Poor Performance of the Chlamydia Rapid Test Device for the Detection of Asymptomatic Infections in South African Men: A Pilot Study

Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review

Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.

Diagnosis and Management of Uncomplicated Chlamydia trachomatis Infections in Adolescents and Adults: Summary of Evidence Reviewed for the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines

To prepare for the development of the 2021 Centers for Disease Control and Prevention (CDC) sexually transmitted infections treatment guidelines, the CDC convened a committee of expert consultants in June 2019 to discuss recent abstracts and published literature on the epidemiology, diagnosis, and management of sexually transmitted infections.This paper summarizes the key questions, evidence, and recommendations for the diagnosis and management of uncomplicated Chlamydia trachomatis (CT) infections in adolescents and adults that were reviewed and discussed for consideration in developing the guidelines. The evidence reviewed mostly focused on efficacy of doxycycline and azithromycin for urogenital, rectal, and oropharyngeal CT infection, CT risk factors in women, performance of CT nucleic acid amplification tests on self-collected meatal specimens in men, and performance of newer CT point-of-care tests.

Performance of point-of-care tests for the detection of chlamydia trachomatis infections: A systematic review and meta-analysis

BACKGROUND

Chlamydia trachomatis (CT) is one of the most prevalent bacterial sexually transmitted infections (STIs) globally but has been inadequately detected for intervention. Introduction of point-of-care tests (POCTs) for CT is critical for filling the intervention gaps. We conducted a systematical review and meta-analysis on diagnostic performance of POCTs for CT to assist in guiding the application of these assays in CT screening and detection.

METHODS

We searched PubMed/Medline and Embase databases, from January 2004 to May 2021, for studies reporting the performance of POCTs for identifying CT using specimens collected from urethral, vaginal, cervical, anorectal, or pharyngeal site or of urine. Two investigators independently screened and extracted data for controlling the quality of data extraction. Any discrepancies in study selection and data extraction were resolved through consensus. We only included studies with sufficient data to estimate sensitivity and specificity, and used laboratory-based nucleic acid amplification test (NAAT) as the reference standard. The main outcomes were pooled sensitivity, specificity, and diagnostic odds ratio (DOR) and their corresponding 95% confidence intervals (CIs). Summary estimates were calculated using a random-effects model and summary receiver operator curves (SROCs) were generated using the Moses-Littenberg method. STATA 14.0 and Meta-DiSc 1.4 were used for statistical analysis. The study protocol is registered with PROSPERO, number CRD42019140544.

FINDINGS

Of 3,038 records identified, 39 studies (42,336 specimens) were included in the study, including 14 studies on evaluation of antigen detection (AD)-based and 25 on NAAT-based POCTs. The overall pooled sensitivity, specificity and DOR were 56% (95% CI 45%-67%), 99% (95% CI 98%-99%) and 86 (95% CI 46-163), respectively, for AD-based POCTs and corresponding values for NAAT-based POCTs were 94% (95% CI 91%-96%), 99% (95% CI 99%-99%) and 1,933(95% CI 1,018-3,669), respectively. The pooled sensitivity of AD-based POCTs varied across the types of specimens, indicating 46% for cervical swabs (95% CI 37%-56%; range 22.7%-71.4%), 52% for vaginal swabs (95% CI 34%-70%; range 17.1%-86.8%) and 57% for male urine (95% CI 36%-75%; range 20.0%-82.6%). For NAAT-based POCTs, the pooled sensitivity was 94% (95% CI 90%-96%) for cervical swabs, 94% (95% CI 86%-98%) for vaginal swabs, 95% (95% CI 91%-97%) for urine specimens and 93% (95% CI 87%-96%) for anorectal swabs.

INTERPRETATION

NAAT-based POCTs for CT have a significantly better performance particularly in sensitivity for diagnosing the infection with CT than the AD-based POCTs. Screening strategy with AD-based POCTs may potentially result in a substantial under-detection of the infections.

Rapid point of care test for detecting urogenital Chlamydia trachomatis infection in nonpregnant women and men at reproductive age

BACKGROUND

Chlamydia trachomatis (C trachomatis) is one of the most frequent sexually transmitted infections and a source of deleterious effects on the reproductive health of men and women. Because this infection is likely asymptomatic and is associated with subfertility, ectopic pregnancy, and chronic pain, its presence needs to be confirmed. Technologies available for the diagnosis of C trachomatis infection can be classified into tests performed in a laboratory and rapid tests at the point of care (POC tests). Laboratory-based tests include culture, nucleic acid amplification tests, enzyme immunoassays (EIA), direct fluorescent antibody, nucleic acid hybridization, and transformation tests. Rapid tests include solid-phase EIA and solid-phase optical immunoassay. POC tests can be performed within 30 minutes without the need for expensive or sophisticated equipment. The principal advantage of this technology is the immediate presentation of results with the subsequent possibility to start the treatment of infected patients immediately.

OBJECTIVES

To determine the diagnostic accuracy of rapid point-of-care (POC) testing for detecting urogenital C trachomatis infection in nonpregnant women and men of reproductive age, as verified with nucleic acid amplification tests (NAATs) as the reference standard.

SEARCH METHODS

In November 2019 we searched CENTRAL, MEDLINE, Embase and LILACS. We also searched Web of Science, two trials registries and an abstract database. We screened reference lists of included studies for additional references.

