However, declining clinical cure rates have been suspected. We evaluated current Neisseria gonorrhoeae susceptibility to gentamicin in vitro and clinically.

METHODS

Men with acute urethritis were recruited at the Bwaila District Hospital STI Clinic in Lilongwe, Malawi, between January 2017 and August 2019. All men provided urethral swabs for etiological testing at enrollment and test of cure (TOC), 1 week later, using Gram-stained microscopy and culture. We used Etest to determine minimum inhibitory concentrations (MICs) of gentamicin, azithromycin, cefixime, ceftriaxone, ciprofloxacin, and spectinomycin; disc diffusion for tetracycline susceptibility; and whole-genome sequencing (WGS) to verify/refute treatment failure.

RESULTS

Among 183 N. gonorrhoeae culture-positive men enrolled, 151 (82.5%) had a swab taken for TOC. Of these 151 men, 16 (10.6%) had a positive culture at TOC. One hundred forty-one baseline isolates were tested for gentamicin susceptibility using Etest: 2 (1.4%), MIC = 2 μg/mL; 111 (78.7%), MIC = 4 μg/mL; and 28 (19.9%), MIC = 8 μg/mL. All isolates were susceptible to azithromycin, cefixime, ceftriaxone, and spectinomycin, whereas 63.1% had intermediate susceptibility or resistance to ciprofloxacin. Almost all (96.1%) isolates were resistant to tetracycline. All examined isolates cultured at TOC (n = 13) had gentamicin MICs ≤8 μg/mL. Ten men had pretreatment and posttreatment isolates examined by whole-genome sequencing; 2 (20%) were verified new infections (4119 and 1272 single-nucleotide polymorphisms), whereas 8 (80%) were confirmed treatment failures (0-1 single-nucleotide polymorphism).

CONCLUSIONS

Gentamicin MICs poorly predict gonorrhea treatment outcome with gentamicin, and treatment failures are verified with gonococcal strains with in vitro susceptibility to gentamicin. The first-line treatment of gonorrhea in Malawi should be reassessed.

Experimental Urethral Infection with Neisseria gonorrhoeae

Gonorrhea rates and antibiotic resistance are both increasing. Neisseria gonorrhoeae (Ng) is an exclusively human pathogen and is exquisitely adapted to its natural host. Ng can subvert immune responses and undergoes frequent antigenic variation, resulting in limited immunity and protection from reinfection. Previous gonococcal vaccine efforts have been largely unsuccessful, and the last vaccine to be tested in humans was more than 35 years ago. Advancing technologies and the threat of untreatable gonorrhea have fueled renewed pursuit of a vaccine as a long-term sustainable solution for gonorrhea control. Despite the development of a female mouse model of genital gonococcal infection two decades ago, correlates of immunity or protection remain largely unknown, making the gonococcus a challenging vaccine target. The controlled human urethral infection model of gonorrhea (Ng CHIM) has been used to study gonococcal pathogenesis and the basis of anti-gonococcal immunity. Over 200 participants have been inoculated without serious adverse events. The Ng CHIM replicates the early natural course of urethral infection. We are now at an inflexion point to pivot the use of the model for vaccine testing to address the urgency of improved gonorrhea control. Herein we discuss the need for gonorrhea vaccines, and the advantages and limitations of the Ng CHIM in accelerating the development of gonorrhea vaccines.

What's Sex Got to Do With It? Understanding Potential Confounding and Exposure Misclassification in Mechanistic Sexually Transmitted Infection Research

We conducted a prospective study of 13 heterosexual couples to understand the impact of recent condomless vaginal sex on vaginal immune marker measurement and potential exposure misclassification due to the presence of semen. All immune markers were detectable in semen and concentrations of vaginal immune markers varied by sex recency.

Experimental Human Infection with Neisseria gonorrhoeae

Experimental infection of male volunteers with Neisseria gonorrhoeae is safe and reproduces the clinical features of naturally acquired gonococcal urethritis. The human model is useful for testing the importance of putative gonococcal virulence factors for urethral infection in men and the model presents opportunities to examine host immune responses that may be exploited or improved in development and testing of gonococcal vaccines. In this chapter, we describe methods for production, characterization, and storage of N. gonorrhoeae stocks for experimental human challenge, preparation and delivery of inoculum suspensions, monitoring experimental infection, and statistical considerations for data analysis.

Home Self-Collection by Mail to Test for Human Papillomavirus and Sexually Transmitted Infections

OBJECTIVE

To evaluate the validity and acceptability of at-home self-collection to test for high-risk human papillomavirus (HPV) and sexually transmitted infections among women overdue for cervical cancer screening by national guidelines.

METHODS

Low-income, infrequently screened women were recruited from the general population in North Carolina to participate in an observational study. Participants provided two self-collected cervicovaginal samples (one at home and one in the clinic) and a clinician-collected cervical sample. Samples were tested for high-risk HPV, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Mycoplasma genitalium. Cervical samples were also tested by liquid-based cytology.

RESULTS

Overall, 193 women had conclusive high-risk HPV results for all three samples and cytology results. Prevalence of high-risk HPV within self-home samples (12.4%) was not different from that within clinician samples (11.4%; P=.79) and from that within self clinic samples (15.5%; P=.21). Positivity for high-risk HPV in all sample types increased with increasing grades of cervical abnormality (P<.001). Self-home samples detected high-risk HPV in all identified cases of high-grade squamous intraepithelial lesions and of cervical intraepithelial neoplasia 2 or worse. Detection was comparable across sample types for T vaginalis (range 10.2-10.8%), M genitalium (3.3-5.5%), C trachomatis (1.1-2.1%), and N gonorrhoeae (0-0.5%). Kappa values between sample types ranged from 0.56 to 0.66 for high-risk HPV, 0.86-0.91 for T vaginalis, and 0.65-0.83 for M genitalium. Most participants reported no difficulty understanding self-collection instructions (93.6%) and were willing to use self-collection in the future (96.3%).

CONCLUSION

Mail-based, at-home self-collection for high-risk HPV and sexually transmitted infection detection was valid and well accepted among infrequently screened women in our study. These findings support the future use of high-risk HPV self-collection to increase cervical cancer screening rates among higher risk women in the United States.

A Silent Epidemic: The Prevalence, Incidence and Persistence of Mycoplasma genitalium Among Young, Asymptomatic High-Risk Women in the United States

Background

Mycoplasma genitalium can result in pelvic inflammatory disease and adverse pregnancy outcomes. We analyzed data collected from a prospective study of asymptomatic bacterial vaginosis (BV) to determine the natural history of M. genitalium.

Methods

Women aged 15-25 years, with asymptomatic BV and ≥2 risk factors for sexually transmitted infection were recruited from 10 sites throughout the United States. Vaginal swab samples were collected at enrollment and through home-based testing every 2 months over 12 months. M. genitalium nucleic acid amplification testing was performed for M. genitalium using transcription-mediated assays (Hologic). The prevalence, incidence, and persistence of M. genitalium, defined as all positive specimens during follow-up, were estimated with 95% confidence intervals (CIs). Adjusted odds ratios (AOR) were calculated using logistic and Poisson regression to evaluate participant characteristics associated with M. genitalium infection.

