Auditing the use and assessing the clinical utility of microscopy as a point-of-care test for Neisseria gonorrhoeae in a Sexual Health clinic

Highly specific detection of Neisseria gonorrhoeae based on recombinase polymerase amplification-initiated strand displacement amplification

Neisseria gonorrhoeae is the only pathogen that causes gonorrhea, and can have serious consequences if left untreated. A simple and accurate detection method for N. gonorrhoeae is essential for the diagnosis of gonorrhea and the appropriate prescription of antibiotics. The application of isothermal recombinase polymerase amplification (RPA) to detect this pathogen is advantageous because of its rapid performance, high sensitivity, and minimal dependency on equipment. However, this simplicity is offset by the risk of false-positive signals from primer-dimers and primer-probe dimers. In this study, RPA-initiated strand displacement amplification (SDA) was established for the detection of N. gonorrhoeae, and eliminated false-positive signals from primer-dimers and primer-probe dimers. The developed biosensor allows for the reduced generation of nonspecific RPA amplification through the design of enzyme cleavage sites on primers, introduction of SDA, and detection of the final product using a molecular beacon (MB). Using this system, the DNA double strand is transformed into single-stranded DNA following SDA, thereby providing a more suitable binding substrate and improving the efficiency of MB detection. Amplification can be conducted below 37 °C, and the process can be completed within 90 min. The limit of detection was determined to be 0.81 copies/μL. This system is highly specific for N. gonorrhoeae and exhibits no cross-reactivity with other common urogenital pathogens. The results of this study are consistent with those of real-time PCR performed on clinical specimens of urogenital secretions. In summary, the biosensor is a simple and specific detection method for N. gonorrhoeae.

Abnormal vaginal discharge among women of reproductive age in sub-Saharan Africa: the need for a paradigm shift from a syndromic approach to specific pathogen identification and directed treatment

Background

An abnormal vaginal discharge is a frequent manifestation of reproductive tract infections, including sexually transmitted infections (STIs) and vulvovaginal candidiasis. It is also a manifestation of bacterial vaginosis, which has a prevalence of up to 50% among women of reproductive age. Reproductive tract infections are associated with a range of reproductive health challenges and increase the risk of HIV acquisition.

Methods

This study was performed to critically review and discuss the current diagnostic and treatment approaches to abnormal vaginal discharge among women of reproductive age in sub-Saharan Africa, and to call for a paradigm shift from the syndromic approach to specific pathogen identification and directed antimicrobial therapy.

Discussion

Young women have the highest incidence of HIV infection in sub-Saharan Africa. Countries in sub-Saharan Africa where the prevalence of both STIs and bacterial vaginosis is very high have been employing a syndromic approach for the treatment of abnormal vaginal discharge since around 1984. However, the syndromic approach has several limitations, with the potential to miss infections, over-diagnose and over-treat STIs, and propagate antimicrobial resistance, which is one of the greatest global health challenges of the 21st century.

Conclusions

The low to middle-income countries of sub-Saharan Africa must innovate and leverage improved diagnostics to capacitate primary health care and other levels for point-of-care diagnostic testing, in order to provide an immediate diagnosis and treatment for women with an abnormal vaginal discharge.

Applying a novel approach to scoping review incorporating artificial intelligence: mapping the natural history of gonorrhoea

BACKGROUND

Systematic and scoping literature searches are increasingly resource intensive. We present the results of a scoping review which combines the use of a novel artificial-intelligence-(AI)-assisted Medline search tool with two other 'traditional' literature search methods. We illustrate this novel approach with a case study to identify and map the range of conditions (clinical presentations, complications, coinfections and health problems) associated with gonorrhoea infection.

METHODS

To fully characterize the range of health outcomes associated with gonorrhoea, we combined a high yield preliminary search with a traditional systematic search, then supplemented with the output of a novel AI-assisted Medline search tool based on natural language processing methods to identify eligible literature.

