Multiplex PCR testing for nine different sexually transmitted infections

Nucleic acid hybridization-based detection of pathogenic RNA using microscale thermophoresis

Infectious diseases are one of the world's leading causes of morbidity. Their rapid spread emphasizes the need for accurate and fast diagnostic methods for large-scale screening. Here, we describe a robust method for the detection of pathogens based on microscale thermophoresis (MST). The method involves the hybridization of a fluorescently labeled DNA probe to a target RNA and the assessment of thermophoretic migration of the resulting complex in solution within a 2 to 30-time window. We found that the thermophoretic migration of the nucleic acid-based probes is primarily determined by the fluorescent molecule used, rather than the nucleic acid sequence of the probe. Furthermore, a panel of uniformly labeled probes that bind to the same target RNA yields a more responsive detection pattern than a single probe, and moreover, can be used for the detection of specific pathogen variants. In addition, intercalating agents (ICA) can be used to alter migration directionality to improve detection sensitivity and resolving power by several orders of magnitude. We show that this approach can rapidly diagnose viral SARS-CoV2, influenza H1N1, artificial pathogen targets, and bacterial infections. Furthermore, it can be used for anti-microbial resistance testing within 2 h, demonstrating its diagnostic potential for early pathogen detection.

Hunting for mpox (monkeypox) mimickers: Use of the Biofire meningitis/encephalitis panel on lesion swabs to support alternative viral diagnoses

BACKGROUND

Mpox (formerly monkeypox) is an emerging zoonotic disease of public health concern that presents as a rash mimicking other common viral exanthems. Unlike traditional testing algorithms relying on several assays, the BioFire FilmArray meningitis/encephalitis (ME) panel simultaneously detects common viruses causing rashes; however, Biofire ME is only licensed for testing on cerebral spinal fluid.

OBJECTIVES

This study evaluated use of the Biofire ME panel for detection and discrimination of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), human herpesviruses type 6 (HHV-6), enteroviruses (EVs), and human paraechoviruses (HPeVs) from a dermal or mucocutaneous swabs collected in universal transport media (UTM).

STUDY DESIGN

Results of the BioFire ME panel were compared against methods used during clinical testing. Ten-fold serial dilutions in UTM of cultured viruses were used to compare analytical sensitivity, and analytical specificity was assessed using panels of microorganisms in UTM. Clinical sensitivity and specificity were assessed using 20 positive specimens each for HHV-1, HHV-2, HHV-6, VZV, EVs, and HPeV, as well as 35 known negative specimens that included 15 mpox-positive specimens.

RESULTS

Biofire ME was as sensitive as comparator methods, and correctly discriminated all HSV-1, HSV-2, VZV, HHV-6, EVs, and HPeVs from mpox and mpox-mimickers. Cross-reaction between EV and rhinoviruses A, B, and C were noted in the specificity panel.

CONCLUSIONS

Swabs in UTM collected for mpox testing are suitable for use on the Biofire ME panel, allowing more streamlined diagnostic testing for viral exanthems in patients under investigation for mpox infection.

Molecular diagnosis of Trichomonas vaginalis in liquid-based Papanicolaou samples in Shiraz, southern Iran

BACKGROUND

Trichomoniasis is a parasitic infection of the urinary and genital tract, caused by Trichomonas vaginalis. This study aimed to investigate the molecular diagnosis of T. vaginalis infection in liquid-based Papanicolaou samples in Shiraz, southern Iran.

MATERIALS AND METHODS

In this cross-sectional study, 534 liquid-based Papanicolaou samples were collected from women referring to the laboratory of Motahari Clinic of Shiraz University of Medical Sciences in 2021. Genomic DNA were extracted from the samples and examined for evidence of T. vaginalis using polymerase chain reaction (PCR) using TVK3 and TVK7 specific primers.

RESULTS

The mean age of participants was 39.28 ± 9.89 with a maximum age of 65 and a minimum age of 19 years. T. vaginalis DNA fragments were detected in 4.86% (26/534) of the cases. There was significantly higher prevalence in the age groups of 21 to 30 and 41 to 50 years (46.15%, p = 0.001 and 38.46%, p = 0.015, respectively). Furthermore, the results showed an association between a history of foamy discharge and Trichomonas positivity (p = 0.001).