Results

Among 1139 women, 233 were M. genitalium positive, for a prevalence of 20.5% (95% CI, 18.2%-22.9%); 42 of 204 had persistent M. genitalium (20.6%). Among 801 M. genitalium-negative women at baseline, the M. genitalium incidence was 36.6 per 100 person-years (95% CI, 32.4-41.3). Black race (AOR, 1.92; 95% CI, 1.09-3.38), age ≤21 years (1.40; 1.03-1.91), and prior pregnancy (1.36; 1.00-1.85) were associated with prevalent M. genitalium; only black race was associated with incident M. genitalium (P = .03).

Conclusions

We identified high rates of prevalent, incident, and persistent M. genitalium infections among young, high-risk women with asymptomatic BV, supporting the need for clinical trials to evaluate the impact of M. genitalium screening on female reproductive health outcomes.

Experimental vaccine induces Th1-driven immune responses and resistance to Neisseria gonorrhoeae infection in a murine model

Female mice were immunized intravaginally with gonococcal outer membrane vesicles (OMVs) plus microencapsulated interleukin-12 (IL-12), and challenged using an established model of genital infection with Neisseria gonorrhoeae. Whereas sham-immunized and control animals cleared the infection in 10-13 days, those immunized with OMV plus IL-12 cleared infection with homologous gonococcal strains in 6-9 days. Significant protection was also seen after challenge with antigenically distinct strains of N. gonorrhoeae, and protective anamnestic immunity persisted for at least 6 months after immunization. Serum and vaginal immunoglobulin G (IgG) and IgA antibodies were generated against antigens expressed by homologous and heterologous strains. Iliac lymph node CD4⁺ T cells secreted interferon-γ (IFNγ), but not IL-4, in response to immunization, and produced IL-17 in response to challenge regardless of immunization. Antigens recognized by immunized mouse serum included several shared between gonococcal strains, including two identified by immunoproteomics approaches as elongation factor-Tu (EF-Tu) and PotF3. Experiments with immunodeficient mice showed that protective immunity depended upon IFNγ and B cells, presumably to generate antibodies. The results demonstrated that immunity to gonococcal infection can be induced by immunization with a nonliving gonococcal antigen, and suggest that efforts to develop a human vaccine should focus on strategies to generate type 1 T helper cell (Th1)-driven immune responses in the genital tract.

Sexual Relationship Power and Semen Exposure Among Female Patients at a Sexually Transmitted Infection Clinic in Kingston, Jamaica

Women's power in sexual relationships is thought to be an important predictor of condom use. However, research on correlates of condom use often relies on participant reporting of behavior, which has questionable validity. We evaluated the association between scores from the modified Sexual Relationship Power Scale (SRPS-M) and biological detection of semen exposure in a prospective study of adult women attending a sexually transmitted infection clinic in Kingston, Jamaica with cervicitis or abnormal vaginal discharge in 2010-2011. At enrollment, women were counseled to avoid sex while on treatment and were asked to return in 6 days for a follow-up visit. At both study visits, women were administered a questionnaire and had vaginal swabs collected to test for prostate-specific antigen (PSA), a biological marker of recent semen exposure. We found no significant association at enrollment or follow-up between SRPS-M scores and semen exposure, as measured with either self-reported data or PSA positivity. Semen biomarkers could be used to develop and validate new scales on relationship power and self-efficacy related to condom use.

Vaginal Prostate Specific Antigen (PSA) Is a Useful Biomarker of Semen Exposure Among HIV-Infected Ugandan Women

The practical feasibility of using prostate specific antigen (PSA) as a biomarker of semen exposure was examined among HIV-infected Ugandan women. Vaginal fluids were obtained with self-collected swabs and a qualitative rapid test (ABAcard^®p30) was used to detect PSA. Trained laboratory technicians processed samples on-site and positive PSA tests were compared to self-reported unprotected vaginal sex (UVS) in the last 48 h. A total of 77 women submitted 126 samples for PSA testing at up to three study visits. Of these samples, 31 % (n = 39/126) were PSA positive, and 64 % (n = 25/39) of the positive PSA samples were accompanied by self-report of no UVS at the study visit the PSA was collected. There were no reported difficulties with specimen collection, storage, or processing. These findings provide preliminary data on high levels of misreported UVS among HIV-infected Ugandan women using practically feasible methods for PSA collection and processing.

Validation of the Cepheid GeneXpert for Detecting Ebola Virus in Semen

BACKGROUND

Ebola virus (EBOV) RNA persistence in semen, reported sexual transmission, and sporadic clusters at the end of the 2013-2016 epidemic have prompted recommendations that male survivors refrain from unprotected sex unless their semen is confirmed to be EBOV free. However, there is no fully validated assay for EBOV detection in fluids other than blood.

METHODS

The Cepheid Xpert Ebola assay for EBOV RNA detection was validated for whole semen and blood using samples obtained from uninfected donors and spiked with inactivated EBOV. The validation procedure incorporated standards from Clinical and Laboratory Standards Institute and Good Clinical Laboratory Practices guidelines for evaluating molecular devices for use in infectious disease testing.

RESULTS

The assay produced limits of detection of 1000 copies/mL in semen and 275 copies/mL in blood. Limits of detection for both semen and blood increased with longer intervals between collection and testing, with acceptable results obtained up to 72 hours after specimen collection.

CONCLUSIONS

The Cepheid Xpert Ebola assay is accurate and precise for detecting EBOV in whole semen. A validated assay for EBOV RNA detection in semen informs the care of male survivors of Ebola, as well as recommendations for public health.

A Review of Evidence-Based Care of Symptomatic Trichomoniasis and Asymptomatic Trichomonas vaginalis Infections

Trichomonas vaginalis is the most prevalent nonviral sexually transmitted infection, affecting an estimated 3.7 million women and men in the United States. Health disparities are prominent in the epidemiology of this infection, which affects 11% of women aged ≥40 years and a disproportionately high percentage of black women. Particularly high prevalences have been identified among sexually transmitted disease (STD) clinic patients and incarcerated individuals. This article reviews and updates scientific evidence in key topic areas used for the development of the 2015 STD Treatment Guidelines published by the Centers for Disease Control and Prevention. Current evidence is presented regarding conditions associated with Trichomonas vaginalis infection, including human immunodeficiency virus (HIV) and pregnancy complications such as preterm birth. Nucleic acid amplification tests and point-of-care tests are newly available diagnostic methods that can be conducted on a variety of specimens, potentially allowing highly sensitive testing and screening of both women and men at risk for infection. Usually, trichomoniasis can be cured with single-dose therapy of an appropriate nitroimidazole antibiotic, but women who are also infected with HIV should receive therapy for 7 days. Antimicrobial resistance is an emerging concern.

