Performance of the APTIMA Combo 2 assay for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in female urine and endocervical swab specimens

Development of advanced control material for reverse transcription-mediated bacterial nucleic acid amplification tests

Detection of bacterial RNA by nucleic acid amplification tests (NAATs), such as reverse transcription PCR (RT-PCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP), offers distinct advantages over DNA-based methods. However, such assays also present challenges in ascertaining positive and internal control material that can reliably monitor success over all phases of testing (bacterial lysis, nucleic acid recovery, reverse transcription, amplification, and signal detection): since they are unable to distinguish between amplification of bacterial RNA transcripts and the DNA templates that encode them, using intact organisms as controls can inform cell lysis but not successful detection of RNA. We developed a control strategy for RNA-based bacterial NAATs that allows ready discrimination of RNA from DNA templates using self-splicing bacterial introns, such that those nucleic acids ultimately encode different sequences. We engineered two vectors encoding synthetic transgenes based on this principle, one that is active in the Gram-negative bacterium Escherichia coli and one that functions in both E. coli and the Gram-positive organism Staphylococcus aureus. We subsequently designed RT-LAMP assays that either target RNA and DNA from transgenic organisms or target RNA exclusively and demonstrated the specificity of amplification using purified nucleic acids. Using multiplex fluorescent RT-LAMP of heat-lysed specimens, we showed the practicality of deploying such transgenic organisms as an internal control to ascertain sample integrity and assay performance during clinical diagnostic testing. Our approach has broad utility for RNA-based bacterial NAATs, especially point-of-care assays and other applications where nucleic acids are nonspecifically liberated for testing.

Sexually Transmitted Infections in the Emergency Department

As the United States faces a worsening epidemic of sexually transmitted infections (STIs), emergency departments (EDs) play a critical role in identifying and treating these infections. The growing health inequities in the distribution and disproportionate impact of STIs add to the urgency of providing high-quality sexual health care through the ED. Changes in population health are reflected in the new Centers for Disease Control recommendations on screening, diagnostic testing, and treatment of STIs. This review covers common, as well as and less common or emerging STIs, and discusses the state-of-the-art guidance on testing paradigms, extragenital sampling, and antimicrobial treatment and prevention of STIs.

Validation of a New Duplex Real-Time Polymerase Chain Reaction for Chlamydia trachomatis DNA Detection in Ocular Swab Samples

Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria Chlamydia trachomatis. In developing countries, diagnosis is usually based on clinical evaluation. Serological-based tests are cheaper than molecular-based ones, but the latter are more sensitive and specific. The present study developed a new duplex qPCR which concomitantly detects the C. trachomatis cryptic plasmid and the human 18S rRNA gene, with an LOD95% for C. trachomatis DNA of 13.04 genome equivalents per reaction. The new qPCR was tested using 50 samples from an endemic area and 12 from a non-endemic area that were previously characterized using direct immunofluorescence assay (DFA) and clinical evaluation. Among the 50 endemic samples, 3 were found to be positive by clinical evaluation (6%), 18 were found to be positive by DFA (36%), and 48 were found to be positive by qPCR (96%). Next, the new duplex qPCR was validated using 50 samples previously characterized by qPCR. Validation was carried out on a benchtop instrument (ABI7500) or on a portable point-of-care instrument (Q3-Plus), showing 95% specificity and 100% sensitivity. The ubiquitous presence of C. trachomatis DNA in samples from the endemic region confirms that constant monitoring is of paramount importance for the effective measurement of the elimination of trachoma. The newly developed duplex qPCR presented in this study, along with its validation in a portable qPCR system, constitutes important tools toward achieving this goal.

Disseminated Gonococcal Infection: An Unusual Presentation Resembling a Lupus Flare

We present a misdiagnosed case of disseminated gonococcal infection (DGI) in a patient with pre-existing systemic lupus erythematosus (SLE), complaining of sudden onset polyarthralgia and tenosynovitis. Neisseria gonorrhoeae is a common sexually transmitted disease. It can present in young adults as cervicitis and urethritis but is often asymptomatic. In rare instances, gonorrhea can advance to DGI with symptoms such as tenosynovitis, dermatitis, and polyarthralgias, seen most commonly in the knees, ankles, elbows, fingers, and toes. Once suspected, DGI is definitively diagnosed with blood cultures or synovial fluid analysis. SLE is associated with an increased risk of disseminated infections, including DGI. Therefore, early diagnosis of DGI is critical for successful treatment and recovery. Providers should therefore be conscientious of the overlap in symptoms between DGI and a lupus flare. The purpose of examining this case is to encourage the inclusion of disseminated N. gonorrhoeae infection as a differential diagnosis in SLE patients presenting with acute arthralgias regardless of genitourinary symptoms.

Impact of risk-based sexually transmitted infection screening in the emergency department

OBJECTIVES

Sexually transmitted infections (STIs), including chlamydia, gonorrhea, and human immunodeficiency virus (HIV) pose a significant health burden in adolescents. Many adolescents receiving care in the emergency department (ED) are in need of testing, regardless of their chief complaint. Our objective was to determine whether an electronic, risk-based STI screening program in our ED was associated with an increase in STI testing among at-risk adolescents.

METHODS

We conducted a retrospective cohort analysis of patient outcomes in our pediatric ED after integrating an Audio-enhanced Computer-Assisted Self-Interview (ACASI) as standard of care. It obtained a focused sexual history and generated STI testing recommendations. Patient answers and testing recommendations were integrated in real-time into the electronic health record. Patients who tested positive received treatment according to our standard-of-care practices. All patients 15-21 years of age were asked to complete this on an opt-out basis, regardless of the reason for their ED visit. Exclusions included those unable to independently use a tablet, severe illness, sexual assault, or non-English speaking. Our primary outcome was to describe STI-testing recommendations and test results among ACASI participants. We also compared STI testing between ACASI participants and those who were eligible but did not use it.

RESULTS

In the first 13 months, 28.9% (1788/6194) of eligible adolescents completed the ACASI and 44.2% (321/790) accepted recommended STI testing. The mean age of participants was 16.6 ± 1.3 years, with 65.4% (1169) being female. Gonorrhea/chlamydia testing was significantly higher among participants vs. non-participants (20.1% [359/1788] vs 4.8% [212/4406]; p < 0.0001). The proportion of positive STI tests was similar between the two groups: 24.8% (89/359) vs. 24.5% (52/212; p = 0.94) were positive for chlamydia and/or gonorrhea, while 0.6% (2/354) participants vs. 0% non-participants (p > 0.99) were positive for HIV. Among participants whose chief complaints were unlikely to be related to STIs but accepted recommended testing, 20.9% (37/177) were positive for gonorrhea or chlamydia.

CONCLUSIONS

Our program facilitated STI testing in the ED and identified many adolescents with STIs, even when their ED complaint was for unrelated reasons. More rigorous implementation is needed to determine the impact of deployment of ACASI to all eligible adolescents and addressing barriers to accepting STI testing recommendations.

Impact of Rapid Testing for Gonorrhea and Chlamydia in an Urban Pediatric Emergency Department

PURPOSE

To determine the impact of rapid testing for gonorrhea (NG) and chlamydia (CT) on accuracy of treatment in adolescents in the pediatric emergency department (ED).

METHODS

Retrospective study of adolescents tested for NG and CT in the pediatric ED before and after implementation of rapid testing. Treatment during initial visit, availability of test results prior to discharge, and number of follow-up phone calls made with test results were compared. Appropriate treatment was defined per Centers for Disease Control and Prevention 2015 guidelines as monotherapy for CT and dual therapy for NG. Descriptive statistics were used to compare groups.

RESULTS

Rapid testing improved treatment accuracy with 522 (79.3%) patients treated appropriately in the rapid testing group compared to 478 (64.7%) patients in the batched testing group (p < .001). Inaccurate treatment was more common in the batch testing group among those who tested negative (p < .001). Among those who tested positive for NG and/or CT, phone calls were made to 54 (47.8%) patients in the rapid testing group and 129 (84.3%) patients in the batched testing group to discuss positive test results (p < .001).