CONCLUSION

T. vaginalis infection is common in liquid-based Papanicolaou samples of women who attended regular health check-ups in the study area. Screening for trichomoniasis in populations, particularly if using highly sensitive methods such as PCR, may lead to increased detection and treatment.

Investigating the microbial pathogens of sexually transmitted infections among heterosexual Vietnamese men with symptomatic urethritis

OBJECTIVE

To explore the microbial etiology of urethritis in Vietnamese men and the association with patients' characteristics, especially their sexual behaviors.

METHODS

This study was conducted on 349 men who presented with symptomatic urethritis and evidence of STIs (determined by multiplex PCR tests) at the Department of Andrology and Sexual Medicine-Hanoi Medical University Hospital. All information regarding medical history, sexual activities, and symptoms of urethritis was documented.

RESULTS

C. trachomatis and N. gonorrhoea remained the two most common causative pathogens, followed by an unexpectedly high prevalence of Mycoplasma and Ureaplasma species. Coinfection was significant with a rate of 40.7%. Men who had sex with female sex workers (FSWs) were more likely to be positive with N. gonorrhoea but less likely to be positive with C. trachomatis and M. genitalium than those having sex with only one romantic partner.

CONCLUSIONS

Our findings suggested the important role of other microorganisms, especially M. genitalium, in the etiology of urethritis in men besides the previously well-known causes of STIs. Since the coinfection rate is quite high, targeted treatment with clear microbial evidence should be considered rather than empiric antimicrobial therapy.

Molecular Epidemiology of Genital Infections in Campania Region: A Retrospective Study

This study provides updated information on the prevalence and co-infections caused by genital microorganisms and pathogens: Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, Ureaplasma urealyticum, Trichomonas vaginalis, and Gardnerella vaginalis, by retrospectively analyzing a cohort of patients living in the Naples metropolitan area, Campania region, Southern Italy. To investigate the genital infections prevalence in clinical specimens (vaginal/endocervical swabs and urines) collected from infertile asymptomatic women and men from November 2018 to December 2020, we used a multiplex real-time PCR assay. Of the 717 specimens collected, 302 (42.1%) resulted positive for at least one of the targets named above. Statistically significant differences in genital prevalence of selected microorganisms were detected in both women (62.91%) and men (37.08%). G. vaginalis and U. parvum represented the most common findings with an 80.2% and 16.9% prevalence in vaginal/endocervical swabs and first-voided urines, respectively. Prevalence of multiple infections was 18.18% and 8.19% in women and men, respectively. The most frequent association detected was the co-infection of G. vaginalis and U. parvum with 60% prevalence. Our epidemiological analysis suggests different infection patterns between genders, highlighting the need to implement a preventative screening strategy of genital infections to reduce the complications on reproductive organs.

Bridging the gap between development of point-of-care nucleic acid testing and patient care for sexually transmitted infections

The incidence rates of sexually transmitted infections (STIs), including the four major curable STIs - chlamydia, gonorrhea, trichomoniasis and, syphilis - continue to increase globally, causing medical cost burden and morbidity especially in low and middle-income countries (LMIC). There have seen significant advances in diagnostic testing, but commercial antigen-based point-of-care tests (POCTs) are often insufficiently sensitive and specific, while near-point-of-care (POC) instruments that can perform sensitive and specific nucleic acid amplification tests (NAATs) are technically complex and expensive, especially for LMIC. Thus, there remains a critical need for NAAT-based STI POCTs that can improve diagnosis and curb the ongoing epidemic. Unfortunately, the development of such POCTs has been challenging due to the gap between researchers developing new technologies and healthcare providers using these technologies. This review aims to bridge this gap. We first present a short introduction of the four major STIs, followed by a discussion on the current landscape of commercial near-POC instruments for the detection of these STIs. We present relevant research toward addressing the gaps in developing NAAT-based STI POCT technologies and supplement this discussion with technologies for HIV and other infectious diseases, which may be adapted for STIs. Additionally, as case studies, we highlight the developmental trajectory of two different POCT technologies, including one approved by the United States Food and Drug Administration (FDA). Finally, we offer our perspectives on future development of NAAT-based STI POCT technologies.

