The laboratory diagnosis of Neisseria gonorrhoeae

Molecular docking and ADMET studies of halogenated metabolites from marine sponges as inhibitors of wild-type and mutants PBP2 in Neisseria gonorrhoeae

Gonorrhoea is a sexually transmitted infection (STI) caused by the bacteria Neisseria gonorrhoeae. Gonorrhoea symptoms can vary, although roughly 50% of women and 10% of men infected with N. gonorrhoeae may be asymptomatic. If left untreated, gonorrhoea can cause major health problems. However, no effective treatment or vaccination is currently available. The enzyme penicillin-binding protein 2 (PBP2) is necessary for cell wall synthesis during N. gonorrhoeae cell growth. The goal of this study is to investigate the molecular interactions of three PBP2 variants with halogenated marine sponge metabolites using molecular docking, molecular dynamic simulation, and ADMET analysis. The docking findings were evaluated using the glide gscore, and the top 20 compounds docked against each PBP2 protein receptor were chosen. Furthermore, the selected compounds underwent ADMET analysis, indicating that they have the potential for therapeutic development. Among the selected compounds, Bromoageliferin had the highest affinity for PBP2, Psammaplysin E for the penicillin-resistant variation of PBP2 protein, and Preaxinellamine for the cephalosporin-resistant variant of PBP2 protein. Additionally, MM-GBSA binding free energy and molecular dynamics simulations were used to support the docking investigations. The results of the study suggest that these compounds may eventually be used to treat gonorrhoea. However, computer validations were included in this study, and more in-vitro research is required to turn these prospective inhibitors into clinical drugs.Communicated by Ramaswamy H. Sarma.

Exploiting β-Lactams-Induced Lysis and DNA Fragmentation for Rapid Molecular Antimicrobial Susceptibility Testing of Neisseria Gonorrhoeae via Dual-Digital PCR

The evolution of antimicrobial resistance (AMR) presents substantial challenges to global medical health systems. Neisseria gonorrhoeae (N. gonorrhoeae), in particular, has developed resistance to all currently available antimicrobials. Addressing this issue necessitates not only discovering new antimicrobials but also deepening the understanding of bacterial responses to these agents, which can lead to new markers for rapid antimicrobial susceptibility testing (AST). Such advancements can enhance treatment outcomes and promote antimicrobial stewardship. In this study, single-cell techniques, including live-cell imaging, flow cytometry, and digital polymerase chain reaction (PCR) are utilized, to investigate the lysis dynamics and molecular features of N. gonorrhoeae upon exposure to β-lactam antimicrobials. Distinct patterns of bacterial lysis and DNA fragmentation are uncovered in susceptible strains. Leveraging these discoveries, a microfluidic dual-digital PCR approach that combines single-cell and single-molecule analyses, facilitate rapid and efficient phenotypic molecular AST for N. gonorrhoeae against β-lactams is developed. This proof-of-concept validation demonstrates the effectiveness of the method in accessing antimicrobial susceptibility across a range of bacterial strains, contributing valuable insights for advancing the battle against AMR.

Prevalence of gonococcal and chlamydial infections among men who have sex with men in sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Men who have sex with men (MSM) are disproportionately affected by sexually transmitted infections (STI) including Neisseria gonorrhoeae (Ng) and Chlamydia trachomatis (Ct). The lack of robust data on STIs among African MSM has limited the development of evidence-based screening strategies. This study aimed at documenting the pooled prevalence of Ng/Ct among MSM in sub-Saharan Africa (SSA).

METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) 2020 guidelines. Relevant articles from the following databases were searched: PubMed, Scopus, ISI Web of Science, and the Directory of Open Access Journals (DOAJ). Eligible studies reported on the prevalence of Ng/Ct among the MSM population in SSA. Publication bias was assessed using the Hoy tool, Doi plot, and LFK ratio. Due to heterogeneity among studies, subgroup analyses were performed using the MetaXL add-on tool for Microsoft Excel.

RESULTS

Of 525 articles screened, 20 were selected for inclusion. Six were cross-sectional, four had a prospective cohort study design, and one was an epidemiological study. The pooled prevalence of Ng/Ct in MSM was 27% (95% CI, 19-39%), with an I2 of 98% signifying heterogeneity among the studies. Subgroup analysis by country revealed South Africa had the highest prevalence (38%).