CONCLUSION

Compared to batched testing, rapid testing is associated with improved accuracy of treatment of NG and CT in the pediatric ED setting. Additionally, rapid testing is associated with decreased number of phone calls to discuss positive test results.

Association between Chlamydia trachomatis, Neisseria gonorrhea, Mycoplasma genitalium, and Trichomonas vaginalis and Secondary Infertility in Cameroon: A case-control study

Objective

Data on the prevalence and etiology of infertility in Africa are limited. Secondary infertility is particularly common, defined as the inability of a woman to conceive for at least one year following a full-term pregnancy. We describe a prospective study conducted in Cameroon designed to test the hypothesis of an association between common treatable sexually transmitted infections (STI): Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), and Trichomonas vaginalis (TV) and secondary infertility in women.

Methods

In this case-control study, we enrolled women in Fako Division, Cameroon between November 2017 and December 2018 with secondary infertility (cases) or current pregnancy (controls). We conducted a baseline survey to collect sociodemographic, and sexual and medical history information. Nucleic acid amplification testing using Aptima (Hologic, San Diego, CA, US) was performed on endocervical swabs for CT, NG, MG, and TV. Multivariable logistic regression was used to assess the relationship between active STI and secondary infertility.

Results

A total of 416 women were enrolled: 151 cases and 265 controls. Compared to controls, cases were older (median age 32 vs 27 years) and had more lifetime sexual partners (median 4 vs 3) (p<0.001). Cases were more likely to report dyspareunia, abnormal menses, prior miscarriage, and ectopic pregnancy (all p<0.05). STI positivity was not significantly different among cases and controls (2.7% vs 5.4% for CT, 1.3% vs 2.9% for NG, 6.0% vs 7.0% for MG, respectively), with the exception of TV which was more common in pregnant controls (0.7% vs 5%; p = 0.02).

Conclusion

Study findings did not support an association between active STI and secondary infertility in Cameroon. Given high rates of pre-existing tubal damage, routine STI screening and treatment in younger women may be more impactful than costly STI testing during infertility assessments.

Generalized additive regression for group testing data

In screening applications involving low-prevalence diseases, pooling specimens (e.g., urine, blood, swabs, etc.) through group testing can be far more cost effective than testing specimens individually. Estimation is a common goal in such applications and typically involves modeling the probability of disease as a function of available covariates. In recent years, several authors have developed regression methods to accommodate the complex structure of group testing data but often under the assumption that covariate effects are linear. Although linearity is a reasonable assumption in some applications, it can lead to model misspecification and biased inference in others. To offer a more flexible framework, we propose a Bayesian generalized additive regression approach to model the individual-level probability of disease with potentially misclassified group testing data. Our approach can be used to analyze data arising from any group testing protocol with the goal of estimating multiple unknown smooth functions of covariates, standard linear effects for other covariates, and assay classification accuracy probabilities. We illustrate the methods in this article using group testing data on chlamydia infection in Iowa.

Diagnosis of Chlamydia trachomatis genital infections in the era of genomic medicine

PURPOSE

Chlamydial genital infections constitute significant sexually transmitted infections worldwide. The often asymptomatic status of C. trachomatis (CT) infections leads to an increased burden on human reproductive health, especially in middle- and low-income settings. Early detection and management of these infections could play a decisive role in controlling this public health burden. The objective of this review is to provide an insight into the evolution of diagnostic methods for CT infections through the development of new molecular technologies, emphasizing on -omics' technologies and their significance as diagnostic tools both for effective patient management and control of disease transmission.

METHODS

Narrative review of the diagnostic methodologies of CT infections and the impact of the introduction of -omics' technologies on their diagnosis by review of the literature.

RESULTS

Various methodologies are discussed with respect to working principles, required specifications, advantages, and disadvantages. Implementing the most accurate methods in diagnosis is highlighted as the cornerstone in managing CT infections.

CONCLUSION

Diagnostics based on -omics' technologies are considered to be the most pertinent modalities in CT testing when compared to other available methods. There is a need to modify these effective and accurate diagnostic tools in order to render them more available and feasible in all settings, especially aiming on turning them to rapid point-of-care tests for effective patient management and disease control.

Using Innovation to Address Adolescent and Young Adult Health Disparities in Pelvic Inflammatory Disease: Design of the Technology Enhanced Community Health Precision Nursing (TECH-PN) Trial

New approaches to pelvic inflammatory disease (PID) care among adolescents and young adults (AYAs) that optimize self-care and personalize treatment are warranted to address age and racial-ethnic PID-related health disparities. Here we describe the 13-month preliminary feasibility and acceptability outcomes of recruitment, retention, and intervention delivery for Technology Enhanced Community Health Precision Nursing (TECH-PN) randomized controlled trial. Urban AYAs 13-25 years assigned female sex at birth with acute mild-moderate PID provided baseline and follow-up interview data and vaginal specimens for sexually transmitted infection (STI), cytokine, and microbiota assessment. All participants received medications and text-messaging support. Participants were block randomized to either control or intervention. Control participants received 1 community nursing visit with self-management for interim care per national guidelines. Intervention participants received unlimited precision care services driven by interim STI and macrolide resistance testing results by an advanced practice provider. In the first 13 months, 75.2% patients were eligible, and 76.1% of eligible patients enrolled. Of the participants, 94% completed the intervention and 96%, 91%, and 89%, respectively, completed their 14-, 30-, and 90-day visits. Baseline laboratory results revealed infection rates that were highest for Mycoplasma genitalium (45%) followed by Chlamydia trachomatis (31%). Preliminary enrollment, STI, intervention delivery, and retention data demonstrate the feasibility and acceptability of the TECH-PN intervention and support rationale for precision care for PID among urban AYAs. ClinicalTrials.gov Identifier. NCT03828994.

The clinical indications for testing women for Mycoplasma genitalium

BACKGROUND

While the contribution of Mycoplasma genitalium (MG) to symptoms in men is well described, less is known about its association with common genital symptoms in women. We aimed to determine the prevalence of MG and macrolide resistance, and its association with common genital symptoms in women attending a sexual health service, to inform indications for testing and clinical practice.

METHODS

We undertook a cross-sectional study of symptomatic and asymptomatic women attending Melbourne Sexual Health Centre (MSHC), between April 2017 and April 2019. Women were tested for MG and macrolide resistance, Chlamydia trachomatis (CT), Neisseria gonorrhoeae, Trichomonas vaginalis, bacterial vaginosis and vulvovaginal candidiasis. Women completed a questionnaire on symptoms, and symptomatic women underwent examination. The prevalence of MG (and macrolide resistance) and other genital infections was calculated with 95% CIs, and associations between these outcomes and specific genital symptoms were examined using logistic regression.

RESULTS

Of 1318 women, 83 (6%, 95% CI: 5% to 8%) had MG, of which 39 (48%, 95% CI: 36% to 59%) had macrolide-resistant MG; 103 (8%, 95% CI: 6% to 9%) women had CT. MG prevalence was similar in asymptomatic (10 of 195; 5%) and symptomatic (73 of 1108; 7%) women, p=0.506. MG was associated with mucopurulent cervicitis on examination (adjusted OR=4.38, 95% CI: 1.69 to 11.33, p=0.002), but was not associated with other specific genital symptoms or signs.

CONCLUSIONS

MG was as common as CT among women attending MSHC. MG was not associated with genital symptoms, but like CT, was significantly associated with cervicitis. These data provide evidence that routine testing for MG in women with common genital symptoms is not indicated. The presence of macrolide resistance in 48% of women supports use of resistance-guided therapy.

Array testing for multiplex assays

Group testing involves pooling individual specimens (e.g., blood, urine, swabs, etc.) and testing the pools for the presence of disease. When the proportion of diseased individuals is small, group testing can greatly reduce the number of tests needed to screen a population. Statistical research in group testing has traditionally focused on applications for a single disease. However, blood service organizations and large-scale disease surveillance programs are increasingly moving towards the use of multiplex assays, which measure multiple disease biomarkers at once. Tebbs and others (2013, Two-stage hierarchical group testing for multiple infections with application to the Infertility Prevention Project. Biometrics69, 1064-1073) and Hou and others (2017, Hierarchical group testing for multiple infections. Biometrics73, 656-665) were the first to examine hierarchical group testing case identification procedures for multiple diseases. In this article, we propose new non-hierarchical procedures which utilize two-dimensional arrays. We derive closed-form expressions for the expected number of tests per individual and classification accuracy probabilities and show that array testing can be more efficient than hierarchical procedures when screening individuals for multiple diseases at once. We illustrate the potential of using array testing in the detection of chlamydia and gonorrhea for a statewide screening program in Iowa. Finally, we describe an R/Shiny application that will help practitioners identify the best multiple-disease case identification algorithm.