Characteristics of Vaginal Microbiome in Women with Pelvic Inflammatory Disease in Korea

Human vaginal microorganisms play an important role in maintaining good health throughout the human life cycle. An imbalance in the vaginal microbiota is associated with an increased risk of pelvic inflammatory disease (PID). This study aimed to characterize and compare vaginal microbial profiles of premenopausal Korean women with and without PID. 74 Korean premenopausal female vaginal samples were obtained; 33 were from healthy women (a control group) and 41 from PID patients. Vaginal fluid samples were collected from the vaginal wall and posterior cervix and then analyzed by 16S ribosomal ribonucleic acid (rRNA) gene-based amplicon sequencing. Results showed a significant difference between the vaginal microbial communities of the two groups (Jensen-Shannon, p = 0.014; Bray-Curtis, p = 0.009; Generalized UniFrac, p = 0.007; UniFrac, p = 0.008). Lactobacillus accounted for the highest percentage (61.0%) of the control group but was significantly decreased (34.9%) in PID patients; this was the most significant difference among all bacterial communities (p = 0.028, LDA effect size = 5.129). In addition, in the PID patient group, species diversity significantly increased (Simpson, p = 0.07) as the proportion of various pathogens increased evenly, resulting in a polymicrobial infection. Similarly, lactate, which constituted the highest percentage of the organic acids in the control group, was significantly decreased in the PID patient group (p = 0.04). The present study's findings will help understand PID from the microbiome perspective and are expected to contribute to the development of more efficient PID diagnosis and treatment modalities.

Testing as Prevention of Resistance in Bacteria Causing Sexually Transmitted Infections-A Population-Based Model for Germany

Prescribed antibiotic treatments which do not match the therapeutic requirements of potentially co-existing undetected sexually transmitted infections (STIs) can facilitate the selection of antibiotic-drug-resistant clones. To reduce this risk, this modelling assessed the potential applicability of reliable rapid molecular test assays targeting bacterial STI prior to the prescription of antibiotic drugs. The modelling was based on the prevalence of three bacterial STIs in German heterosexual and men-having-sex-with-men (MSM) populations, as well as on reported test characteristics of respective assays. In the case of the application of rapid molecular STI assays for screening, the numbers needed to test in order to correctly identify any of the included bacterial STIs ranged from 103 to 104 for the heterosexual population and from 5 to 14 for the MSM population. The number needed to harm—defined as getting a false negative result for any of the STIs and a false positive signal for another one, potentially leading to an even more inappropriate adaptation of antibiotic therapy than without any STI screening—was at least 208,995 for the heterosexuals and 16,977 for the MSM. Therefore, the screening approach may indeed be suitable to avoid unnecessary selective pressure on bacterial causes of sexually transmitted infections.

Current and Future Trends in the Laboratory Diagnosis of Sexually Transmitted Infections

Sexually transmitted infections (STIs) continue to exert a considerable public health and social burden globally, particularly for developing countries. Due to the high prevalence of asymptomatic infections and the limitations of symptom-based (syndromic) diagnosis, confirmation of infection using laboratory tools is essential to choose the most appropriate course of treatment and to screen at-risk groups. Numerous laboratory tests and platforms have been developed for gonorrhea, chlamydia, syphilis, trichomoniasis, genital mycoplasmas, herpesviruses, and human papillomavirus. Point-of-care testing is now a possibility, and microfluidic and high-throughput omics technologies promise to revolutionize the diagnosis of STIs. The scope of this paper is to provide an updated overview of the current laboratory diagnostic tools for these infections, highlighting their advantages, limitations, and point-of-care adaptability. The diagnostic applicability of the latest molecular and biochemical approaches is also discussed.