DISCUSSION

Interpretation The high prevalence of Ng/Ct infection among MSM in SSA is of concern. Limitations Due to limited data available on Ng/Ct prevalence, the true prevalence of SSA and its associated risk factors is uncertain.

CONCLUSION

As the first study to systematically review the available literature on STI prevalence among the MSM population in SSA, it showed the burden of Ng/Ct is higher than in other regions, warranting the strengthening of health systems to improve education, testing, and treatment in MSM population.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022327095.

Limitations of current techniques in clinical antimicrobial resistance diagnosis: examples and future prospects

Antimicrobial resistance is a global threat to public health. Without proactive intervention, common infections may become untreatable, restricting the types of clinical intervention that can be undertaken and reversing improvements in mortality rates. Effective antimicrobial stewardship represents one approach to restrict the spread of antimicrobial resistance but relies on rapid and accurate diagnostics that minimise the unnecessary use of antibiotics. This is increasingly a key unmet clinical need. In this paper, we describe existing techniques for the detection of antimicrobial resistance, while examining their drawbacks and limitations. We also discuss emerging diagnostic technologies in the field, and the need for standardisation to allow for swifter and more widespread clinical adoption.

Improving gonorrhoea molecular diagnostics: Genome mining-based identification of identical multi-repeat sequences (IMRS) in Neisseria gonorrhoeae

Background

Curable sexually transmitted infections (STIs), such as Neisseria gonorrhoeae (N. gonorrhoeae), are a major cause of poor pregnancy outcomes. The infection is often asymptomatic in pregnant women, and a syndrome-based approach of testing leads to a missed diagnosis. Culture followed by microscopy is inadequate and time-consuming. The gold standard nucleic acid amplification tests require advanced infrastructure settings, whereas point-of-care tests are limited to immunoassays with sensitivities and specificities insufficient to accurately diagnose asymptomatic cases. This necessitates the development and validation of assays that are fit for purpose.

Methods

We identified new diagnostic target biomarker regions for N. gonorrhoeae using an algorithm for genome mining of identical multi-repeat sequences (IMRS). These were then developed as DNA amplification primers to design better diagnostic assays. To test the primer pair, genomic DNA was 10-fold serially diluted (100 pg/μL to 1 × 10-3 pg/μL) and used as DNA template for PCR reactions. The gold standard PCR using 16S rRNA primers was also run as a comparative test, and both assay products were resolved on 1% agarose gel.

Results

Our newly developed N. gonorrhoeae IMRS-PCR assay had an analytical sensitivity of 6 fg/μL representing better sensitivity than the 16S rRNA PCR assay with an analytical sensitivity of 4.3096 pg/μL. The assay was also successfully validated using clinical urethral swab samples. We further advanced this technique by developing an isothermal IMRS, which was both reliable and sensitive for detecting cultured N. gonorrhoeae isolates at a concentration of 38 ng/μL. Combining isothermal IMRS with a low-cost lateral flow assay, we were able to detect N. gonorrhoeae amplicons at a starting concentration of 100 pg/μL.

Conclusion

Therefore, there is a potential to implement this concept within miniaturized, isothermal, microfluidic platforms, and laboratory-on-a-chip diagnostic devices for highly reliable point-of-care testing.

In silico exploration of hypothetical proteins in Neisseria gonorrhoeae for identification of therapeutic targets

Neisseria gonorrhoeae, a World Health Organization (WHO) declared superbug and the second-most frequent cause of bacterial sexually transmitted infections worldwide is responsible for gonorrhea. Hypothetical proteins are gene products that are predicted to be encoded by a particular gene based on the DNA sequence, but their specific functions and characteristics have not been experimentally determined or verified. In the context of this research, annotating hypothetical proteins is crucial for identifying their potential as therapeutic targets. Without proper annotation, these proteins would remain vague, hindering efforts to understand their roles in disease. The methodology used aims to bridge this gap by employing algorithm-based tools and software to annotate hypothetical proteins and assess their suitability as therapeutic targets based on factors such as essentiality, virulence, subcellular localization, and druggability. Out of 716 N. gonorrhoeae hypothetical proteins reported in UniProt, assessment of crucial pathogenic factors, including essentiality, virulence, subcellular localization, and druggability, effectively filtered and prioritized the hypothetical proteins for further therapeutic exploration and lead to 5 proteins being chosen as targets. The molecular docking studies conducted identified 10 hits targeting the five targets. Conclusively, this study aided in identification of targets and hit compounds for therapeutic targeting of gonorrhea disease.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00186-w.