Prevalence of Neisseria gonorrhoeae in the west of Iran

Neisseria gonorrhoeae (N. gonorrhoeae) is one of the causing factors of sexually transmitted diseases (STDs). This bacterium infects the epithelial cells of the cervix of women and urethra of men. However, the symptoms in the lower genitalia are found only in a small percentage of people. The aim of this study was comparing the frequency of N. gonorrhoeae genital infection among two groups of pregnant women (spontaneous abortion and normal pregnancy).This cross-sectional study was performed in the west of Iran. This study was performed on 417 women who consisted of 109 spontaneous abortions, 109 normal deliveries, 100 fertilities and 99 infertile women. Specific primers were used and DNA was extracted by endocervical swabs; then a Polymerase chain reaction (PCR) test was done for detection of N. gonorrhoeae. Data analysis was carried out using Chi-Square Test and t-Test. In all of the above-said steps, a level of 5% was considered significant.The average age in women with normal delivery (27.8±4.87) in women with spontaneous abortion (29.6±5.9) in fertile women (32.1±5.1) and in infertile women were (29.1±6.3). The total frequency of N. gonorrhea infection was 0 (0%). Prevalence of N. gonorrhoeae infection was zero; also it was not associated with spontaneous abortion and infertility.

Oropharyngeal gonorrhoea infections among heterosexual women and heterosexual men with urogenital gonorrhoea attending a sexual health clinic in Melbourne, Australia

OBJECTIVES

There is limited evidence about the transmission and prevalence of oropharyngeal gonorrhoea in heterosexuals. From August 2017, Melbourne Sexual Health Centre (MSHC) began testing for oropharyngeal gonorrhoea among heterosexuals with untreated urogenital gonorrhoea. This study aims to determine the positivity of oropharyngeal gonorrhoea among heterosexuals diagnosed with urogenital gonorrhoea at MSHC between August 2017 and May 2020.

METHODS

We included individuals who had oropharyngeal gonorrhoea testing within 30 days of initial testing. We reported the number and proportion of oropharyngeal gonorrhoea positivity, stratified by gender and contact of gonorrhoea. The χ² test was performed to compare the oropharyngeal gonorrhoea positivity between groups.

RESULTS

Of 617 individuals with untreated urogenital gonorrhoea, 424 (68.7%) were tested for oropharyngeal gonorrhoea. Oropharyngeal gonorrhoea positivity was 38.9% (95%CI 34.2-43.7%, 165/424), and was higher in women than in men (115/252, 45.6% versus 50/172, 29.1%, p = 0.001). Furthermore, oropharyngeal gonorrhoea positivity was higher among individuals who were contacts of gonorrhoea cases compared to those who were not (29/44, 65.9% versus 136/380, 35.8%, p < 0.001). There was also no significant difference between women who were sex workers and those who were not (30/78, 38.5% versus 85/174, 48.9%, p = 0.126).

CONCLUSIONS

Our data suggest that oropharyngeal gonorrhoea infection is common among heterosexual women and heterosexual men with untreated urogenital gonorrhoea. Testing heterosexual women and heterosexual men for oropharyngeal gonorrhoea will identify a significant proportion with unrecognized oropharyngeal infections whose recommended treatment is different in some countries.

Performance of a single-use, rapid, point-of-care PCR device for the detection of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis: a cross-sectional study

BACKGROUND

Timely detection and treatment are important for the control of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. The objective of this study was to measure the performance of the Visby Medical Sexual Health Test, a single-use, point-of-care PCR device.

METHODS

Women aged 14 years and older who presented consecutively to ten clinical sites across seven US states were enrolled for a cross-sectional, single-visit study. Patients who consented to participate, and who had not used any exclusionary products in the genital area in the previous 48 h, provided self-collected vaginal swabs for testing with the investigational device. Untrained operators received the specimens and ran the device using the guide provided. Specimens had to be run within 2 h of collection to be considered valid. For comparison, patient-infected status was derived by testing clinician-collected vaginal specimens with the Hologic Aptima Combo 2 Assay and Aptima Trichomonas vaginalis Assay, as well as the BD ProbeTec CT/GC Qx Amplified DNA Assay and BD ProbeTec Trichomonas vaginalis Qx Assay. If the results of those assays did not match, the BD MAX CT/GC/TV was used as a tiebreaker. The primary outcomes were the sensitivity and specificity of the investigational device for the detection of C trachomatis, N gonorrhoeae, and T vaginalis compared with patient-infected status.

FINDINGS

Between Feb 25, 2019, and Jan 6, 2020, 1585 participants aged between 14 years and 80 years (mean 34·8 [SD 14·2]) were enrolled. 1555 participants had tests run with the investigational device, of whom 1532 (98·5%) had a valid result on either the first or repeat test. Among the patients with evaluable results (including a determinate patient-infected status), the device had a sensitivity of 97·6% (95% CI 93·2-99·2) and specificity of 98·3% (97·5-98·9) for C trachomatis (n=1457), sensitivity of 97·4% (86·5-99·5) and specificity of 99·4% (98·9-99·7) for N gonorrhoeae (n=1468), and sensitivity of 99·2% (95·5-99·9) and specificity of 96·9% (95·8-97·7) for T vaginalis (n=1449).

INTERPRETATION

This innovative, rapid, easy-to-use, single-use, point-of-care device to detect C trachomatis, N gonorrhoeae, and T vaginalis infections showed excellent sensitivity and specificity, and could represent an important advance in the development of rapid diagnostics for sexually transmitted infections and other infectious diseases.

FUNDING

Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases.

Performance of 4 Molecular Assays for Detection of Chlamydia and Gonorrhea in a Sample of Human Immunodeficiency Virus-Positive Men Who Have Sex With Men

BACKGROUND

Nucleic acid amplification testing (NAAT) is the preferred method to detect Chlamydia trachomatis and Neisseria gonorrhoeae, but information regarding performance of currently available assays is needed. This study evaluated the performance of the Aptima Combo 2, GeneXpert, cobas4800, and ProbeTec Q (CTQ/GCQ) to detect chlamydia and gonorrhea in pharyngeal, rectal, and urine specimen.

METHODS

Adult male patients seen at an urban human immunodeficiency virus clinic in Birmingham, Alabama who reported sex with men (men who have sex with men) and no antibiotic use in the past 30 days were enrolled between November 2014 and December 2016. Following a baseline survey, rectal and initial void urine specimens were self-collected. A composite infection standard was used, where 1 assay was compared with 3 others to determine sensitivity and specificity estimates for rectal and urine samples. Two pharyngeal samples were clinician-collected for chlamydia and gonorrhea testing and both had to be positive to be considered a true positive.

RESULTS

Among the 181 men enrolled into the study, 15.5% and 7.2% had at least 1 positive chlamydia and gonorrhea result at any site, respectively. Among all 4 assays, chlamydia sensitivity rates ranged from 82% to 96% among rectal samples. Rectal gonorrhea sensitivity estimates ranged from 67% to 99%. The GCQ assay was less sensitive in detecting rectal gonorrhea compared with the other assays (P = 0.02).

CONCLUSIONS

More than 80% of chlamydia and gonorrhea infections would have been missed with urine-only screening, highlighting the importance in using NAATs to detect chlamydia and gonorrhea infections among men who have sex with men.