Use of a Multiplex PCR Assay To Assess the Presence of Treponema pallidum in Mucocutaneous Ulcerations in Patients with Suspected Syphilis

We evaluated the utility of the commercial Allplex genital ulcer real-time PCR multiplex assay for detecting Treponema pallidum, herpes simplex virus 1 (HSV-1) and 2 (HSV-2), and Chlamydia trachomatis serovar L (lymphogranuloma venereum [LGV]) DNA in mucosal and genital ulcers in the context of suspected syphilis. In total, 374 documented genital and mucosal ulcers from patients with and without syphilis presenting at several sexually transmitted infection (STI) centers in France from October 2010 to December 2016 were analyzed at the National Reference Center (CNR) for Bacterial STIs at Cochin Hospital in Paris. T. pallidum subsp. pallidum detection results were compared with the final diagnosis based on a combination of clinical examination, serological results, and in-house nested PCR (nPCR). Detections of HSV and LGV were validated against reference methods. We found that 44.6% of the 374 samples tested were positive for T. pallidum subsp. pallidum, 21% for HSV, and 0.8% for LGV. No positive results were obtained for 30.7% of samples, and 4.8% presented coinfections. For T. pallidum subsp. pallidum detection, the overall sensitivity was 80% (95% confidence interval [CI], 76.1 to 84.1%), specificity was 98.8% (95% CI, 97.7 to 99.9%), positive predictive value was 98.8% (95% CI, 97.7 to 99.9%) and negative predictive value was 80.2% (95% CI, 76.2 to 84.2%), with a rate of concordance with the reference method of 92.5% (k = 0.85). This PCR multiplex assay is suitable for T. pallidum subsp. pallidum detection in routine use and facilitates the simultaneous rapid detection of a broad panel of pathogens relevant in a context of suspected syphilis lesions.

Laboratory Perspective on Racial Disparities in Sexually Transmitted Infections

BACKGROUND

Rates of sexually transmitted infections (STI) have risen steadily in recent years, and racial and ethnic minorities have borne the disproportionate burden of STI increases in the United States. Historical inequities and social determinants of health are significant contributors to observed disparities and affect access to diagnostic testing for STI.

CONTENT

Public health systems rely heavily on laboratory medicine professionals for diagnosis and reporting of STI. Therefore, it is imperative that clinicians and laboratory professionals be familiar with issues underlying disparities in STI incidence and barriers to reliable diagnostic testing. In this mini-review, we will summarize contributors to racial/ethnic disparity in STI, highlight current epidemiologic trends for gonorrhea, chlamydia, and syphilis, discuss policy issues that affect laboratory and public health funding, and identify specific analytic challenges for diagnostic laboratories.

SUMMARY

Racial and ethnic disparities in STI in the US are striking and are due to complex interactions of myriad social determinants of health. Budgetary cuts for laboratory and public health services and competition for resources during the COVID-19 pandemic are major challenges. Laboratory professionals must be aware of these underlying issues and work to maximize efforts to ensure equitable access to diagnostic STI testing for all persons, particularly those most disproportionately burdened by STI.

Male urethritis. A review of the ideal diagnostic method

Male urethritis is an inflammation of the urethra and the periurethral glands; it is widely classified as gonococcal or non-gonococcal. The most frequent microorganisms responsible are Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum. In the last three decades, the diagnosis of sexually transmitted diseases depended almost exclusively on traditional methods, such as culture, enzyme immunoassay, fluorescent antibody staining, and hybridization, until the appearance of molecular techniques. Clinical syndromes such as urethritis are rarely specific for a single microorganism, so screening strategies should allow multiple agents to be considered. Multiplex PCR is the fastest and most sensitive technique for the diagnosis of gonococcal and non-gonococcal urethritis. Male urethritis without treatment is one of the main health problems related to reproductive and sexual function, constituting one of the main causes of infertility. The objective of this mini-review was to analyze the epidemiology, causes, diagnosis, and complications of male urethritis.

All-in-one microfluidic nucleic acid diagnosis system for multiplex detection of sexually transmitted pathogens directly from genitourinary secretions

Sexually transmitted infections are a serious public health concern worldwide, especially in young people. More than 30 pathogens can cause sexually transmitted diseases and co-infection often occurs. Therefore, the development of fast, low-cost and easy-to-use diagnostic screening methods is urgently needed for disease prevention and control. Herein, we established an all-in-one microfluidic nucleic acid diagnosis system, which could simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum directly from genitourinary secretions with minimal manual manipulations. This system integrated nucleic acid extraction, amplification, and detection on a single microfluidic chip and could be automatically performed in an integrated detection device. This novel diagnosis tool showed good detection limits, stability (coefficient of variation <6%), specificity (no cross-reaction with 23 other pathogens for each target) and resistance to interference by other substances and the diagnostic efficacy was similar to that of PCR. The turn-around time was reduced to 50 min from sample to answer with automated testing steps. This novel diagnosis tool has the advantages of highly integrated, automated, sample-to-answer detection, and could thus replace the traditional method. This could significantly improve the prevention and control of sexually transmitted diseases.