Disclosure of HSV-2 serological test results in the context of an adolescent HIV prevention trial in Kenya

OBJECTIVES

Herpes simplex virus type 2 (HSV-2) biomarkers are often used in adolescent sub-Saharan HIV prevention studies, but evaluations of test performance and disclosure outcomes are rare in the published literature. Therefore, we investigated the proportion of ELISA-positive and indeterminate samples confirmed by western blot (WB), the psychosocial response to disclosure and whether reports of sexual behaviour and HSV-2 symptoms are consistent with WB confirmatory results among adolescent orphans in Kenya.

METHODS

In 2011, 837 Kenyan orphan youth in grades 7 and 8 enrolled in an HIV prevention clinical trial with HSV-2 biomarker outcomes. We used a modified algorithm for the Kalon HSV-2 ELISA to improve specificity; positive and indeterminate results were WB tested. We developed culturally sensitive protocols for disclosing positive results, and documented psychosocial responses, reports of sexual contact and HSV-2 symptoms.

RESULTS

28 adolescents (3.3%) were identified as HSV-2 seropositive, six as indeterminate. Of these, 22 positive and all indeterminates were WB tested; 20 and 5, respectively, were confirmed positive. Most youth reported moderate brief stress after disclosure; 22% reported longer and more severe distress. Boys were more likely to be in the latter category. Self-reported virginity was highly inconsistent with WB-confirmed positives.

CONCLUSIONS

The higher than manufacturer's cut-off for Kalon ELISA modestly reduced the rate of false-positive test results, but also increased false negatives. Investigators should consider the risk:benefit ratio in deciding whether or not to disclose HSV-2 results to adolescent participants under specific field conditions.

TRIAL REGISTRATION NUMBER

NCT01501864.

Understanding the high prevalence of HIV and other sexually transmitted infections among socio-economically vulnerable men who have sex with men in Jamaica

OBJECTIVES

This study estimates HIV prevalence among men who have sex with men (MSM) in Jamaica and explores social determinants of HIV infection among MSM.

DESIGN

An island-wide cross-sectional survey of MSM recruited by peer referral and outreach was conducted in 2011. A structured questionnaire was administered and HIV/STI tests done. We compared three groups: MSM who accepted cash for sex within the past 3 months (MSM SW), MSM who did not accept cash for sex (MSM non-SW), and MSM with adverse life events (ever raped, jailed, homeless, victim of violence or low literacy).

RESULTS

HIV prevalence among 449 MSM was 31.4%, MSM SW 41.1%, MSM with adverse life events 38.5%, 17 transgender MSM (52.9%), and MSM non-SW without adverse events 21.0%. HIV prevalence increased with age and number of adverse life events (test for trend P < 0.001), as did STI prevalence (P = 0.03). HIV incidence was 6.7 cases/100 person-years (95% CI: 3.74, 12.19). HIV prevalence was highest among MSM reporting high-risk sex; MSM SW who had been raped (65.0%), had a STI (61.2%) and who self identified as female (55.6%). Significant risk factors for HIV infection common to all 3 subgroups were participation in both receptive and insertive anal intercourse, high-risk sex, and history of a STI. Perception of no or little risk, always using a condom, and being bisexual were protective.

CONCLUSION

HIV prevalence was high among MSM SW and MSM with adverse life events. Given the characteristics of the sample, HIV prevalence among MSM in Jamaica is probably in the range of 20%. The study illustrates the importance of social vulnerability in driving the HIV epidemic. Programs to empower young MSM, reduce social vulnerability and other structural barriers including stigma and discrimination against MSM are critical to reduce HIV transmission.

"Do you think your main partner has other sex partners?" A simple question provides insight into sexual risk in Jamaica

To estimate the association between a simple measure of sexual partner concurrency and sexually transmitted infection (STI) we conducted a cross-sectional population-based household survey (n = 1795) and targeted surveys of people at venues where people meet sexual partners (n = 1580) to ask about sexual behaviour. Persons interviewed at venues were tested for HIV, gonorrhoea, chlamydia, and trichomoniasis. We compared the association between STI and reporting a partner had other partners. More women than men reported their main partner had other partners. Thirteen percent of all women in the population-based survey and 14.4% in the targeted survey reported having one partner in the past 12 months and that partner had additional partners. STI prevalence was significantly associated with reporting a partner had other partners (36.8% vs. 30.2%; prevalence ratio [PR] 1.2; 95% confidence interval [CI] 1.1, 1.4). Construction of complete sexual networks is costly and not routinely feasible. We recommend adding a question to cross-sectional surveys used to monitor sexual behaviour about whether the respondent believes his or her partner has other sexual partners. Although subject to bias, the question was useful in Jamaica to identify a group of women with only one sexual partner at increased risk of infection.

Antimicrobial susceptibility and molecular typing of MRSA in cystic fibrosis

OBJECTIVES

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients in the United States is approximately 25%. Little is known about the relative proportion of hospital- versus community-associated strains or the antimicrobial susceptibility of MRSA in different CF centers. We hypothesized that the majority of MRSA isolates obtained from children with CF are those endemic in the hospital and that those associated with community acquisition (SCCmec IV) would be more resistant than typically seen in non-CF MRSA isolates.

METHODS

We studied MRSA strains from seven pediatric CF centers to determine the clonal distribution based on DNA sequencing of the staphylococcal protein A gene (spa typing), the type of staphylococcal chromosomal cassette mec (SCCmec), and the proportion of strains with Panton-Valentine leukocidin (PVL). Antimicrobial susceptibility to systemic and topical antibiotics was compared between different MRSA types.

RESULTS

We analyzed 277 MRSA isolates from unique patients (mean age 11.15 ± 4.77 years, 55% male). Seventy % of isolates were SCCmec II PVL negative and the remainder SCCmec IV. Overall 17% MRSA strains were PVL positive (all SCCmec IV). Spa typing of 118 isolates showed most of the SCCmec II strains being t002, while SCCmec IV PVL positive isolates were t008, and SCCmec IV PVL negative isolates represented a variety of spa-types. The proportions of SCCmec II strains and spa-types were similar among centers. Overall rates of resistance to trimethoprim-sulfamethoxazole (4%), tetracycline (7%), tigecycline (0.4%), linezolid (0.4%) as well as fosfomycin (0.4%), fusidic acid (3%), and mupirocin (1%) were low. No strains were resistant to vancomycin. SCCmec II strains had higher rates of resistance to ciprofloxacin and clindamycin (P < 0.001) than SCCmec IV strains.

CONCLUSIONS

In this U.S. study, most MRSA isolates in the pediatric CF population were SCCmec II PVL negative. Rates of resistance were low, including to older and orally available antibiotics such as trimethoprim-sulfamethoxazole.

Modern diagnosis of Trichomonas vaginalis infection

Recent advances in tests for the sexually transmitted protozoan parasite Trichomonas vaginalis have increased opportunities for diagnosis and treatment of this important sexually transmitted infection. This review summarises currently available tests, highlighting their performance characteristics, advantages and limitations. The recent development of molecular tests for the detection of T vaginalis, including rapid antigen detection and nucleic acid amplification tests, has significantly improved the quality of diagnostics for trichomoniasis, particularly in women. In light of the expanded menu of testing options now available, improved recognition and better control of trichomoniasis are in sight, which should enable the eventual reduction of adverse reproductive consequences associated with T vaginalis infection.