Comparison between Aptima® assays (Hologic) and the CoBAS® 6800 system (Roche) for the diagnosis of sexually transmitted infections caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium

Nowadays, it is of utmost importance to use fully validated assays for molecular-based diagnosis. In the field of sexually transmitted disease (STD), Roche and Hologic provide assays for diagnosing Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), and Trichomonas vaginalis (TV). A total of 212 clinical samples were tested. Aptima® Combo 2 (detecting CT and NG), Aptima® M. genitalium and the Aptima® T. vaginalis on the Panther® system were compared to CoBAS® CT/NG and CoBAS® TV/MG running on the CoBAS® 6800 system. To solve the discrepancies, Allplex™ STI Essential assay (Seegene®) and/or Sanger DNA sequencing were used. The diagnostic performance was calculated by mean of the sensitivity and specificity parameters. Aptima® (sensitivity: 98.90%, specificity: 100%), CoBAS® (sensitivity 100%, specificity: 96.67%). The CoBAS® combo (CT/NG) failed detecting NG from an anal/rectum specimen, which is not included into the validated specimens of the assay. Aptima® combo 2 produced two false positives (CT and NG), not detected by the third tests. All the assays showed an optimal diagnostic capacity, meeting the requirements for IVD DNA-based assays. All products work optimally on automatic platforms, minimizing time and risk of contamination during handling.

Chlamydia trachomatis Infection, when Treated during Pregnancy, Is Not Associated with Preterm Birth in an Urban Safety-Net Hospital

Preterm birth is a major public health problem, occurring in more than half a million births per year in the United States. A number of maternal conditions have been recognized as risk factors for preterm birth, but for the majority of cases, the etiology is not completely understood. Chlamydia trachomatis is one of the most prevalent sexually transmitted infections in the world. However, its role in adverse pregnancy outcome in women is still debated. In order to determine if genitourinary tract infection with C. trachomatis during pregnancy was associated with preterm birth, we conducted a case-control study on women who delivered at Boston Medical Center, an urban "safety-net" hospital that serves a socioeconomically disadvantaged and racially diverse population. Women with known risk factors for preterm birth or immune suppression were excluded. Variables collected on enrolled subjects included demographics; diagnosis of C. trachomatis during or prior to pregnancy; tobacco, alcohol, and illicit substance use; gestational age; and birthweight and gender of the newborn. We also collected urine for chlamydia testing at the time of delivery and placental biopsies for nucleic acid amplification and histological studies. A total of 305 subjects were enrolled: 100 who delivered preterm and 205 who delivered full term. Among those subjects, we identified 19 cases of pregnancy-associated C. trachomatis infection: 6/100 preterm and 13/205 full term, a difference which was not statistically significant. Only two cases of untreated chlamydia infection were identified postpartum, and both occurred in women who delivered at term. We conclude that genitourinary tract infection with C. trachomatis during pregnancy, when appropriately treated, is not associated with preterm birth.

Detection of chlamydia trachomatis infection among the pregnant women attending a tertiary care hospital in Kerala - South India by polymerase chain reaction

Background

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome.

Aims and Objectives

This study was conducted to assess Chlamydial infection during pregnancy by PCR.

Materials and Methods

Study group consists of patients who are attending the antenatal clinics. Endocervical swabs were collected from 300 patients.

Results

Off the 300 samples tested, 29 were positive as per PCR which used CT F : 5' CGT GTC GGC AAT CCT GCT GAT 3' and CT R : 5' GTC GAT AAC ATA GTC ACG ATA GTC 3'as the primers.

Conclusion

This suggests there is a prevalence of Chlamydia trachomatis in our population which is 10%. Hence, it should be noted as a significant public health problem especially among sexually active young women of child bearing age. Timely detection and prompt treatment of Chlamydial infection during pregnancy can eliminate its adverse outcomes.

Pooling Pharyngeal, Anorectal, and Urogenital Samples for Screening Asymptomatic Men Who Have Sex with Men for Chlamydia trachomatis and Neisseria gonorrhoeae

Screening for Chlamydia trachomatis and Neisseria gonorrhoeae at the pharyngeal, urogenital, and anorectal sites is recommended for men who have sex with men (MSM). Combining the three individual-site samples into a single pooled sample could result in significant cost savings, provided there is no significant sensitivity reduction. The aim of this study was to examine the sensitivity of pooled samples for detecting chlamydia and gonorrhea in asymptomatic MSM using a nucleic acid amplification test. Asymptomatic MSM who tested positive for chlamydia or gonorrhoea were invited to participate. Paired samples were obtained from participants prior to administration of treatment. To form the pooled sample, the anorectal swab was agitated in the urine specimen transport tube and then discarded. The pharyngeal swab and 2 ml of urine sample were then added to the tube. The difference in sensitivity between testing of pooled samples and individual-site testing was calculated against an expanded gold standard, where an individual is considered positive if either pooled-sample or individual-site testing returns a positive result. All samples were tested using the Aptima Combo 2 assay. A total of 162 MSM were enrolled in the study. Sensitivities of pooled-sample testing were 86% (94/109; 95% confidence interval [CI], 79 to 92%]) for chlamydia and 91% (73/80; 95% CI, 83 to 96%) for gonorrhea. The sensitivity reduction was significant for chlamydia (P = 0.02) but not for gonorrhea (P = 0.34). Pooling caused 22 infections (15 chlamydia and 7 gonorrhoea) to be missed, and the majority were single-site infections (19/22). Pooling urogenital and extragenital samples from asymptomatic MSM reduced the sensitivity of detection by approximately 10% for chlamydia but not for gonorrhea.

Using Provider Incentives and an Opt-Out Strategy in a Successful Quality Initiative to Increase Chlamydia Screening

BACKGROUND

Chlamydia trachomatis (CT) is a highly prevalent sexually transmitted infection in adolescents that can lead to serious complications. San Francisco has one of the highest rates of CT infections in the United States. At baseline, screening rates at the Children's Health Center were significantly below national and network levels. This project aimed to increase screening rates for female patients age 16-24 from 29.2% to 44% in an 18-month period.

METHODS

The organization engaged providers, residents, and nursing staff to understand the root causes and choose the screening approach. The following strategies were used to implement this approach in primary and urgent care: (1) universal urine collection, (2) provider and staff education, and (3) adoption of faculty Maintenance of Certification (MOC) credit and resident physician financial incentives.

RESULTS

The annual screening rate for CT in primary care female patients 16-24 years old increased from 29.2% to 61.5% in 18 months, and improved to 71.2% one year after the project. Screening rates for female patients over age 15 seen in the colocated urgent care also increased significantly. The research team found no instances of false positive results and had 4 positive results in high-risk patients who initially reported abstinence.

CONCLUSIONS

The intervention design and engagement of stakeholders with incentives was associated with significant and sustainable improvements in the CT screening rate for female adolescent primary care patients. This work shows how universal opt-out screening can be a sustainable and effective method to address common barriers to increasing screening for CT in adolescents.

Diagnosis of some genital-tract infections: part 2. Molecular tests and the new challenges

Promptly and accurately diagnosing genital-tract infections is key to instituting appropriate treatment and control of sexually transmitted infections (STIs). Ano-genital tract testing for STIs in the last two decades has not entirely moved away from insensitive methods but it is now at least dominated by highly sensitive molecular methods. These tests can be ordered through the internet for use at home, with self-taken specimens then returned, usually by post, to a clinic or laboratory for testing. The increasing ease of access of the public to this situation, together with increasing on-line health-seeking behaviour, has resulted in a gap between commercial and NHS management pathways for STIs. Crucially, patients who order multiplex test kits on-line for use at home, and other non-specialists, may not realize that it is worthwhile testing only for Neisseria gonorrhoeae, Chlamydia trachomatis, and possibly Trichomonas vaginalis, and Mycoplasma genitalium if the person is symptomatic or their current partner is infected. The detection and recommended treatment of micro-organisms which to some extent are part of the genital-tract microbiome, such as Mycoplasma hominis, Ureaplasma spp. or Gardnerella vaginalis, which do not cause symptoms in the majority of those infected, cannot be recommended. We argue that a shift from specialist-led to patient- and non-specialist-led STI management, in the presence of a clinical leadership vacuum, has increased the risk of inappropriate and unnecessary treatment which will drive macrolide, tetracycline and metronidazole antimicrobial resistance. However, in the past 5–6 years several groups have been able to show the value of on-line testing as a consequence of targeting the most important micro-organisms and using molecular tests to allow rapid and appropriately informed treatment. This should herald a brighter future, although there is still a need for leadership to expertly guide commercial and NHS sectors alike. In turn, this requires dedicated genito-urinary medicine commissioning to be maintained at a time when it appears to be most under threat.