Cervical Cytology of Samples with Ureaplasma urealyticum, Ureaplasma parvum, Chlamydia trachomatis, Trichomonas vaginalis, Mycoplasma hominis, and Neisseria gonorrhoeae Detected by Multiplex PCR

Introduction

Despite increasing application of molecular diagnostic methods for the detection of sexually transmitted infections, the cytological findings in pap smears of patients with pathogens that can be identified only by PCR are not yet well described. The aim of this study was to describe the most common cytological features in cervical pap smears of patients with Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum detected by multiplex PCR.

Methods

Cervical samples for conventional and liquid-based cytology and for multiplex PCR were collected from women ranging from 23 to 54 years old, who underwent routine screening at a gynecological Unit.

Results

Multiplex PCR was positive in 36.2% of the samples: Ureaplasma parvum 14.9%, Chlamydia trachomatis 10.6%, Trichomonas vaginalis 10.6%, Mycoplasma hominis 8.5%, Ureaplasma urealyticum 4.2%, Neisseria gonorrhoeae 2.1%, and Mycoplasma genitalium (0). Multiple pathogens were observed in 12.8% of samples. Microscopic cervicitis (≥10 polymorphonuclear leukocytes/epithelial cell) and normal (predominantly lactobacillary) microbiota were the most frequent findings in the samples in which the pathogens were detected alone or in multiple infections, except for samples with Trichomonas vaginalis in which the coccobacillary microbiota was the most common. In samples with microscopic cervicitis and normal microbiota, those with at least one pathogen identified by multiplex PCR were significantly more frequent than those with no pathogen, 66.6% versus 33.3%.

Conclusion

Failure to identify an inflammatory agent in pap smear with intense neutrophil exudate may suggest the presence of Ureaplasma parvum, Ureaplasma urealyticum, Chlamydia trachomatis, or Trichomonas vaginalis. A remark on the intensity of inflammation should be made in the reports of cervical pap smears so that this cytological finding can be correlated with clinical and PCR results.

Prevalence of Mycoplasma genitalium by anatomical site in men who have sex with men: a systematic review and meta-analysis

OBJECTIVE

To systematically review and appraise published data, to determine the prevalence of Mycoplasma genitalium (MG) in men who have sex with men (MSM) tested at each anatomical site, that is, at the urethra, rectum and/or pharynx.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Ovid Medline, PubMed, Embase were searched for articles from 1st January 1981 (the year MG was first identified) to 1st June 2018.

REVIEW METHODS

Studies were eligible for inclusion if they reported MG prevalence in MSM tested at the urethra, rectum and/or pharynx, in at least 50 MSM, using nucleic acid amplification testing. Data were extracted by anatomical site, symptom and HIV status. Summary estimates (95% CIs) were calculated using random-effects meta-analysis. Subgroup analyses were performed to assess heterogeneity between studies.

RESULTS

Forty-six studies met inclusion criteria, with 34 reporting estimates of MG prevalence at the urethra (13 753 samples), 25 at the rectum (8629 samples) and 7 at the pharynx (1871 samples). MG prevalence was 5.0% (95% CI 3.5 to 6.8; I²=94.0) at the urethra; 6.2% (95% CI 4.6 to 8.1; I²=88.1) at the rectum and 1.0% (95% CI 0.0 to 5.1; I²=96.0) at the pharynx. The prevalence of MG was significantly higher at urethral and rectal sites in symptomatic versus asymptomatic MSM (7.1% vs 2.2%, p<0.001; and 16.1% vs 7.5%, p=0.039, respectively). MG prevalence at the urethra was significantly higher in HIV-positive compared with HIV-negative MSM (7.0% vs 3.4%, p=0.006).

CONCLUSION

MG was common in MSM, particularly at urethral and rectal sites (5% to 6%). MG was more commonly detected in symptomatic men at both sites, and more common in HIV-positive men at the urethra. MG was uncommonly detected in the pharynx. Site-specific estimates are similar to those for chlamydia and will be helpful in informing testing practices in MSM.