Randomized controlled trial on the effectiveness of counseling messages for avoiding unprotected sexual intercourse during sexually transmitted infection and reproductive tract infection treatment among female sexually transmitted infection clinic patients

BACKGROUND

The effectiveness of counseling messages to avoid unprotected sex during short-term treatment for curable sexually transmitted infections is unknown.

METHODS

We randomized 300 female STI clinic patients 18 years or older with cervicitis and/or vaginal discharge in Kingston, Jamaica, in 2010 to 2011, to 1 of 2 counseling messages for their course of syndromic treatment: abstinence only or abstinence backed up by condom use. At a follow-up visit 6 days afterward, we collected vaginal swabs to test for prostate-specific antigen (PSA), a biological marker of recent semen exposure, and administered a questionnaire assessing sexual behavior.

RESULTS

No differences were found in the proportions of women testing positive for PSA at follow-up in the abstinence-plus-condom group (11.9%) and abstinence-only group (8.4%) (risk difference, 3.5; 95% confidence interval, -3.5 to 10.5). There also was no significant difference in reporting of unprotected sex between groups. Reporting a history of condom use before enrollment significantly modified the effect of counseling arm on PSA positivity (P = 0.03). Among those reporting recent condom use, 10.3% in the abstinence-only arm and 4.8% in the abstinence-plus-condom arm tested positive for PSA. Conversely, among those not reporting recent condom use, 6.5% in the abstinence-only arm and 17.3% in the abstinence-plus-condom arm had PSA detected.

CONCLUSIONS

We found no evidence to support the superiority of either counseling message. Post hoc analyses suggest that women with recent condom experience may benefit significantly more from abstinence-plus-condom messages, whereas women without such experience may benefit significantly more from abstinence-only messages. Providers should weigh individual condom use history when determining the most appropriate counseling message.

Modeling the impact of Trichomonas vaginalis infection on HIV transmission in HIV-infected individuals in medical care

BACKGROUND

To assess factors associated with having a Trichomonas vaginalis (TV) infection among persons receiving care for human immunodeficiency virus (HIV) and estimate the number of transmitted HIV infections attributable to TV.

METHODS

HIV clinic patients were recruited from 2 secondary prevention studies, screened by urine nucleic-acid amplification tests for sexually transmitted infections, and interviewed about risk factors (baseline, 6, and 12 months). We conducted mathematical modeling of the results to estimate the number of transmitted HIV infections attributable to TV among a cohort of HIV-infected patients receiving medical care in North Carolina.

RESULTS

TV was prevalent in 7.4%, and incident in 2% to 3% of subjects at follow-up. Individuals with HIV RNA <400 copies/mL (odds ratio, 0.32; 95% CI: 0.14-0.73) and at least 13 years of education (odds ratio, 0.24; 95% CI: 0.08-0.70) were less likely to have TV. Mathematical modeling predicted that 0.062 HIV transmission events occur per 100 HIV-infected women in the absence of TV infection and 0.076 HIV infections per 100 HIV- and TV-infected women (estimate range: 0.070-0.079), indicating that 23% of the HIV transmission events from HIV-infected women may be attributable to TV infection when 22% of women are coinfected with TV.

CONCLUSIONS

The data suggest the need for improved diagnosis of TV infection and suggest that HIV-infected women in medical care may be appropriate targets for enhanced testing and treatment.

Trichomonas vaginalis genital infections: progress and challenges

Trichomonas vaginalis (TV) infection is the most prevalent curable sexually transmitted infection in the United States and worldwide. Most TV infections are asymptomatic, and the accurate diagnosis of this infection has been limited by lack of sufficiently sensitive and specific diagnostic tests, particularly for men. To provide updates for the 2010 Centers for Disease Control and Prevention's Sexually Transmitted Diseases Treatment Guidelines, a PubMed search was conducted of all TV literature published from 9 January 2004 through 24 September 2008. Approximately 175 pertinent abstracts and articles were reviewed and discussed with national experts. This article describes advances in TV diagnostics which have led to an improved understanding of the epidemiology of this pathogen, as well as potential biologic and epidemiological interactions between TV and human immunodeficiency virus (HIV). New data on treatment outcomes, metronidazole-resistant TV, management of nitroimidazole-allergic patients, frequency of recurrent TV infection following treatment, and screening considerations for TV in certain populations are also presented.

Molecular testing for Trichomonas vaginalis in women: results from a prospective U.S. clinical trial

Trichomoniasis is a common sexually transmitted disease associated with preterm birth, low birth weight, and increased susceptibility to infection with other pathogenic sexually transmitted microorganisms. Nucleic acid amplification tests for Trichomonas vaginalis have improved sensitivity for detecting infected individuals compared to existing culture-based methods. This prospective, multicenter U.S. clinical trial evaluated the performance of the automated Aptima T. vaginalis assay for detecting T. vaginalis in 1,025 asymptomatic and symptomatic women. Vaginal swab, endocervical swab, ThinPrep PreservCyt, and urine specimens were collected. Subject infection status was determined by wet-mount microscopy and culture. Aptima T. vaginalis assay performance was determined for each specimen type by comparison to subject infection status. Of 933 subjects analyzed, 59.9% were symptomatic. Aptima T. vaginalis clinical sensitivity and specificity were, respectively, 100% and 99.0% for vaginal swabs, 100% and 99.4% for endocervical swabs, 100% and 99.6% in ThinPrep samples, and 95.2% and 98.9% in urine specimens. Aptima T. vaginalis performance levels were similar in asymptomatic and symptomatic subjects. This study validates the clinical performance of the Aptima T. vaginalis assay for screening asymptomatic and symptomatic women for T. vaginalis infection.

Chlamydia trachomatis infection among 15- to 35-year-olds in Baltimore, MD

BACKGROUND

Chlamydia trachomatis (Ct) is the most frequently reported infectious disease in the United States. This article reports population and subpopulation prevalence estimates of Ct and correlates of infection among 15- to 35-year-olds in Baltimore, MD.

METHODS

The Monitoring STIs Survey Program (MSSP) monitored sexually transmitted infection (STI) prevalence among probability samples of residents of Baltimore, a city with high STI rates. MSSP respondents completed telephone audio computer-assisted self-interviews and provided biospecimens for STI testing.

RESULTS

Among 2120 Baltimore residents aged 15 to 35 years, the estimated prevalence of chlamydia was 3.9% (95% confidence interval [CI]: 2.8, 5.0). Prevalence was 5.8% (95% CI: 4.1, 7.6) among black MSSP respondents versus 0.7% (95% CI: 0.0, 1.4) among nonblack respondents; all but 4 infections detected were among black respondents. Sexual behaviors and other factors associated with infection were far more prevalent among black than nonblack Baltimore residents. Racial disparities persisted after adjustment for sociodemographic, behavioral, and health factors.