Characterization of antimicrobial resistance genes from Neisseria gonorrhoeae positive remnant Aptima urine specimens

Aim: To ascertain the antimicrobial resistance and strain types (STs) of Neisseria gonorrhoeae from 50 remnant Aptima urine specimens using molecular methods. Methods: Mutations predictive of resistance to six antibiotics were identified in eight genes. STs were determined using NG-MAST and NG-STAR. Results: All eight antimicrobial resistance genes could be characterized in 36 specimens. A total of 17 specimens were predicted to be susceptible to all antibiotics, including ceftriaxone. Decreased susceptibility to cefixime and ciprofloxacin resistance was predicted in 11 specimens (PBP2 type 34.001). Overall, 38/50 specimens were predicted to be ciprofloxacin susceptible; three were azithromycin resistant. Nineteen NG-MAST and 21 NG-STAR STs were noted. Conclusion: Molecular analysis of remnant Aptima specimens enabled the prediction of emerging gonococcal cefixime and azithromycin resistance which would otherwise have been undetected.

Rapid and accurate diagnosis of Chlamydia trachomatis in the urogenital tract by a dual-gene multiplex qPCR method

Introduction. Chlamydia trachomatis (C. trachomatis, CT) is an obligatory intracellular bacterium that causes urogenital tract infections and leads to severe reproductive consequences. Therefore, a rapid and accurate detection method with high sensitivity and specificity is an urgent requirement for the routine diagnosis of C. trachomatis infections.Aim. In this study, we aimed to develop a multiplex quantitative real-time PCR (qPCR) assay based on two target regions for accurate detection of C. trachomatis in urogenital tract infections.Methodology. Primers and probes based on the conserved regions of the cryptic plasmid and 23S rRNA gene were designed. Then, two qPCR assays were established to screen for the optimal probe and primers for each of the two target regions. Subsequently, the multiplex qPCR method was developed and optimized. For the diagnostic efficiency evaluation, 1284 urogenital specimens were tested by the newly developed multiplex qPCR method, an immunological assay and a singleplex qPCR assay widely used in hospitals.Results. The multiplex qPCR method could amplify both target regions in the range of 1.0×10²-1.0×10⁸ copies ml^-1 with a strong linear relationship, and lower limits of detection (LODs) for both targets reached 2 copies PCR^-1. For the multiplex qPCR method, the diagnostic sensitivity and specificity was 100.0 % (134/134) and 99.3 % (1142/1150), respectively. For the singleplex qPCR assay, the diagnostic sensitivity and specificity was 88.8 % (119/134) and 100.0 % (1150/1150), respectively. For the immunological assay, the diagnostic sensitivity and specificity was 47.0 % (63/134) and 100.0 % (1150/1150), respectively.Conclusion. In this study, a multiplex qPCR assay with high sensitivity and specificity for rapid (≤2.0 h) and accurate diagnosis of C. trachomatis was developed. The qPCR assay has the potential to be used as a routine diagnostic method in clinical microbiology laboratories.

Chlamydia-Induced Reactive Arthritis: Disappearing Entity or Lack of Research?

PURPOSE OF REVIEW

Recent studies regarding the frequency of Chlamydia-induced reactive arthritis (ReA) are reviewed, with a focus on the question of whether the entity is in fact disappearing or whether it is simply being underdiagnosed/underreported. Epidemiological reports indicate diversity in the frequency of Chlamydia-associated ReA in various parts of the world, with evidence of declining incidence in some regions.

RECENT FINDINGS

The hypothesis that early effective treatment with antibiotics prevents the manifestation of Chlamydia-associated ReA requires further investigation. For clinicians, it is important to remember that ReA secondary to Lymphogranuloma venereum (LGV) serovars L1-L3 of C. trachomatis is probably underestimated due to a limited awareness of this condition, the re-emergence in Western countries of LGV overall, and the present increasingly rare classical inguinal presentation.

Simultaneous detection of eleven sexually transmitted agents using multiplexed PCR coupled with MALDI-TOF analysis

Purpose

Sexually transmitted infections (STIs), representing a major global health problem, are caused by different microbes, including bacteria, viruses, and protozoa. Unfortunately, infections of different sexually transmitted pathogens often present similar clinical symptoms, so it is almost impossible to distinguish them clinically. Therefore, the aim of the current study was to develop a sensitive, multitarget, and high-throughput method that can detect various agents responsible for STIs.

Methods

We developed and tested a 23-plex PCR coupled with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) assay (sexually transmitted infection-mass spectrometry, STI-MS) that simultaneously targets 11 different agents, including 8 most common clinical pathogens related to STIs (HSV-1, HSV-2, Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, Trichomonas vaginalis, Mycoplasma genitalium, and Haemophilus ducreyi) and 3 controversial microorganisms as pathogens (Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum).

Results

The results showed that the STI-MS approach can accurately detect the expected agents, without cross-reaction with other organisms. The limit of detection of each STI-MS assay was ranged from 1.739 to 10.009 copies/reaction, using probit analyses. The verification rate for each target organism of the STI-MS ranged from a minimum of 89.3% to a maximum of 100%, using conventional assays and ultrasensitive digital PCR to confirm the STI-MS-positive results. To further evaluate the clinical performance of this assay, 241 clinical specimens (124 urethral/cervical swabs and 117 urine) were tested in parallel using the STI-MS assay and monoplex real-time PCR for each agent. The overall validation parameters of STI-MS were extremely high including sensitivity (from 85.7% to 100%), specificity (from 92.3% to 100%), PPV (from 50% to 100%), and NPV (from 99.1% to 100%) for each target.

Conclusion

STI-MS is a useful high-throughput screening tool for detecting mixed infections of STIs and has great potential for application in large-scale epidemiological programs for specific microorganisms of STI.

Meta-analysis of the Cepheid Xpert® CT/NG assay for extragenital detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections

Background Most studies evaluating extragenital testing performance for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) detection by the Xpert® CT/NG show high per cent agreement with comparison assays; however, the precision around positive per cent agreement is low and thus the values that have been reported are not highly informative. Therefore, a systematic review was conducted and data from five studies were combined to better assess positive per cent agreement.

METHODS

The literature indexed on PubMed.gov was searched. Included studies were those that were an evaluation of the Xpert CT/NG assay with rectal and/or pharyngeal specimen types compared with another nucleic acid amplification test (NAAT), the Aptima transcription mediated amplification assay. A full Bayesian method was used for bivariate fixed-effect meta-analysis of positive and negative per cent agreement and pooled estimates (and 95% confidence intervals (CI)) were presented for each.

RESULTS

The pooled positive and negative per cent agreement for detection of CT in rectal specimens was 89.72% (95% CI: 84.97%, 93.64%) and 99.23% (95% CI: 98.74%, 99.60%), and in pharyngeal specimens, they were 89.96% (95% CI: 66.38%, 99.72%) and 99.62% (95% CI: 98.95%, 99.95%) respectively. For NG detection in rectal specimens, the pooled positive and negative per cent agreement was 92.75% (95% CI: 87.91%, 96.46%) and 99.75% (95% CI: 99.46%, 99.93%), and in pharyngeal specimens, they were 92.51% (95% CI: 85.84%, 97.18%) and 98.56% (95% CI: 97.69%, 99.23%) respectively.

CONCLUSIONS

It was found that the Xpert CT/NG assay performed similarly to the Aptima transcription mediated amplification assay for the detection of CT and NG in extragenital specimens. The Xpert assay has the benefit of providing faster results at the point-of-care, thus reducing the turnaround time for results, potentially enabling same-day treatment.

Caution Is Required When Using Non-Food and Drug Administration-Cleared Assays to Diagnose Sexually Transmitted Infections in Children

Nucleic acid amplification testing is the gold-standard for Chlamydia trachomatis and Neisseria gonorrhoeae testing in adults. We present 3 pediatric cases in which testing resulted in probable false-positive results. Clinicians should avoid tests without clearance from a regulatory agency and should maintain consistent communication with laboratories.

