Point-of-care tests to reduce the burden of sexually transmitted infections

Activatable G-quadruplex based catalases for signal transduction in biosensing

Discovery of oxidative catalysis with G-quadruplex•hemin constructs prompted a range of exciting developments in the field of biosensor design. Thus, G-quadruplex based DNAzymes with peroxidase activity found a niche as signal transduction modules in a wide range of analytical applications. The ability of nucleic acid scaffolds to recognise a variety of practically meaningful markers and to translate the recognition events into conformational changes powers numerous sensor design possibilities. In this work, we establish a catalase activity of G-quadruplex•hemin scaffolds. Catalase activated hydrogen peroxide decomposition generates molecular oxygen that forms bubbles. Observation of bubbles is a truly equipment free signal readout platform that is highly desirable in limited resources or do-it-yourself environments. We take a preliminary insight into a G-quadruplex structure-folding topology-catalase activity correlation and establish efficient operating conditions. Further, we demonstrate the platform's potential as a signal transduction modality for reporting on biomolecular recognition using an oligonucleotide as a proof-of-concept target. Ultimately, activatable catalases based on G-quadruplex•hemin scaffolds promise to become valuable contributors towards accessible molecular diagnostics applications.

Syndromic Treatment of STIs in Low-income Countries is Inadequate: Current Threats and Future Directions

Sexually transmitted infections (STIs) pose a serious public health threat with more than 1 million curable infections diagnosed every day. While these infections are prevalent globally, the approach to evaluation and treatment varies greatly based on the capacity to make an accurate diagnosis. In low-resource settings, a syndromic approach is often used over an etiologic-based evaluation and management. Syndromic treatment of STIs recognizes groups of symptoms and recommends a multidrug empiric treatment that will cover the most likely causative organisms. By definition, syndromic treatment cannot be used as a screening tool, leaving a large portion of asymptomatic infections untreated. This will lead to the persistence of infection and associated sequelae including pelvic inflammatory disease and infertility. Syndromic treatment also leads to the overtreatment of many infections, which contributes to antimicrobial resistance. The rising threat of Neisseria gonorrhoeae resistance to last-line antibiotics is of global concern. Rapid, accurate, affordable, and easy-to-use point-of-care testing needs to be made readily available to all corners of the world to provide better care to patients and address the growing threat of multidrug resistant organisms. An urgent and collaborative global effort is needed to address the looming threat of a dangerous STI that is resistant to last-line antibiotics.

Facilitators and barriers to point-of-care testing for sexually transmitted infections in low- and middle-income countries: a scoping review

Background

Sexually transmitted infections (STIs) in low- and middle-income countries (LMICs) are predominantly managed by syndromic management. However, most STIs are asymptomatic. These untreated STIs cause individual morbidity, and lead to high STI prevalences.

There is increasing interest in the use of point-of-care tests (POCTs) for STIs in LMICs, which could facilitate same day testing and treatment. To best utilise these tests, we must understand the facilitators and barriers to their implementation. The aim of this review is to explore how point-of-care testing for STIs has been implemented into healthcare systems in LMIC and the facilitators and barriers to doing so.

Methods

A scoping review was conducted by searching MEDLINE, Embase, Emcare, CINAHL, Scopus, LILACS, the Cochrane Library, and ProQuest Dissertations and Theses for studies published between 1st January 1998 and 5th June 2020. Abstracts and full articles were screened independently by two reviewers. Studies were considered for inclusion if they assessed the acceptability, feasibility, facilitators, or barriers to implementation of point-of-care testing for chlamydia, gonorrhoea, trichomoniasis or syphilis in LMICs. Thematic analysis was used to analyse and present the facilitators and barriers to point-of-care STI testing.

Results

The literature search revealed 82 articles suitable for inclusion; 44 (53.7%) from sub-Saharan Africa; 21 (25.6%) from Latin American and the Caribbean; 10 (12.2%) from East Asia and the Pacific; 6 (7.3%) from South Asia; and one (1.2%) multi-regional study. Thematic analysis revealed seven overarching themes related to the implementation of POCTs in LMICs, namely (i) Ideal test characteristics, (ii) Client factors, (iii) Healthcare provision factors, (iv) Policy, infrastructure and health system factors, (v) Training, audit, and feedback, (vi) Reaching new testing environments, and (vii) Dual testing.