PROSPERO REGISTRATION NUMBER

CRD42017058326.

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.

Gonorrhoea: past, present and future

The sexually transmitted infection (STI) gonorrhoea is an ancient human disease caused by the Gram-negative bacterial pathogen Neisseria gonorrhoeae. Despite decades of research focused on preventing, diagnosing, and treating gonorrhoea, it remains a major global health concern due to its high prevalence, high rates of asymptomatic cases, the severe sequelae that can result from untreated infections, and the increasing difficulty in treating infections caused by multi-drug resistant strains of N. gonorrhoeae. It is estimated that there are more than 87 million cases of gonorrhoea worldwide each year, and the WHO, CDC and Australian National Antimicrobial Resistance (AMR) Strategy have prioritised N. gonorrhoeae as an urgent public health threat for which new therapeutics and a vaccine are needed.

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.

PCR detection for syphilis diagnosis: Status and prospects

Syphilis, a re‐emerging public health problem worldwide caused by Treponema pallidum subsp pallidum (T. pallidum), usually induces systemic and chronic inflammation in hosts who do not receive timely therapy after exposing to high‐risk factors such as leprous sexual contact. Before the treatment, rapid and accurate detection of syphilis is essential. However, the existing detection methods, which focus on the treponemal or non‐treponemal antibody test, both have inherent limitations. For instance, both of them cannot distinguish the stage and severity of syphilis. Non‐treponemal test such as RPR, which is generally deemed to be used for assessing treatment response, is influenced by biological false positives. Therefore, it is imperative to seek out a new and effective diagnostic test. With recent advancements in molecular biology and whole‐genome sequencing, the molecular diagnosis has increased in popularity, especially the use of polymerase chain reaction (PCR). Here, we firstly present a mini‐review on the research of PCR detection methods used for syphilis diagnosis over the past decade, and we then compare these methodologies to assess their potential and the challenges faced. This information can provide a fresh perspective to help researchers address the current challenges.

Prospective evaluation study on the benefit of the simultaneous detection of seven sexually transmitted pathogens for the clinical management of patients suffering from sexually transmitted diseases

Background

Sexually transmitted infections (STIs) represent a growing relevant public health problem. Early and accurate STI diagnosis is capable of preventing the spread and severe complications of curable STIs through pathogen adapted antibiotic treatment regimens. Limitations of current STI diagnostic tools are the lack of simultaneous pathogen detection and result quantification.

Methods

A prospective analysis of clinical specimens (n=100, from 82 symptomatic patients) from different sites of infections was performed. All samples were processed with multiplex real-time polymerase chain reaction (PCR) assay Anyplex™ II STI-7, using thermal cycler CFX96™. The Anyplex™ II STI-7 detection assay covers Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), Mycoplasma hominis (MH), Ureaplasma parvum (UP), Ureaplasma urealyticum (UU) and Trichomonas vaginalis (TV). STI-7 results were compared to standard methods and transferred to the attending physician for treatment adjustment.

Results

Compared to performed standard method results the assay achieved sensitivities ranging from 90.9% to 100%, respectively, and specificities of 100%, with negative predictive values (NPV) ranging from 98.5% to 100%, respectively, and positive predictive values (PPV) of 100%. The Anyplex™ II STI-7 detection assay measured a Cohen’s kappa of 1.00 for UU/UP, MH, and MG and a Cohen’s κ agreement of 0.95 and 0.96 for NG and CT, respectively.

Conclusions

The Anyplex™ II STI-7 assay can easily be introduced into the microbiological laboratory work flow due to its short hands-on-time and PCR mutiplexity. The simultaneous detection of seven STI pathogens provides a comprehensive profile for each patient, enabling clinicians to decide on best treatment options, decreasing antibiotic misuse and infection spreading risk. The semi-quantitative results enables clinicians to gain a complete package of diagnostic information including disease diagnosis, disease degree severity and treatment monitoring, although. Further clinical studies on this topic are needed.