Comparison of an in-house real-time duplex PCR assay with commercial HOLOGIC® APTIMA assays for the detection of Neisseria gonorrhoeae and Chlamydia trachomatis in urine and extra-genital specimens

BACKGROUND

Extra-genital Neisseria gonorrhoeae and Chlamydia trachomatis infections are mostly asymptomatic, and important reservoir sites of infection as they often go undetected and may be more difficult to eradicate with recommended therapeutic regimens. Commercial nucleic acid amplification tests (NAATs) have not received regulatory approval for the detection of N. gonorrhoeae and C. trachomatis in extra-genital specimens. The HOLOGIC® APTIMA Combo2 assay for N. gonorrhoeae and C. trachomatis has performed well in evaluations using extra-genital specimens.

METHODS

We assessed the performance of an in-house real-time duplex PCR assay for the detection of N. gonorrhoeae and C. trachomatis in urine and extra-genital specimens using the HOLOGIC® APTIMA assays as gold standard comparators. Urine, oropharyngeal and ano-rectal specimens were collected from each of 200 men-who-have-sex-with-men (MSM) between December 2011 and July 2012.

RESULTS

For N. gonorrhoeae detection, the in-house PCR assay showed 98.5-100% correlation agreement with the APTIMA assays, depending on specimen type. Sensitivity for N. gonorrhoeae detection was 82.4% for ano-rectal specimens, 83.3% for oropharyngeal specimens, and 85.7% for urine; and specificity was 100% with all specimen types. The positive predictive value (PPV) for N. gonorrhoeae detection was 100% and the negative predictive value (NPV) varied with sample type, ranging from 98.5-99.5%. For C. trachomatis detection, correlation between the assays was 100% for all specimen types. The sensitivity, specificity, PPV and NPV of the in-house PCR assay was 100% for C. trachomatis detection, irrespective of specimen type.

CONCLUSION

The in-house duplex real-time PCR assay showed acceptable performance characteristics in comparison with the APTIMA® assays for the detection of extra-genital N. gonorrhoeae and C. trachomatis.

Review of Chlamydia trachomatis viability methods: assessing the clinical diagnostic impact of NAAT positive results

INTRODUCTION

Chlamydia trachomatis (chlamydia) is the most commonly diagnosed bacterial sexually transmitted infection (STI) worldwide. The advancement of molecular techniques has made chlamydia diagnostics infinitely easier. However, molecular techniques lack the information on chlamydia viability. Where in routine diagnostics the detection of chlamydia DNA or RNA might suffice, in other patient scenarios, information on the viability of chlamydia might be essential. Areas covered: In this review, the authors discuss the specific strengths and limitations of currently available methods to evaluate chlamydia viability: conventional cell culture, messenger RNA (mRNA) detection and viability-PCR (V-PCR). PubMed and Google Scholar were searched with the following terms: Chlamydia trachomatis, Treatment failure, Anal chlamydia, Microbial viability, Culture, Viability-PCR, Messenger RNA, and Molecular diagnostics Expert commentary: Several techniques are currently available to determine chlamydia viability and thus the clinical relevance of a positive test result in clinical samples. Depending on the underlying research question, all three discussed techniques have their merits when testing for viability. However, mRNA methods show the most promise in determining the presence of a true infection, in case the chlamydia reticulate body can be specifically detected. Further research is needed to understand how to best apply viability testing in current chlamydia diagnostics.

The Additive Value of Pelvic Examinations to History in Predicting Sexually Transmitted Infections for Young Female Patients With Suspected Cervicitis or Pelvic Inflammatory Disease

STUDY OBJECTIVE

We evaluate the additive value of pelvic examinations in predicting sexually transmitted infection for young female patients with suspected cervicitis or pelvic inflammatory disease in a pediatric emergency department (ED).

METHODS

This was a prospective observational study of female patients aged 14 to 20 years who presented to an urban academic pediatric ED with a complaint of vaginal discharge or lower abdominal pain. Enrolled patients provided a urine sample for chlamydia, gonorrhea, and trichomonas testing, which served as the criterion standard for diagnosis. A practitioner (pediatric ED attending physician, emergency medicine or pediatric resident, pediatric ED fellow, or advanced practice provider) obtained a standardized history from the patient to assess for cervicitis or pelvic inflammatory disease according to the Centers for Disease Control and Prevention criteria. They then recorded the likelihood of cervicitis or pelvic inflammatory disease on a 100-mm visual analog scale. The same practitioner then performed a pelvic examination and again recorded the likelihood of cervicitis or pelvic inflammatory disease on a visual analog scale with this additional information. Using the results of the urine sexually transmitted infection tests, the practitioner calculated and compared the test characteristics of history alone and history with pelvic examination.

RESULTS

Two hundred eighty-eight patients were enrolled, of whom 79 had positive urine test results for chlamydia, gonorrhea, or trichomonas, with a sexually transmitted infection rate of 27.4% (95% confidence interval [CI] 22.6% to 32.8%). The sensitivity of history alone in diagnosis of cervicitis or pelvic inflammatory disease was 54.4% (95% CI 42.8% to 65.5%), whereas the specificity was 59.8% (95% CI 52.8% to 66.4%). The sensitivity of history with pelvic examination in diagnosis of cervicitis or pelvic inflammatory disease was 48.1% (95% CI 36.8% to 59.5%), whereas the specificity was 60.7% (95% CI 53.8% to 67.3%). The information from the pelvic examination changed management in 71 cases; 35 of those cases correlated with the sexually transmitted infection test and 36 did not.

CONCLUSION

For young female patients with suspected cervicitis or pelvic inflammatory disease, the pelvic examination does not increase the sensitivity or specificity of diagnosis of chlamydia, gonorrhea, or trichomonas compared with taking a history alone. Because the test characteristics for the pelvic examination are not adequate, its routine performance should be reconsidered.

Accuracy of tests used to detect infection with Chlamydia trachomatis in asymptomatic pregnant women: a systematic review

PURPOSE OF REVIEW

Infection with Chlamydia trachomatis in pregnancy is linked to increased risk of miscarriage, stillbirth, and preterm birth. Currently, PCR or DNA-based tests are the gold standard when detecting the infection; however, they are costly and require access to specialist equipment. The aim of this systematic review was to assess the accuracy of available tests to detect infection in an asymptomatic pregnant population.

RECENT FINDINGS

There was evidence of the superior accuracy of nucleic acid amplification tests to cell culture in nonpregnant asymptomatic women; however, there are multiple commercial nucleic acid amplification tests with varying sensitivities and specificities. There is a gap in current literature on accuracy studies in an asymptomatic pregnant population, particularly within routine antenatal settings.

SUMMARY

There is a need for a point-of-care test for Chlamydia in pregnancy. Future test accuracy studies for this population should aim to use a universally established reference standard. Further research should provide relevant evidence to guide practice.

Serum antibody response to Chlamydia trachomatis TroA and HtrA in women with tubal factor infertility

Persistent genital chlamydial infection may lead to tubal factor infertility (TFI). Chlamydia trachomatis TroA and HtrA are proteins expressed during persistent chlamydial infection in vitro. We studied serum IgG antibody response against these proteins by EIA in women with TFI and in subfertile women without tubal pathology. Altogether, 22 of 258 subfertile women (8.5%) had TFI which was unilateral in 17 cases and bilateral in 5 cases. Overall, 55 (21.3%) of the 258 women had TroA and 39 (15.1%) had HtrA antibodies. Seropositivity to TroA and HtrA was more common among women with TFI than women with other causes for subfertility (45.5 vs. 19.1%, p = 0.004 for TroA; 36.4 vs. 13.1%, p = 0.004 for HtrA). Mean absorbance values and the prevalence of TroA and HtrA antibodies increased with increasing severity of TFI. On the basis of our results, TroA and HtrA serology has the potential to be further developed to a specific biomarker for C. trachomatis-related TFI.