Conclusion

Implementation of POCTs in LMICs is complex, with many of the barriers due to wider health system weakness. In addition to pressing for broader structural change to facilitate basic healthcare delivery, these themes may also be used as a basis on which to develop future interventions. The literature was heavily skewed towards syphilis testing, and so more research needs to be conducted assessing chlamydia, gonorrhoea, and trichomoniasis testing, as well as home or self-testing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07534-9.

Point-of-care testing for sexually transmitted infections in low- and middle-income countries: a scoping review protocol

OBJECTIVE

This review will explore how point-of-care tests for sexually transmitted infections have been implemented into health care systems in low- and middle-income countries, and the facilitators and barriers to implementation.

INTRODUCTION

Sexually transmitted infections contribute to significant global morbidity. In low- and middle-income countries, syndromic management of sexually transmitted infections is recommended. However, due to the limitations of syndromic management, there is increasing interest in the potential for point-of-care tests to be incorporated into models of care for sexually transmitted infections in low-resource settings. It is therefore important to explore how point-of-care tests for sexually transmitted infections have been used in these settings previously, and the facilitators and barriers to implementation on a wider scale.

INCLUSION CRITERIA

This scoping review will consider studies that explore the use of point-of-care-testing for chlamydia, gonorrhea, trichomoniasis, or syphilis, and how they are implemented into models of care in low- and middle-income countries. Study participants may be those receiving sexually transmitted infection testing or health care professionals providing testing. HIV testing will not be covered. Quantitative, qualitative, and mixed methods study designs, as well as review papers will be considered for inclusion.

METHODS

The proposed scoping review will be conducted in accordance with JBI methodology for scoping reviews. The authors will search databases including MEDLINE, Embase, Emcare, CINAHL, Scopus, LILACS, African Index Medicus, and the Cochrane library from 1998 onwards. Results will be screened by two independent reviewers and data extracted using a data extraction tool developed by the reviewers. Data will be presented both narratively and in tabular form.

Diagnosing sexually transmitted infections in resource-constrained settings: challenges and ways forward

INTRODUCTION

Sexually transmitted infections (STIs) remain prevalent and are increasing in several populations. Appropriate STI diagnosis is crucial to prevent the transmission and sequelae of untreated infection. We reviewed the diagnostic accuracy of syndromic case management and existing point-of-care tests (POCTs), including those in the pipeline, to diagnose STIs in resource-constrained settings.

METHODS

We prioritized updating the systematic review and meta-analysis of the diagnostic accuracy of vaginal discharge from 2001 to 2015 to include studies until 2018. We calculated the absolute effects of different vaginal flowcharts and the diagnostic performance of POCTs on important outcomes. We searched the peer-reviewed literature for previously conducted systematic reviews and articles from 1990 to 2018 on the diagnostic accuracy of syndromic management of vaginal and urethral discharge, genital ulcer and anorectal infections. We conducted literature reviews from 2000 to 2018 on the existing POCTs and those in the pipeline.

RESULTS AND DISCUSSIONS

The diagnostic accuracy of urethral discharge and genital ulcer disease syndromes is relatively adequate. Asymptomatic Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections limit the use of vaginal discharge and anorectal syndromes. The pooled diagnostic accuracy of vaginal syndromic case management for CT/NG is low, resulting in high numbers of overtreatment and missed treatment. The absolute effect of POCTs was reduced overtreatment and missed treatment. Findings of the reviews on syndromic case management underscored the need for low-cost and accurate POCTs for the identification, first, of CT/NG, and, second, of Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV) and NG and MG resistance/susceptibility testing. Near-patient POCT molecular assays for CT/NG/TV are commercially available. The prices of these POCTs remain the barrier for uptake in resource-constrained settings. This is driving the development of lower cost solutions.

CONCLUSIONS

The WHO syndromic case management guidelines should be updated to raise the quality of STI management through the integration of laboratory tests. STI screening strategies are needed to address asymptomatic STIs. POCTs that are accurate, rapid, simple and affordable are urgently needed in resource-constrained settings to support the uptake of aetiological diagnosis and treatment.