CONCLUSION

The MSSP highlights a higher Ct prevalence among young people in Baltimore than in the United States overall, with notable racial disparities in infection and associated risk behaviors. Public health efforts are needed to improve the diagnosis and treatment of asymptomatic infections in this population.

Experimental Gonococcal Infection in Male Volunteers: Cumulative Experience with Neisseria gonorrhoeae Strains FA1090 and MS11mkC

Experimental infection of male volunteers with Neisseria gonorrhoeae is safe and reproduces the clinical features of naturally acquired gonococcal urethritis. Human inoculation studies have helped define the natural history of experimental infection with two well-characterized strains of N. gonorrhoeae, FA1090 and MS11mkC. The human model has proved useful for testing the importance of putative gonococcal virulence factors for urethral infection in men. Studies with isogenic mutants have improved our understanding of the requirements for gonococcal LOS structures, pili, opacity proteins, IgA1 protease, and the ability of infecting organisms to obtain iron from human transferrin and lactoferrin during uncomplicated urethritis. The model also presents opportunities to examine innate host immune responses that may be exploited or improved in development and testing of gonococcal vaccines. Here we review results to date with human experimental gonorrhea.

Vaginal swab specimen processing methods influence performance of rapid semen detection tests: a cautionary tale

BACKGROUND

Detection of semen biomarkers in vaginal fluid can be used to assess women's recent exposure to semen. Quantitative tests for detection of prostate-specific antigen (PSA) perform well, but are expensive and require specialized equipment. We assessed two rapid immunochromatographic strip tests for identification of semen in vaginal swabs.

STUDY DESIGN

We tested 581 vaginal swabs collected from 492 women. Vaginal secretions were eluted into saline, and PSA was measured using the quantitative IMx (Abbott Laboratories, Abbott Park, IL, USA) assay. Specimens were also tested using the ABAcard p30 test (Abacus Diagnostics, West Hills, CA, USA) for detection of PSA and RSID-Semen test (Independent Forensics, Hillside, IL, USA) for detection of semenogelin (Sg).

RESULTS

Vaginal swab extraction using saline was compatible with direct assessment of vaginal swab eluates using ABAcard for PSA detection, but not for Sg detection using RSID. The rapid PSA test detected 91% of specimens containing semen compared to 74% by the rapid Sg test.

CONCLUSION

Investigators are urged to optimize vaginal swab specimen preparation methods for performance of RSID or other tests to detect semen components other than PSA. Previously described methods for PSA testing are not uniformly applicable to other tests.

Biomarker validation of reports of recent sexual activity: results of a randomized controlled study in Zimbabwe

Challenges in the accurate measurement of sexual behavior in human immunodeficiency virus (HIV) prevention research are well documented and have prompted discussion about whether valid assessments are possible. Audio computer-assisted self-interviewing (ACASI) may increase the validity of self-reported behavioral data. In 2006-2007, Zimbabwean women participated in a randomized, cross-sectional study that compared self-reports of recent vaginal sex and condom use collected through ACASI or face-to-face interviewing (FTFI) with a validated objective biomarker of recent semen exposure (prostate-specific antigen (PSA) levels). Of 910 study participants, 196 (21.5%) tested positive for PSA, an indication of semen exposure during the previous 2 days. Of these 196 participants, 23 (11.7%) reported no sex in the previous 2 days, with no difference in reported sexual activity between interview modes (12.5% ACASI vs. 10.9% FTFI; Fisher's exact test: P = 0.72). In addition, 71 PSA-positive participants (36.2%) reported condom-protected vaginal sex only; their reports also indicated no difference between interview modes (33.7% ACASI vs. 39.1% FTFI; P = 0.26). Only 52% of PSA-positive participants reported unprotected sex during the previous 2 days. Self-report was a poor predictor of recent sexual activity and condom use in this study, regardless of interview mode, providing evidence that such data should be interpreted cautiously.

Self-reported condom use is associated with reduced risk of chlamydia, gonorrhea, and trichomoniasis

OBJECTIVES

To evaluate the association between self-reported condom use and prevalent and incident chlamydia, gonorrhea, and trichomoniasis.

STUDY DESIGN

Prospective study of 414 males attending a sexually transmitted infection (STI) clinic in Jamaica. Condom use and STI status were assessed at enrollment and at 4 follow-up visits.

RESULTS

The analyses on condom use and prevalent STI included data from 414 men, while those on incident STI were based on 1111 intervals from 355 men. We diagnosed prevalent STI (chlamydia, gonorrhea, and/or trichomoniasis) in 54.6% (n = 226) of the participants at enrollment. About 14% (n = 51) of participants had at least 1 of the study STIs during follow-up. Follow-up visits in which participants reported consistent condom use (100% of acts) for the past 7 days had less incident STI (adjusted OR, 0.4; 95% CI, 0.2-0.9) compared with visits where no condom use was reported. Self-reported condom use was more closely correlated with incident than prevalent STI. For example, the adjusted OR for prevalent infection for participants reporting consistent versus no condom use in past 7 days was 0.7 (95% CI, 0.4-1.2). Classifications based on the number of unprotected acts yielded findings similar to those based on the proportion of acts protected.

CONCLUSIONS

Consistent condom use was associated with reduced risk of incident urethral STI. Research on condom effectiveness should focus on incident STI outcomes, where the temporal relationship between condom use and infection is clearer.

The association between Trichomonas vaginalis infection and level of vaginal lactobacilli, in nonpregnant women

The effect that vaginal lactobacilli have on trichomoniasis is not known. At 3 clinics for treatment of sexually transmitted disease, we recruited 521 female patients with trichomoniasis and 176 control subjects. All participants underwent physical examinations and testing for sexually transmitted infection and completed questionnaires. Low levels of vaginal lactobacilli were associated with trichomoniasis (odds ratio [OR], 2.2 [95% confidence interval {CI}, 1.4-3.2]). After adjustment for covariables, this association remained in women with a higher educational level (OR, 4.6 [95% CI, 2.2-9.5]) but not in women with a lower educational level (OR, 1.6 [95% CI, 0.7-3.4]). Vaginal lactobacilli may be associated with trichomoniasis in women with higher levels of education or a related behavioral factor.

Validity of self-reported 'safe sex' among female sex workers in Mombasa, Kenya--PSA analysis

We assessed the validity of self-reported sex and condom use by comparing self-reports with prostate-specific antigen (PSA) detection in a prospective study of 210 female sex workers in Mombasa, Kenya. Participants were interviewed on recent sexual behaviours at baseline and 12-month follow-up visits. At both visits, a trained nurse instructed participants to self-swab to collect vaginal fluid specimens, which were tested for PSA using enzyme-linked immunosorbent assay (ELISA). Eleven percent of samples (n = 329) from women reporting no unprotected sex for the prior 48 hours tested positive for PSA. The proportions of women with this type of discordant self-reported and biological data did not differ between the enrolment and 12-month visit (odds ratio [OR] 1.1; 95% confidence interval [CI] 0.99, 1.2). The study found evidence that participants failed to report recent unprotected sex. Furthermore, because PSA begins to clear immediately after exposure, our measures of misreported semen exposure likely are underestimations.