The Chlamydia trachomatis Plasmid and CT135 Virulence Factors Are Not Essential for Genital Tract Infection or Pathology in Female Pig-Tailed Macaques

The Chlamydia trachomatis plasmid and inclusion membrane protein CT135 are virulence factors in the pathogenesis of murine female genital tract infection. To determine if these virulence factors play a similar role in female nonhuman primates, we infected pig-tailed macaques with the same C. trachomatis strains shown to be important in the murine model. Wild-type C. trachomatis and its isogenic mutant strain deficient in both plasmid and CT135 were used to infect macaques. Macaques were given primary and repeated cervicovaginal challenges with the wild-type and mutant strains. The infection rate, infection duration, and antibody response were similar among macaques infected with both strains. Unexpectedly, colposcopy, laparoscopy, and histologic analysis revealed no substantial genital tract pathology following either primary or repeated cervicovaginal challenges. Cytokine analysis of cervicovaginal secretions from both challenged groups revealed low concentrations of interleukin 1β (IL-1β) and elevated levels of the interleukin 1 receptor agonist (IL-1RA). We propose that an imbalance of IL-1β and IL-1RA in macaques is the reason for the mild inflammatory responses observed in infected urogenital tissues. Thus, understanding the pathobiology of chlamydial infection requires a better understanding of host epigenetic and chlamydial genetic factors. Our findings also have implications for understanding the high frequency of asymptomatic infections in humans.

Surface enhanced Raman spectroscopy of Chlamydia trachomatis and Neisseria gonorrhoeae for diagnostics, and extra-cellular metabolomics and biochemical monitoring

SERS spectra excited at 785 nm of the bacteria Chlamydia trahomatis (elementary bodies, EB) and Neisseria gonorrheoae, the causative pathogens for the two most common sexually transmitted diseases (STD), chlamydia and gonorrhea, respectively, are reported. Although both are Gram-negative bacteria, the SERS signatures of C. trachomatis and N. gonorrheoae are completely different. N. gonorrheoae SERS spectra are due to the starvation induced nucleotide metabolites adenine and guanine, and the surface associated co-enzyme nicotinamide adenine dinucleotide and are very similar on Au and Ag although the spectrum appears more rapidly on Ag. The C. trachomatis SERS spectrum is dominated by the vibrational features of cell surface proteins. While features attributable to specific residues and the amide backbone characterize the C. trachomatis spectrum on Ag, the corresponding SERS spectrum on Au substrates displays vibrational characteristics of aggregated proteins. The prospects for the development of a SERS based platform for rapid (<one hour), low-cost bacterial STD diagnostics are promising based on these initial studies. Furthermore, this biomedical application demonstrates the potential for SERS to be a sensitive real time probe of the dynamics of biochemical activity in the cell wall and extracellular regions of microorganisms.

Comparison of Workflow, Maintenance, and Consumables in the GeneXpert Infinity 80 and Panther Instruments While Testing for Chlamydia trachomatis and Neisseria gonorrhoeae

BACKGROUND

The 2015 Sexually Transmitted Diseases Treatment Guidelines from the Centers for Disease Control and Prevention recommend testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) using nucleic acid amplification tests, and prompt treatment of infected persons on site under direct observation. Faster time to results may enable treatment and management outcomes.

METHODS

Workflow parameters for processing 1, 10, 48, 96, and 192 tests were determined in the GeneXpert Infinity 80 (Cepheid) and Panther (Hologic) instruments.

RESULTS

In an Xpert CT/NG cartridge, the time to first results on the Infinity 80 was 1 hour 30 minutes for single or multiple tests and final results for 10, 48, 96, and 192 tests were available at 1 hour 37 minutes, 1 hour 54 minutes, 3 hour 17 minutes, and 5 hour 7 minutes, respectively. With the Aptima CT/GC assay on the Panther, the respective times were 3 hr 45 min for the first test result, and 3 hour 51 minutes, 4 hour 38 minutes, 5 hour 26 minutes, and 7 hour 4 minutes to final results. The Panther required more time for maintenance and consumed a greater variety of plastics and reagents but required less hands-on time when testing larger numbers of specimens.

CONCLUSIONS

The Infinity 80 is a versatile instrument for continuous random access testing of small or large numbers of clinical specimens and may provide diagnostic results, in some settings, in time for treatment of CT and NG infections.

Loop-mediated isothermal amplification of Neisseria gonorrhoeae porA pseudogene: a rapid and reliable method to detect gonorrhea

BACKGROUND AND OBJECTIVE

Gonorrhea is a sexually transmitted disease caused by the bacterium Neisseria gonorrhoeae. Rapid detection is crucial for effective prevention and treatment. This study developed and tested a low-cost effective method for detecting N. gonorrhoeae, especially in developing countries.

METHODS

DNA from a N. gonorrhoeae standard strain, as well as from 26 genital secretion samples of gonorrhea patients, were isolated and used for loop-mediated isothermal amplification (LAMP) assay, which was conducted using either an automatic real-time PCR analyzer or a water bath. The amplified porA pseudogene sequence was compared with the NCBI database and the LAMP results were compared with that of the traditional culture method for its sensitivity and specificity.

RESULTS

LAMP was able to detect Neisseria DNA at a concentration as low as 1 pg/µL (1 × 10³ CFU/mL cells). The LAMP assay results obtained using an automatic real-time PCR analyzer was similar to that of the water bath. Relative to traditional culture, the sensitivity and specificity of the LAMP assay were 94.7 and 85.7%, respectively.

CONCLUSION

LAMP was sensitive and reliable for detecting the porA gene of N. gonorrhoeae. It could be used as a rapid, low cost, and effective method for detecting N. gonorrhoeae.

Screening for Sexually Transmitted Infections in Adolescent Girls and Young Women in Mombasa, Kenya: Feasibility, Prevalence, and Correlates

INTRODUCTION

As adolescents and young women become sexually active, they are at risk of adverse reproductive health outcomes including sexually transmitted infections (STIs). We assessed feasibility and acceptability of STI screening among 15- to 24-year-old women in Mombasa, Kenya.

METHODS

After sensitization activities, participants were recruited from 3 high schools and 1 university. Study staff conducted informational sessions. Students interested in participating were given consent forms to take home, and invited to visit our clinic for STI screening. During clinic visits, participants completed a self-administered questionnaire and provided a urine specimen for STI testing using a nucleic acid amplification test.

RESULTS

Between August 2014 and March 2015, 463 high school and 165 university students collected consent forms. Of these, 293 (63%) from high schools versus 158 (95%) from university attended clinic for STI screening (P < 0.001). Of the 150 (33%) who reported any history of insertive vaginal sex, 78 (52.0%) reported condom use at the last sex act, 31 (20.7%) reported using modern nonbarrier contraceptive methods, and 37 (24.7%) reported not using any contraception at the last sex act. Twenty-six (5.8%) participants were diagnosed with STIs (7 [1.6%] Neisseria gonorrhoeae, 16 [3.6%] Chlamydia trachomatis, 3 [0.7%] Trichomonas vaginalis). In multivariable analyses, reporting receptive vaginal sex without a condom was associated with having a laboratory confirmed STI (odds ratio, 6.21; 95% confidence interval, 1.72-22.28).

CONCLUSIONS

These findings support the need for reproductive health interventions to reduce the risk of STIs in a population of adolescent girls and young women in East Africa.

Bayesian regression for group testing data

Group testing involves pooling individual specimens (e.g., blood, urine, swabs, etc.) and testing the pools for the presence of a disease. When individual covariate information is available (e.g., age, gender, number of sexual partners, etc.), a common goal is to relate an individual's true disease status to the covariates in a regression model. Estimating this relationship is a nonstandard problem in group testing because true individual statuses are not observed and all testing responses (on pools and on individuals) are subject to misclassification arising from assay error. Previous regression methods for group testing data can be inefficient because they are restricted to using only initial pool responses and/or they make potentially unrealistic assumptions regarding the assay accuracy probabilities. To overcome these limitations, we propose a general Bayesian regression framework for modeling group testing data. The novelty of our approach is that it can be easily implemented with data from any group testing protocol. Furthermore, our approach will simultaneously estimate assay accuracy probabilities (along with the covariate effects) and can even be applied in screening situations where multiple assays are used. We apply our methods to group testing data collected in Iowa as part of statewide screening efforts for chlamydia, and we make user-friendly R code available to practitioners.