RESULTS

We identified 189 health conditions associated with gonorrhoea infection of which: 53 were identified through the initial 'high yield' search; 99 through the systematic search; and 124 through the AI-assisted search. These were extracted from 107 unique references and 21 International Statistical Classification of Diseases and Related Health Problems Ninth and Tenth Revision (ICD 9/10) or Read codes. Health conditions were mapped to the urogenital tract (n = 86), anorectal tract (n = 6) oropharyngeal tract (n = 5) and the eye (n = 14); and other conditions such as systemic (n = 61) and neonatal conditions (n = 7), psychosocial associations (n = 3), and co-infections (n = 7). The 107 unique references attained a Scottish Intercollegiate Guidelines Network (SIGN) score of ≥2++ (n = 2), 2+ (14 [13%]), 2- (30 [28%]) and 3 (45 [42%]), respectively. The remaining papers (n = 16) were reviews.

CONCLUSIONS

Through AI screening of Medline, we captured - titles, abstracts, case reports and case series related to rare but serious health conditions related to gonorrhoea infection. These outcomes might otherwise have been missed during a systematic search. The AI-assisted search provided a useful addition to traditional/manual literature searches especially when rapid results are required in an exploratory setting.

Visual and Rapid Diagnosis of Neisseria gonorrhoeae Using Loop-Mediated Isothermal Amplification Combined With a Polymer Nanoparticle-Based Biosensor in Clinical Application

Neisseria gonorrhoeae is a host-adapted human pathogen that causes sexually transmitted gonorrhea and remains to be a serious global public health challenge, especially in low- and middle-income regions. It is vital to devise a reliable, simple, cost-saving, and easy-to-use assay for detecting the N. gonorrhoeae agent. In the current study, we firstly report a novel approach, loop-mediated isothermal amplification linked with a polymer nanoparticle-based biosensor (LAMP-PNB), that was used for identifying N. gonorrhoeae in clinical samples. The results showed that the LAMP primers based on the orf1 gene were valid for development of the N. gonorrhoeae-LAMP-PNB assay. The detection system with optimal conditions could be performed at a fixed temperature of 64°C for 40 min. The whole process, including genomic DNA preparation (approximately 10 min), LAMP reaction (40 min), and PNB reporting (approximately 2 min), could be accomplished within 60 min. The limit of detection (LoD) of the N. gonorrhoeae-LAMP-PNB assay was 50 copies per test. The specificity of the current assay was 100%, and no cross-reactions to non-N. gonorrhoeae isolates were observed. These results confirmed that the N. gonorrhoeae-LAMP-PNB technique is a reliable, specific, sensitive, rapid, low-cost, and easy-to-use method for detecting gonococci isolates. More importantly, this assay has great potential to develop a point-of-care (POC) testing method in clinical practice, especially in resource-constrained regions.

Empirical treatment of asymptomatic contacts of gonorrhoea: patient views

Background The prevalence of Neisseria gonorrhoeae (gonorrhoea) in sexual contacts of gonorrhoea has not been established, but limited data suggest that the majority of contacts are not infected. Contacts of gonorrhoea who receive empirical treatment at the point of testing may receive unnecessary antimicrobial treatment for an infection that is known to have multidrug resistance. This study evaluated patient acceptability of non-empirical treatment.?

METHODS

We conducted an anonymous cross-sectional survey of patients attending sexual health centres in New South Wales, Australia, on the acceptability of empirical and non-empirical treatment models and patients' concerns about antimicrobial resistance.

RESULTS

Most of the 823 survey participants were willing to wait for treatment until their results were reported; 77% and 53% would agree to wait for treatment if results were available in 2 and 7 days respectively. Participants were less likely to agree to non-empirical treatment if they lived in regional and remote areas compared with those in a major city (odds ratio (OR) 0.5; 95% confidence interval (CI) 0.35-0.73). Most participants (70%) were worried about infections becoming resistant to antibiotics, with heterosexual men and women being less likely than gay and bisexual men to be worried (heterosexual men: OR 0.64, 95% CI 0.44-0.94; women: OR 0.64 95%, CI 0.44-0.92).

CONCLUSIONS

Non-empirical treatment was acceptable to most participants, but patient preference, ability to return for treatment and timeliness of results are factors that should inform individual treatment decisions.