Rapid antigen testing compares favorably with transcription-mediated amplification assay for the detection of Trichomonas vaginalis in young women

BACKGROUND

Diagnosis of Trichomonas vaginalis (TV) infection is limited by imperfect testing methods. Newer tests, such as rapid antigen and nucleic acid amplification tests, are often compared with culture, which is not widely used but is more sensitive than wet mount. We assessed the sensitivity and specificity of 4 tests for the identification of TV using 3 statistical approaches.

METHODS

Sexually active adolescent women aged 14-21 years (n=330) were recruited from a teen health center and emergency department. Vaginal swabs were tested for TV using wet mount, culture (InPouch TV; Biomed Diagnostics), rapid antigen testing (OSOM TV; Genzyme Diagnostics), and transcription-mediated amplification testing (TMA; APTIMA TV analyte specific reagents; Gen-Probe).

RESULTS

TV was detected in 61 participants (18.5%). Compared with a composite reference standard (i.e., any TV test with positive results), the sensitivities of wet mount, culture, rapid antigen testing, and TMA were 50.8%, 75.4%, 82%, and 98.4%, respectively. Using latent class analysis, the sensitivity of wet mount (56%) was significantly lower than that of other tests, and the sensitivities of culture and rapid antigen testing were similar (83% and 90%, respectively); specificity was 100% for each of these 3 methods. TMA had a sensitivity of 98.2% and a specificity of 98%. Tests performed equally well regardless of whether the participant had bleeding or other infections. The sensitivities of the rapid antigen test and TMA were comparable (92.5% and 97.5%, respectively) in women who had vaginal symptoms.

CONCLUSIONS

Wet mount alone is insufficient for the reliable diagnosis of TV infection in women. TMA and rapid antigen tests are highly sensitive and specific, and both are superior to wet mount. Rapid antigen testing is equivalent to culture, and it compares favorably with the sensitivity of TMA for the detection of TV.

Randomised controlled trial on whether advance knowledge of prostate-specific antigen testing improves participant reporting of unprotected sex

OBJECTIVES

To determine whether the process of informing research participants that they would be tested for the presence of a biological marker of semen exposure would reduce bias in their reports of unprotected sex.

METHODS

A randomised trial of 210 female sex workers from Mombasa, Kenya, was conducted, where half the group had advance knowledge (via the request for informed consent) that they would be tested for prostate-specific antigen (PSA) in their vaginal fluid before they reported on sex and condom use for the past 48 h. The other half were invited to participate (via additional informed consent) in the test for PSA after they had already consented to be questioned and reported on these sexual behaviours. A trained nurse instructed participants to self-swab to collect vaginal fluid specimens, which were tested for PSA using ELISA.

RESULTS

Reporting of unprotected sex did not differ between those with advance knowledge of the test for PSA and those without this knowledge (14.3% v 11.4%, respectively; p = 0.27). Surprisingly, more women with advance knowledge (15.8%) had discrepant self reports and PSA results than women without advance knowledge (9.1%); however, the difference was not statistically significant (OR 1.9; 95% CI 0.8 to 4.5).

CONCLUSIONS

Knowing that one's answers to a questionnaire could be verified with a biological marker of semen exposure did not make respondents more likely to report unprotected sex.

Trichomonas vaginalis infection in male sexual partners: implications for diagnosis, treatment, and prevention

BACKGROUND

Trichomonas vaginalis causes a common sexually transmitted infection (STI) in women, yet trichomoniasis in male sexual partners is not well recognized. Nucleic acid amplification tests can increase detection of T. vaginalis in men compared with culture.

METHODS

We conducted a prospective, multicenter study to evaluate T. vaginalis infection among male partners of women with trichomoniasis and factors associated with infection by recruiting patients from 3 public clinics in the United States. Male partners were tested for concordant T. vaginalis infection, defined as a positive urethral culture, urine culture, or urine polymerase chain reaction (PCR) result. A subset of men also provided a semen sample for T. vaginalis culture and PCR. Factors associated with concordant infection were determined from bivariable and multivariable analyses.

RESULTS

We enrolled 540 women with trichomoniasis (diagnosed using wet mount microscopy and/or culture) and 261 (48.4%) of their male partners. T. vaginalis infection was detected in 177 (71.7%) of 256 male partners (95% confidence interval [CI], 66.0%-77.3%), of whom 136 (77.3%) were asymptomatic. A vaginal pH of >4.5 in a woman was independently associated with infection in the male partner (adjusted odds ratio, 2.5; 95% CI, 1.0-6.3). Younger male age (20-29 and 30-39 years) was also found to be an independent risk factor for concordant trichomoniasis.

CONCLUSIONS

The majority of male partners of women with trichomoniasis were infected; however, few factors predicted infection. T. vaginalis causes a highly prevalent STI, necessitating vastly improved partner management, application of sensitive nucleic-acid based testing, and better clinical recognition.

Prostate-specific antigen to ascertain reliability of self-reported coital exposure to semen

OBJECTIVE

The objective of this study was to assess the validity of women's reports of recent unprotected sex by testing for prostate-specific antigen (PSA) in vaginal samples.

STUDY DESIGN

The authors conducted prospective research with 332 female sex workers attending 2 public dispensaries in Madagascar.

RESULTS

Among women who reported no sex or protected sex only within the past 48 hours, 21% and 39%, respectively, tested positive for PSA. Among those testing positive for PSA, no differences in PSA concentrations were found among those reporting no sex, protected sex only, or at least one unprotected act.

CONCLUSIONS

The substantial disagreement between self-reports and measurement of a biologic marker of semen exposure in vaginal specimens substantiates that self-reports of sexual behavior cannot be assumed to be valid measures. Future sexually transmitted infection/HIV and pregnancy prevention studies should confirm the validity of self-reports or use end points that do not rely on self-reported data.

Methods for detection of Trichomonas vaginalis in the male partners of infected women: implications for control of trichomoniasis

Trichomonas vaginalis infection in men is an important cause of nongonococcal urethritis. Effective detection of the parasite in men using culture requires examination of multiple specimens. We compared culture and PCR-enzyme-linked immunosorbent assay in urethral swabs, urine, and semen for T. vaginalis detection in male sexual partners of women with trichomoniasis identified by wet mount and culture. Trichomonads were detected by at least one positive test in 205/280 men (73.2%) who submitted at least one specimen for culture and PCR. Whereas InPouch TV culture detected only 46/205 cases (22.5%), PCR detected 201/205 (98.0%). Urethral swab cultures from men with urethritis were more likely to be positive with shorter incubation than specimens from men without urethritis. T. vaginalis was detected more often in men with wet-mount-positive partners. Even with a sensitive PCR assay, reliable detection of T. vaginalis in male partners required multiple specimens. The majority of male sexual partners in this study were infected, emphasizing the importance of partner evaluation and treatment.