Examining sociodemographic risk factors for Chlamydia trachomatis infection: a population-based cohort study

AIM

Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection in developed nations and is an important public health concern. We aimed to assess the factors associated with testing and positivity of C. trachomatis in a large population.

METHODS

A retrospective study of a large Canadian health region was undertaken using 2011 census and laboratory data. Demographic and socioeconomic data from the national household survey were linked to microbiologic data for C. trachomatis. Multivariable generalized estimating equation models were constructed to examine relative risk for C. trachomatis testing and positivity.

RESULTS

For testing and positivity, female sex and younger age groups were associated with increased risk. University education and South Asian ethnicity were associated with lower risk of positivity.

CONCLUSION

Incorporating socio-demographic factors will be critical to the success of future sexually transmitted infection public health programs.

Comparative Evaluation of 2 Nucleic Acid Amplification Tests for the Detection of Chlamydia trachomatis and Neisseria gonorrhoeae at Extragenital Sites

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are frequently asymptomatic, requiring highly accurate diagnostic tests and proper management to prevent further transmission. We compared two nucleic acid tests, Xpert® CT/NG (Cepheid, Sunnyvale, CA) point-of-care platform and at an offsite clinical laboratory with Aptima Combo 2® (Hologic, Inc., San Diego, CA) assay, for the detection of extragenital infection in patients at an STI clinic in Hollywood, CA.We calculated concordance between the two assays and used the exact binomial method to calculate 95% confidence intervals (CIs) for each specimen type and pathogen.The concordance between the two assays was 97.7% (95% CI: 95.7%,99.0%) for 393 paired CT rectal results, 98.2% (95% CI: 96.4%,99.3%) for 391 paired NG rectal results and 98.4% (95% CI: 96.8%,99.4%) for 448 paired NG pharyngeal results.The performance of Xpert® CT/NG assay in point-of-care testing in extragenital specimens was highly similar to the laboratory-based platform.

Prevalence and clinical correlates of chlamydia infection in youth who use drugs and alcohol: a good opportunity for early intervention

AIMS

This study estimates the prevalence of chlamydia infection amongst teenage substance users aged 14-18years and investigates risk factors associated with a positive diagnosis of chlamydia infection.

METHODS

Data was collected from the medical files of adolescents who attended a statewide drug and alcohol treatment facility during a three-year period commencing June 2011.

RESULTS

The highest rate of chlamydia detection (18.0%) was found in the group with a reported history of abuse, a non-substance use psychiatric diagnosis, and individuals who did not complete year 10 education.

CONCLUSION

Adolescents attending a detoxification facility are a suitable group for targeted chlamydia infection screening and early treatment.

Stability Studies on Dry Swabs and Wet Mailed Swabs for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Aptima Assays

The Aptima Combo 2 (AC2) and Aptima CT (ACT) (Hologic Inc., San Diego, CA) are nucleic acid amplification tests (NAATs) that detect Chlamydia trachomatis AC2 also detects Neisseria gonorrhoeae Storage and temperature conditions may impact the utility of NAATs in some settings and screening programs. We evaluated specimen stability for use beyond the Aptima package insert specifications for temperature and duration of storage (between 2°C and 30°C and 60 days, respectively) in two studies: (i) dry C. trachomatis-seeded swabs were used with ACT after storage at 4°C, 23°C, or 36°C for up to 84 days and (ii) swabs seeded with C. trachomatis and N. gonorrhoeae and then placed in transport medium were tested with AC2, after being mailed via the U.S. Postal Service to three different sites. Prolonged storage of samples had no effect, and samples stored at 4°C, 23°C, and 36°C for up to 84 days yielded comparable ACT positivities, although there was a drop in signal intensity for virtually all specimens under all storage/shipping conditions after day 21. In the mailing study, 80%, 52% and 29% of seeded swabs were exposed to temperatures of >30°C during three rounds in transit, and 2% reached temperatures of >40°C. No evidence of signal degradation in the AC2 assay for detection of C. trachomatis or N. gonorrhoeae was observed, although some mailed swabs took more than 5 weeks to reach the laboratory site. These two studies support the potential use of swabs at temperatures above 36°C and storage beyond 60 days and provide confidence regarding this commercially available NAAT for testing of specimens after mailing.

Self-collected glans/meatal 'dry' swab specimen and NAAT technology detects Chlamydia trachomatis and Neisseria gonorrhoeae - implications for public policy changes

Increasing Chlamydia trachomatis (CT) rates and ever-present Neisseria gonorrhoeae (NG) infections in women have given rise in the past to consideration of male screening programs in order to address the silent male reservoir. Non-medical venues (e.g. home collection, restrooms or other private locations) may be viable venues to reach certain populations that in the past have not been accessed. Effortlessly collected, non-invasive, self-collected male specimens that are stable and easy to transport would enhance the success of male screening programs. We designed a head-to-head study to consider the effectiveness of non-invasive self-collected glans/meatal dry swab (SCS) specimens to detect CT and NG nucleic acid when compared to traditional clinician-collected swab (CCS) specimens and first-catch urine (FCU) specimens. A total of 284 male patients were included in the study. Specimens were processed using the Becton Dickinson ProbeTec ET system. The overall sensitivity of SCS was 91.1% with a specificity of 99.2%. There was an overall SCS agreement of 97.7% with CCS specimens and 90.4% with FCU specimens. Dry swab specimens are easy to collect, transport and test. Non-invasive dry self-collected glans/meatal swab specimens are a viable specimen choice.

Examining Chlamydia trachomatis and Neisseria gonorrhoeae rates between 2010 and 2015: a population-based observational study

Bacterial sexually transmitted infections including Chlamydia trachomatis and Neisseria gonorrhoeae remain an important public health concern. We aimed to assess the population-based incidence of C. trachomatis and N. gonorrhoeae in an age-standardized cohort over time. A retrospective study of a large Canadian health region was undertaken between 2010 and 2015 using linked census and digital laboratory data. C. trachomatis and N. gonorrhoeae tests were linked to patient data. Sex and age-standardized incidence rates (IR) and ratios (IRR) were calculated for cases and testing rates. The annual mean population was 1,150,556 individuals (50.1% female). A total of 15,109 cases of chlamydia and 981 cases of gonorrhoea occurred. The overall IR for chlamydia ranged from 18.81 to 25.63 cases per 10,000 person-years. The IRR was 1.27 (95% CI 1.20-1.34, p < 0.001) for the comparison of 2015 and 2010 rates. For gonorrhoea, overall rates ranged from 0.92 to 1.86 cases per 10,000 person-years. The IRR for gonorrhoea was 2.02 (95% CI 1.56-2.59, p < 0.001) for 2015 and 2010 rates. In our large population-based study spanning six years, we observed increasing rates of C. trachomatis and N. gonorrhoeae with low testing rates.

Translating diagnostic assays from the laboratory to the clinic: analytical and clinical metrics for device development and evaluation

As lab-on-a-chip health diagnostic technologies mature, there is a push to translate them from the laboratory to the clinic. For these diagnostics to achieve maximum impact on patient care, scientists and engineers developing the tests should understand the analytical and clinical statistical metrics that determine the efficacy of the test. Appreciating and using these metrics will benefit test developers by providing consistent measures to evaluate analytical and clinical test performance, as well as guide the design of tests that will most benefit clinicians and patients. This paper is broken into four sections that discuss metrics related to general stages of development including: (1) laboratory assay development (analytical sensitivity, limit of detection, analytical selectivity, and trueness/precision), (2) pre-clinical development (diagnostic sensitivity, diagnostic specificity, clinical cutoffs, and receiver-operator curves), (3) clinical use (prevalence, predictive values, and likelihood ratios), and (4) case studies from existing clinical data for tests relevant to the lab-on-a-chip community (HIV, group A strep, and chlamydia). Each section contains definitions of recommended statistical measures, as well as examples demonstrating the importance of these metrics at various stages of the development process. Increasing the use of these metrics in lab-on-a-chip research will improve the rigor of diagnostic performance reporting and provide a better understanding of how to design tests that will ultimately meet clinical needs.