SELECTION CRITERIA

We included diagnostic accuracy studies of symptomatic or asymptomatic nonpregnant women and men reproductive age. Included trials should have prospectively enrolled participants without previous diagnostic testing, co-infections or complications and consecutively or through random sampling at primary or secondary care facilities. Only studies reporting that all participants received the index test and the reference standard and presenting 2 x 2 data were eligible for inclusion. We excluded diagnostic case-control studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Two review authors independently, and in duplicate, assessed eligibility, extracted data, and carried out quality assessment. We resolved differences through consensus or by involving a third review author. We assessed studies for methodological quality using QUADAS-2 and used meta-analysis to combine the results of studies using the bivariate approach to estimate the expected sensitivity and specificity values. We assessed the quality of the evidence using GRADE criteria and explored sources of heterogeneity.

MAIN RESULTS

We included a total of 19 studies, with 13,676 participants, that assessed the diagnostic accuracy of POC tests for C trachomatis infection in nonpregnant women and men of reproductive age, as verified with NAATs as the reference standard. Rapid tests were provided by the distributors in nine studies. Seven studies recruited a predominantly high risk or symptomatic population; the studies were conducted in America, Asia, Africa, Europe and Oceania, with a median prevalence of 10% (range 8% to 28%); nine different brands were assessed. The mean sensitivity for rapid tests for detecting urogenital infection was 0.48 (95% confidence interval (CI) 0.39 to 0.58; low-quality evidence) with a mean specificity of 0.98 (95% CI 0.97 to 0.99; moderate-quality evidence). We explored sources of heterogeneity by looking into differences in diagnostic accuracy according to the specimen (endocervical versus urine or vaginal), symptoms among participants (symptomatic versus asymptomatic), and setting (low/middle-income versus high-income countries). Likelihood ratio tests were not significantly different in terms of sensitivity or specificity by specimen (P = 0.27) or setting (P = 0.28); for this reason, these covariates do not appear to explain the observed variability. Included studies did not provide enough information to assess the 'presence of symptoms' covariate. We downgraded the quality of evidence because of some limitations in applicability and heterogeneity.

AUTHORS' CONCLUSIONS

Based on the results of this systematic review, the POC test based on antigen detection has suboptimal sensitivity but good specificity. Performance of this test translates, on average, to a 52% chance of mistakenly indicating absence of infection and a 2% chance of mistakenly pointing to the presence of this condition. Because of its deleterious consequences for reproductive health, and considering the current availability of safe and effective interventions to treat C trachomatis infection, the POC screening strategy should not be based on a rapid diagnostic test for antigen detection. Research in this topic should focus on different technologies.

A hybrid design testing a 3-step implementation model for community scale-up of an HIV prevention intervention in rural Malawi: study protocol

BACKGROUND

Scaling-up evidence-based behavior change interventions can make a major contribution to meeting the UNAIDS goal of no new HIV infections by 2030. We developed an evidence-based peer group intervention for HIV prevention and testing in Malawi that is ready for wider dissemination. Our innovative approach turns over ownership of implementation to rural communities. We adapted a 3-Step Implementation Model (prepare, roll-out and sustain) for communities to use. Using a hybrid design, we simultaneously evaluate community implementation processes and program effectiveness.

METHODS

Three communities in southern Malawi begin implementation in randomly-assigned order using a stepped wedge design. Our evaluation sample size of 144 adults and 144 youth per community provides sufficient power to examine primary outcomes of condom use and HIV testing. Prior to any implementation, the first participants in all three communities are recruited and complete the Wave 1 baseline survey. Waves 2-4 surveys occur after each community completes roll-out. Each community follows the model's three steps. During Prepare, the community develops a plan and trains peer group leaders. During Roll-Out, peer leaders offer the program. During Sustain, the community makes and carries out plans to continue and expand the program and ultimately obtain local funding. We evaluate degree of implementation success (Aim 1) using the community's benchmark scores (e.g, # of peer groups held). We assess implementation process and factors related to success (Aim 2) using repeated interviews and observations, benchmarks from Aim 1 and fidelity assessments. We assess effectiveness of the peer group intervention when delivered by communities (Aim 3) using multi-level regression models to analyze data from repeated surveys. Finally, we use mixed methods analyses of all data to assess feasibility, acceptability and sustainability (Aim 4).

DISCUSSION

The project is underway, and thus far the first communities have enthusiastically begun implementation. We have had to make several modifications along the way, such as moving from rapid-tests of STIs to symptoms screening by a nurse due to problems with test reliability and availability. If successful, results will provide a replicable evidence-based model for future community implementation of this and other health interventions.

TRIAL REGISTRATION

Clinical Trials.gov NCT02765659 Registered May 6, 2016.

Diagnostic Procedures to Detect Chlamydia trachomatis Infections

The intracellular life style of chlamydia and the ability to cause persistent infections with low-grade replication requires tests with high analytical sensitivity to directly detect C. trachomatis (CT) in medical samples. Nucleic acid amplification tests (NAATs) are the most sensitive assays with a specificity similar to cell culture and are considered the method of choice for CT detection. In addition, NAATs can be performed on various clinical specimens that do not depend on specific transport and storage conditions, since NAATs do not require infectious bacteria. In the case of lower genital tract infections, first void urine and vaginal swabs are the recommended specimens for testing males and females, respectively. Infections of anorectal, oropharyngeal and ocular epithelia should also be tested by NAAT analysis of corresponding mucosal swabs. In particular, anorectal infections of men who have sex with men (MSM) should include evaluation of lymphogranuloma venereum (LGV) by identification of genotypes L1, L2 or L3. Detection of CT antigens by enzyme immunoassay (EIAs) or rapid diagnostic tests (RDTs) are unsuitable due to insufficient sensitivity and specificity. Recent PCR-based RDTs, however, are non-inferior to standard NAATs, and might be used at the point-of-care. Serology finds application in the diagnostic work-up of suspected chronic CT infection but is inappropriate to diagnose acute infections.