Prevalence of HIV infection among young adults in the United States: results from the Add Health study

OBJECTIVES

We estimated HIV prevalence rates among young adults in the United States.

METHODS

We used survey data from the third wave of the National Longitudinal Study of Adolescent Health, a random sample of nearly 19000 young adults initiated in 1994-1995. Consenting respondents were screened for the presence of antibodies to HIV-1 in oral mucosal transudate specimens. We calculated prevalence rates, accounting for survey design, response rates, and test performance.

RESULTS

Among the 13184 participants, the HIV prevalence rate was 1.0 per 1000 (95% confidence interval [CI] = 0.4, 1.7). Gender-specific prevalence rates were similar, but rates differed markedly between non-Hispanic Blacks (4.9 per 1000; 95% CI=1.8, 8.7) and members of other racial/ethnic groups (0.22 per 1000; 95% CI=0.00, 0.64).

CONCLUSIONS

Racial disparities in HIV in the United States are established early in the life span, and our data suggest that 15% to 30% of all cases of HIV occur among individuals younger than 25 years.

Does a choice of condoms impact sexually transmitted infection incidence? A randomized, controlled trial

OBJECTIVE

The objective of this study was to assess whether providing a choice of condoms would increase condom acceptability, increase self-reported use, and decrease incident sexually transmitted infection.

STUDY

We randomized 414 men presenting with urethral discharge in Jamaica to receive either the "standard" clinic condom or a choice of 4 different types of condoms. Men were treated presumptively at enrollment and followed up at 1, 2, 4, and 6 months.

RESULTS

Participants in the choice group had a strong preference (P <0.01) for the most popular condom available in Jamaica. This preference did not translate into higher condom use (P = 0.16). The 6-month cumulative probability of first incidence of gonorrhea, chlamydia, or trichomoniasis was slightly higher in the choice group (21%; 95% confidence interval [CI], 15-28%) versus the control group (17%; 95% CI, 11-23%); the difference in the survival curves was not significant (P = 0.35).

CONCLUSION

A choice of condoms may increase perceived acceptability but not lead to increased condom use and subsequently lower sexually transmitted infection rates.

The Prevalence of Trichomoniasis in Young Adults in the United States

BACKGROUND AND OBJECTIVES

The prevalence of trichomoniasis in the general population of the United States is unknown. This study provides the first population-based prevalence estimates of trichomoniasis among young adults in the United States.

METHODS

The National Longitudinal Study of Adolescent Health (Add Health) is an ongoing prospective cohort study. In a cross-sectional analysis of Wave III of Add Health (N = 12,449), we determined the prevalence of trichomoniasis using a polymerase chain reaction assay.

RESULTS

The estimated overall prevalence of trichomoniasis in U.S. young adults was 2.3% (95% confidence interval [CI], 1.8-2.7%). The prevalence was slightly higher among women (2.8%; 95% CI, 2.2-3.6%) than men (1.7%; 95% CI, 1.3-2.2%). The prevalence increased with age and varied by region, with the south having the highest prevalence (2.8%; 95% CI, 2.2-3.5%). The prevalence was highest among black women (10.5%; 95% CI, 8.3-13.3%) and lowest among white women (1.1%; 95% CI, 0.8-1.6%). Among men, the prevalence was highest among Native Americans (4.1%; 95% CI, 0.4-29.3%) and blacks (3.3%; 95% CI, 2.2-4.9%), and lowest among white men (1.3%; 95% CI, 0.9-1.8%).

CONCLUSIONS

Trichomoniasis is moderately prevalent among the general U.S. population of young adults and disturbingly high among certain racial/ethnic groups.

Use of an immunochromatographic assay for rapid detection of Trichomonas vaginalis in vaginal specimens

Trichomonas vaginalis infection is estimated to be the most widely prevalent nonviral sexually transmitted infection in the world. Wet-mount microscopy is the most common diagnostic method, although it is less sensitive than culture. The OSOM Trichomonas Rapid Test (Genzyme Diagnostics, Cambridge, Mass.) (referred to here as OSOM) is a new point-of-care diagnostic assay for T. vaginalis that uses an immunochromatographic capillary flow (dipstick) assay and provides results in 10 min. The purpose of this study was to determine the test characteristics of OSOM compared to those of a composite reference standard (CRS) comprised of wet-mount microscopy and T. vaginalis culture. This multicenter cross-sectional study enrolled sexually active women > or =18 years of age who presented with symptoms of vaginitis, exposure to T. vaginalis, or multiple sexual partners. Vaginal-swab specimens were obtained for T. vaginalis culture, wet mount, and rapid testing. The prevalence of T. vaginalis in this sample was 23.4% (105 of 449) by the CRS. The sensitivity and specificity of OSOM vaginal-swab specimens were 83.3 and 98.8%, respectively, while wet mount had a sensitivity and specificity of 71.4 and 100%, respectively, compared to the CRS. OSOM performed significantly better than wet mount (P = 0.004) and detected T. vaginalis in samples that required 48 to 72 h of incubation prior to becoming culture positive. The performance of the rapid test was not affected by the presence of coinfections with chlamydia and gonorrhea. The OSOM Trichomonas Rapid Test is a simple, objective test that can be expected to improve the diagnosis of T. vaginalis, especially where microscopy and culture are unavailable.

Improving the accuracy of syndromic diagnosis of genital ulcer disease in Malawi

OBJECTIVES/GOAL

Most resource-poor settings rely on syndromic criteria to diagnose genital ulcer disease (GUD). However, the etiologic pathogens of GUD vary temporally and geographically, and current criteria may not reflect changes in the prevalence of specific pathogens.

STUDY

In 1999, we estimated the prevalence of Treponema pallidum (Tp), herpes simplex virus (HSV), and Haemophilus ducreyi (Hd) in Malawi. We then used regression coefficients of independent correlates of HSV and Hd to develop weighted diagnostic algorithms, in which weights were beta-coefficients corresponding to each factor.

RESULTS

Overall, a decrease in the proportion of sexually transmitted disease attributable to GUD was noted in 7 years. Thirty-five percent were attributable to HSV, 30% to H. ducreyi, and 4% to T. pallidum. Areas under the receiver operating characteristic curves for weighted and unweighted HSV diagnostic algorithms were 67.6% and 66.5%, respectively. There was no significant difference in the explanatory performance of the weighted and unweighted algorithms.

CONCLUSIONS

Unweighted algorithms can therefore be used to improve diagnostic accuracy of GUD.