Epidemiologic Treatment for Contacts to Neisseria gonorrhoeae and Chlamydia trachomatis Infection in Sexually Transmitted Disease Clinic Patients in Seattle, WA; 1994 to 2018

INTRODUCTION

Current Centers for Disease Control and Prevention guidelines recommend that clinicians empirically treat the sex partners of persons with Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT) infection before confirming that they are infected. It is possible that this practice, known as epidemiologic treatment, results in overtreatment for uninfected persons and may contribute to development of antimicrobial resistance. We sought to quantify the number of patients who received epidemiologic treatment and the proportion of those who were overtreated.

METHODS

We reviewed records from a municipal sexually transmitted disease clinic in Seattle, WA, from 1994 to 2018 to identify visits by asymptomatic patients seeking care because of sexual contact to a partner with GC and/or CT. We defined overtreatment as receipt of antibiotic(s) in the absence of a positive GC/CT test result and calculated the proportions of contacts epidemiologically treated and tested positive for GC/CT and overtreated in five 5-year periods stratified by sex and gender of sex partner. We used the Cochran-Armitage test to assess for temporal trends.

RESULTS

The number of asymptomatic contacts epidemiologically treated for GC/CT increased from 949 to 3159 between the 1994-1998 and 2014-2018 periods. In 2014-2018, 55% of persons were overtreated, most (82.1%) of these were men who have sex with men (MSM). The proportion of MSM overtreated decreased from 74% to 65% (P < 0.01), but the total number of overtreated MSM increased from 172 to 1428.

DISCUSSION

A high proportion of persons receiving epidemiologic treatment of GC/CT are uninfected. The current practice of routinely treating all sex partners of persons with GC/CT merits reconsideration in light of growing antimicrobial resistance.

The Laboratory Diagnosis of Neisseria gonorrhoeae: Current Testing and Future Demands

The ideal laboratory test to detect Neisseria gonorrhoeae (Ng) should be sensitive, specific, easy to use, rapid, and affordable and should provide information about susceptibility to antimicrobial drugs. Currently, such a test is not available and presumably will not be in the near future. Thus, diagnosis of gonococcal infections presently includes application of different techniques to address these requirements. Microscopy may produce rapid results but lacks sensitivity in many cases (except symptomatic urogenital infections in males). Highest sensitivity to detect Ng was shown for nucleic acid amplification technologies (NAATs), which, however, are less specific than culture. In addition, comprehensive analysis of antibiotic resistance is accomplished only by in vitro antimicrobial susceptibility testing of cultured isolates. As a light at the end of the tunnel, new developments of molecular techniques and microfluidic systems represent promising opportunities to design point-of-care tests for rapid detection of Ng with high sensitivity and specificity, and there is reason to hope that such tests may also provide antimicrobial resistance data in the future.

Provider attitudes to the empiric treatment of asymptomatic contacts of gonorrhoea

Background In the current era of antimicrobial stewardship, the availability of highly sensitive assays and faster turnaround times, the practice of empiric treatment of asymptomatic contacts of gonorrhoea needs review. The views of clinicians in a range of settings across Australia and clinic costs associated with a change of practice was examined. Methods: An online anonymous survey for nurses and doctors working in public sexual health clinics and general practices in urban, regional and rural Australia was developed. Information on the relative importance of a range of factors influencing delivery of empiric treatment was collected. Participants were asked whether current guidelines should change. Results: Surveys were distributed to 468 healthcare providers and 188 (40.2%) fully completed the survey. Most of the participants worked in public practice (84.9%) and 86 (43.2%) were doctors. Factors influencing provision of empiric treatment were: if the patient was unable to return (95.9%) or may not return (95.3%); risk of transmission to others (93.3%); likelihood of infection (88.6%); and patient request (82.9%). Respondents were evenly split as to whether current guidelines should change, with providers in private practice being less likely to support guideline change (P = 0.03). The model of empiric treatment of all asymptomatic sexual contacts was 34% more expensive than a model of testing and treatment of those with a positive result. Conclusion: Currently, the majority of clinicians provide empiric treatment for asymptomatic contacts in Australia. There was significant support for a change in guidelines with specific scenarios requiring individualised responses.