PCR-based rapid diagnostic tests as a strategy for preventing infections with sexually transmitted diseases-a 'diagnostics-as-prevention' modelling approach

The potential was modelled of molecular rapid diagnostic tests (RDTs) that target agents of sexually transmitted diseases (STDs) to contribute to a reduction in the exposure risk for sexually active populations who prefer condom-free high-risk contacts. The biostatistical approach is exemplified by considering the use of a PCR-based RDT for Chlamydia trachomatis and Neisseria gonorrhoeae in a population of German men having sex with men. We modelled the exposure risk as risk of sexual contact with individuals infected by a STD in spite of multiple RDTs having been conducted to identify STDs that could lead to avoidance of an infectious sexual contact. The risk for a given specific disease is influenced by the diagnostic accuracy of all diagnostic tests conducted. The simulation showed a reduction in exposure risk through conducting the selected PCR-based RDT as a strategy to prevent infections with C. trachomatis and N. gonorrhoeae in comparison with unprotected sexual contact of >97% for C. trachomatis and ≥96% for N. gonorrhoeae. Reliable knowledge of the performance characteristics of the diagnostic tests applied is essential for a thorough risk assessment based on such diagnostic approaches.

SIGNIFICANCE AND IMPACT OF THE STUDY

A low-threshold use of molecular rapid diagnostic tests in settings where risky sexual activity is undertaken with deliberate non-use of condoms is modelled. Such an approach might contribute to a considerable reduction in the exposure risk if positively tested individuals are excluded from unprotected sexual intercourse. Protective effects are influenced by the prevalence of the disease and the performance characteristics of the applied tests. Precise knowledge of the performance characteristics of the test assays employed are prerequisites of a reliable risk assessment. The modelling approach is of particular use for preventive health experts.

Oligonucleotide Microchip for the Identification of Infectious Agents of Reproductive System with Simultaneous Analysis of Determinants of Resistance to Antimicrobial Substances

We developed a multiplexed DNA microarray-based assay allowing identification of 12 causative agents of reproductive tract infections with the simultaneous detection of 47 genetic determinants of resistance to antimicrobial substances. The microarray was tested on 93 isolates of Neisseria gonorrhoeae, 32 isolates of Treponema pallidum and 29 samples of Ureaplasma spp./Mycoplasma spp. The N. gonorrhoeae isolates had multiple mutations in the penA, ponA, rpsJ, gyrA, parC, and mtrR genes; their prognostic value significantly increased when combinations of mutations were detected. In the analyzed T. pallidum isolates, single A2058G substitution in the 23S rRNA gene responsible for macrolide resistance was found. DNA sequences of Ureaplasma spp./Mycoplasma spp. were determined as wild type, which was not fully consistent with the results of analysis of their antimicrobial susceptibility.

[Nonviral sexually transmitted infections-epidemiology, clinical manifestations, diagnostic workup, therapy : Part 3: Treponemes, Gardnerella and trichomonads]

In Germany, the reported syphilis prevalence has increased continuously since 2010, with a total of 6834 syphilis cases being reported in 2015. The largest increase of reported syphilis occurred in men who have sex with men (MSM). The antibiotic agent of choice for treatment of syphilis is still penicillin. There are no penicillin-resistant Treponema pallidum strains. Alternatives are ceftriaxone and doxycycline. In Germany, azithromycin is not approved for treatment of syphilis; however, therapy failures are increasingly reported. Bacterial vaginosis is accompanied by vaginal discharge. The vaginal secretion exhibits an increased pH value higher than 4.5. Clinical symptoms are pruritus, burning, and the characteristic amine odor. The probability for bacterial vaginosis is highest in women with higher numbers of sexual partners, unmarried women, early first sexual intercourse, in commercial female sex workers, and those women who regularly apply vaginal douches. The main pathogen of bacterial vaginosis is Gardnerella vaginalis. For oral therapy metronidazole is given, alternatively clindamycin; the latter should be applied additionally as topical agent. Trichomoniasis is considered as the nonviral sexually transmitted infection with the highest prevalence worldwide. Other than direct microscopic detection of the protozoa (trophozoites) in vaginal secretion or urine, PCR has been approved as the diagnostic method with the highest sensitivity. Oral metronidazole represents the therapy of choice in trichomoniasis.