Genetic typing of the porin protein of Neisseria gonorrhoeae from clinical noncultured samples for strain characterization and identification of mixed gonococcal infections

Molecular methods that characterize the Neisseria gonorrhoeae porin protein Por are needed to study gonococcal pathogenesis in the natural host and to classify strains from direct clinical samples used with nucleic acid amplification-based tests. We have defined the capabilities of por variable region (VR) typing and determined suitable conditions to apply the method to direct clinical specimens. Nested PCR from spiked urine samples detected 1 to 10 copies of template DNA; freezing spiked whole urine greatly reduced the ability to amplify porB. In a laboratory model of mixed gonococcal infections, the por type of one strain could be determined in the presence of a 100-fold excess of another. por VR typing was used to examine clinical samples from women enrolled in studies conducted in Baltimore, Md., and Madagascar. por type was determined from 100% of paired cervical swab and wick samples from 20 culture-positive women from Baltimore; results for eight individuals (40%) suggested infection with more than one strain. In frozen urine samples from Madagascar, porB was amplified and typed from 60 of 126 samples from ligase chain reaction (LCR)-positive women and 3 samples from LCR-negative women. The por VR types of 13 samples (21%) suggested the presence of more than one gonococcal strain. Five por types, identified in >45% of women with typed samples, were common to both geographic areas. Molecular typing is an important adjunct to nucleic acid amplification-based diagnostics. Methods that utilize direct clinical samples and can identify mixed infections may contribute significantly to studies of host immunity, gonococcal epidemiology, and pathogenesis.

Targeted Screening for Trichomonas vaginalis with Culture Using a Two-Step Method in Women Presenting for STD Evaluation

OBJECTIVES

Trichomonas vaginalis is the most common nonviral sexually transmitted pathogen. Wet mount microscopy performs poorly compared with culture; however, universal screening using culture would be cost-prohibitive.

GOAL

The goal of this study was to develop a predictive model for wet mount-negative women who may benefit from targeted use of culture for T. vaginalis detection.

STUDY

Women presenting for sexually transmitted disease evaluation were prospectively screened for trichomoniasis using wet mount and culture. Multivariate logistic regression was used to identify predictors of culture-proven trichomoniasis among wet mount-negative women.

RESULTS

A total of 2194 women were screened for trichomoniasis; overall, the prevalence of T. vaginalis was 17.5%. Three predictors (any drug use, contact to trichomoniasis, and African-American race) provided the most specific model (100%); any 1 predictor, the most sensitive model (97.8%).

CONCLUSIONS

Given the public health impact of trichomoniasis, we recommend using any 1 of 3 predictors to identify women who would benefit from targeted culture for T. vaginalis.

The Use of Specimens from Various Genitourinary Sites in Men, to DetectTrichomonas vaginalisInfection

Variations in estimates of prevalence of trichomoniasis in men may reflect true differences in the burden of disease but are also affected by the performance of diagnostic methods and the type of specimen tested. In this study, men were evaluated at baseline and at follow-up, to evaluate syndromic management of urethritis and the effects of human immunodeficiency virus and trichomoniasis, in Lilongwe, Malawi. First-void urine specimens and urethral swabs were obtained at enrollment, for Trichomonas vaginalis culture; semen specimens were also obtained at follow-up. The sensitivities of testing methods using urine specimens and urethral swabs were equal; 67% of cases were identified by use of either specimen, and, in 47% of cases, both specimens tested positive. When semen specimens were included, all 3 specimens tested positive in only 19% of cases. Semen was the most sensitive single specimen, and, in 25.6% of cases, only semen specimens tested positive. Thus, prevalence of T. vaginalis infection in men is underestimated if only 1 specimen is tested.

Trichomoniasis: clinical manifestations, diagnosis and management

Trichomonas vaginalis was originally considered a commensal organism until the 1950s when the understanding of its role as a sexually transmitted infection (STI) began to evolve. Trichomoniasis has been associated with vaginitis, cervicitis, urethritis, pelvic inflammatory disease (PID), and adverse birth outcomes. Infection with T vaginalis could have an important role in transmission and acquisition of HIV. T vaginalis is site specific for the genitourinary tract and has been isolated from virtually all genitourinary structures. Asymptomatic disease is common in both men and women, thus screening for disease is important. Various sociodemographic factors have been correlated with presence of T vaginalis, and may be used to predict infection. Diagnosis is usually made from wet mount microscopy and direct visualisation, which are insensitive. DNA amplification techniques perform with good sensitivity, but are not yet approved for diagnostic purposes. In areas where diagnostic methods are limited, management of trichomoniasis is usually as part of a clinical syndrome; vaginal discharge for women and urethral discharge for men. A single dose of metronidazole is effective in the majority of cases. Outside of the United States, other nitroimidazoles may be used and are as effective as metronidazole. Metronidazole resistance is an emerging problem, but its clinical importance is not yet clear. Concomitant treatment of sexual partners is recommended.

Prevalence of chlamydial and gonococcal infections among young adults in the United States

CONTEXT

Chlamydial and gonococcal infections are important causes of pelvic inflammatory disease, ectopic pregnancy, and infertility. Although screening for Chlamydia trachomatis is widely recommended among young adult women, little information is available regarding the prevalence of chlamydial and gonococcal infections in the general young adult population.

OBJECTIVE

To determine the prevalence of chlamydial and gonococcal infections in a nationally representative sample of young adults living in the United States.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional analyses of a prospective cohort study of a nationally representative sample of 14,322 young adults aged 18 to 26 years. In-home interviews were conducted across the United States for Wave III of The National Longitudinal Study of Adolescent Health (Add Health) from April 2, 2001, to May 9, 2002. This study sample represented 66.3% of the original 18,924 participants in Wave I of Add Health. First-void urine specimens using ligase chain reaction assay were available for 12,548 (87.6%) of the Wave III participants.

MAIN OUTCOME MEASURES

Prevalences of chlamydial and gonococcal infections in the general young adult population, and by age, self-reported race/ethnicity, and geographic region of current residence.

RESULTS

Overall prevalence of chlamydial infection was 4.19% (95% confidence interval [CI], 3.48%-4.90%). Women (4.74%; 95% CI, 3.93%-5.71%) were more likely to be infected than men (3.67%; 95% CI, 2.93%-4.58%; prevalence ratio, 1.29; 95% CI, 1.03-1.63). The prevalence of chlamydial infection was highest among black women (13.95%; 95% CI, 11.25%-17.18%) and black men (11.12%; 95% CI, 8.51%-14.42%); lowest prevalences were among Asian men (1.14%; 95% CI, 0.40%-3.21%), white men (1.38%; 95% CI, 0.93%-2.03%), and white women (2.52%; 95% CI, 1.90%-3.34%). Prevalence of chlamydial infection was highest in the south (5.39%; 95% CI, 4.24%-6.83%) and lowest in the northeast (2.39%; 95% CI, 1.56%-3.65%). Overall prevalence of gonorrhea was 0.43% (95% CI, 0.29%-0.63%). Among black men and women, the prevalence was 2.13% (95% CI, 1.46%-3.10%) and among white young adults, 0.10% (95% CI, 0.03%-0.27%). Prevalence of coinfection with both chlamydial and gonococcal infections was 0.030% (95% CI, 0.18%-0.49%).

CONCLUSIONS

The prevalence of chlamydial infection is high among young adults in the United States. Substantial racial/ethnic disparities are present in the prevalence of both chlamydial and gonococcal infections.