[Non-viral sexually transmitted infections - Epidemiology, clinical manifestations, diagnostics and therapy : Part 2: Chlamydia and mycoplasma]

Chlamydia trachomatis is the most common pathogen of sexually transmitted bacterial infections worldwide. Every year in Germany approximately 300,000 new infections are to be expected. Chlamydia infections occur nearly exclusively in the postpubertal period. The peak age group is 15-25 years. The infection usually runs an asymptomatic course and the diagnosis is made by nucleic acid amplification techniques (NAAT) often after chlamydial screening or if complications occur. For treatment of chlamydial infections oral doxycycline 100 mg twice daily over 7 days is initially used or alternatively oral azithromycin 1.5 g as a single dose is recommended. The sexual partner should also be investigated and treated. Genital Mycoplasma infections are caused by Ureaplasma urealyticum (pathogen of urethritis and vaginitis), Ureaplasma parvum (mostly saprophytic and rarely a cause of urethritis) and Mycoplasma hominis (facultative pathogenic). Mycoplasma genitalium represents a relatively new sexually transmitted Mycoplasma species. Doxycycline is effective in Ureaplasma infections or alternatively clarithromycin and azithromycin. Doxycycline can be ineffective in Mycoplasma hominis infections and an alternative is clindamycin. Non-gonococcal and non-chlamydial urethritis due to Mycoplasma genitalium can now be diagnosed by molecular biological techniques using PCR and should be treated by azithromycin.

Molecular Diagnostics Update for the Emerging (If Not Already Widespread) Sexually Transmitted Infection Agent Mycoplasma genitalium: Just About Ready for Prime Time

Mycoplasma genitalium is an important and emerging agent of sexually transmitted infection in females and males, carrying the potential for postinfection genital tract sequelae. Past efforts to identify this organism on a routine basis, which were problematic due to the fastidious nature of the bacterium and its antigenic intricacies, have recently become supplemented by molecular diagnostics. A number of these assays are available commercially. This minireview describes the format and performance indices of a number of M. genitalium DNA- and RNA-based amplification assays; many of these assays have contributed to an improved clinical and epidemiologic understanding of this organism.

Rapid diagnosis of sexually transmitted infections

Sexually transmitted infections (STIs) are responsible for an enormous burden of morbidity and mortality. Worldwide, millions of cases of STIs, such as syphilis, chlamydia, or gonorrhoea occur every year, and there is now an increase in antimicrobial resistance in pathogens, such as gonococcus. Delay in diagnosis is one of the factors that justifies the difficulty in controlling these infections. Rapid diagnostic tests allow the introduction of aetiological treatment at the first visit, and also leads to treating symptomatic and asymptomatic patients more effectively, as well as to interrupt the epidemiological transmission chain without delay. The World Health Organisation includes these tests in its global strategy against STIs.

Spatial distribution and cluster analysis of risky sexual behaviours and STDs reported by Chinese adults in Guangzhou, China: a representative population-based study

OBJECTIVES

To assess associations between residences location, risky sexual behaviours and sexually transmitted diseases (STDs) among adults living in Guangzhou, China.

METHODS

Data were obtained from 751 Chinese adults aged 18-59 years in Guangzhou, China, using stratified random sampling by using spatial epidemiological methods. Face-to-face household interviews were conducted to collect self-report data on risky sexual behaviours and diagnosed STDs. Kulldorff's spatial scan statistic was implemented to identify and detect spatial distribution and clusters of risky sexual behaviours and STDs. The presence and location of statistically significant clusters were mapped in the study areas using ArcGIS software.

RESULTS

The prevalence of self-reported risky sexual behaviours was between 5.1% and 50.0%. The self-reported lifetime prevalence of diagnosed STDs was 7.06%. Anal intercourse clustered in an area located along the border within the rural-urban continuum (p=0.001). High rate clusters for alcohol or other drugs using before sex (p=0.008) and migrants who lived in Guangzhou <1 year (p=0.007) overlapped this cluster. Excess cases for unprotected sex (p=0.031) overlapped the cluster for college students (p<0.001). Five of nine (55.6%) students who had sexual experience during the last 12 months located in the cluster of unprotected sex.

CONCLUSIONS

Short-term migrants and college students reported greater risky sexual behaviours. Programmes to increase safer sex within these communities to reduce the risk of STDs are warranted in Guangzhou. Spatial analysis identified geographical clusters of risky sexual behaviours, which is critical for optimising surveillance and targeting control measures for these locations in the future.