Neisseria gonorrhoeae antimicrobial resistance patterns and associated risk factors in women of childbearing potential in northwestern Ethiopia

BACKGROUNDS

Neisseria gonorrhoeae causes gonorrhea and poses public health problems, including antimicrobial resistance. Current data on gonorrhea in prenatal participants in the study area are required. Thus, we aimed to identify gonorrhea prevalence, antimicrobial resistance, and risk factors among antenatal care clinic visitors in northwestern Ethiopia.

METHODS

A cross-sectional study was conducted from March to August 2022 at the University of Gondar Comprehensive Specialized Hospital. We recruited 278 study participants using convenient sampling techniques. Sociodemographic, clinical and behavioral risk factors were recorded using pre-tested questionnaires. Endocervical swabs were collected by a physician, transported to the microbiology laboratory, immediately inoculated into modified Thayer-Martin medium, and it was incubated at 37 °C for 24-48 hours. Gram staining and biochemical tests were used to identify the organism. AMR testing was performed using disc diffusion and E-test methods. Data were entered in EPI-info version 7 and exported and analyzed in SPSS version 26. A p-value ≤0.05 was considered as statistically significant. Results were presented in words, tables and figure.

RESULTS

Of 278 subjects enrolled, majority (44.6%) were 26-35 years, with a mean age of 29.9 (SD = ±7.2) years, 69.4% were urban residents, and 70.5% were married. Twenty-one (7.6%) participants had gonorrhea. Overall antimicrobial resistance ranged from 19 to 100%. High resistant to tetracycline (100%) and penicillin (85.7%) were observed by both tests. Ciprofloxacin resistance was 52.4% by disc diffusion and 85.7% by E-test. By E-test, all isolates were sensitive to ceftriaxone, cefixime, azithromycin and spectinomycin; however, 7 (33.3%), 9 (42.9%), 9 (42.9%) and 5 (23.8%) isolates showed resistant to these antibiotics with disk method. Prevalence of beta-lactamase producing Neisseria gonorrhoeae was 85.7%. Alcohol consumption (p = 0.032), condom-free sexual practice (p = 0.010), multiple sexual partners (p < 0.001), pelvic pain (p = 0.018), and dysuria (p = 0.021) revealed increased risk of infection.

CONCLUSIONS

Compared with many previous studies in Ethiopia, we found high prevalence, antimicrobial resistance, and beta-lactamase-positive isolates. Multiple sexual partners, alcohol consumption, not using condom, pelvic pain and dysuria were predictors of this infection. Continuous large-scale monitoring of pathogen is essential for its prevention and control.

An amplification-free, 16S rRNA test for Neisseria gonorrhoeae in urine

An amplification-free, nanopore-based nucleic acid detection platform has been demonstrated for rapid, 16S rRNA sequence-specific detection of Neisseria gonorrhoeae at 10-100 CFU mL^-1 in human urine against background bacterial flora at 1000 CFU mL^-1. Gonorrhea is a very common notifiable communicable disease, antibiotic resistant strains have emerged, and the rate of reported gonococcal infections continues to increase. Since rapid clinical identification of bacterial pathogens in clinical samples is needed to guide proper antibiotic treatment and to control disease spread, it is important to engineer rapid, sensitive, selective, and inexpensive point-of-care (POC) diagnostic devices for pathogens such as N. gonorrhoeae. Our detector technology is based on straightforward conductometric detection of sustained blockage of a glass nanopore. Charge neutral, complementary peptide nucleic acid probes are conjugated to polystyrene beads to capture N. gonorrhoeae 16S rRNA selectively. In the presence of an electric field applied externally through a glass nanopore, the PNA-microbead conjugates that acquire substantial negative charge upon target hybridization are driven to the smaller diameter nanopore. At least partial blockage of the nanopore results in a sustained drop in ionic current that can be measured easily with simple electronics. The ability to detect N. gonorrhoeae over the range of 10 to 100 CFU mL^-1 spiked in human urine was demonstrated successfully with estimated sensitivity and specificity of ∼98% and ∼100%, respectively. No false positives were observed for the control group of representative background flora (E. coli, K. pneumoniae, and E. faecalis) at 1000 CFU mL^-1. Also, N. gonorrhoeae at 50 CFU mL^-1 was successfully detected against 1000 CFU mL^-1 of background flora in urine. These results suggest that this amplification-free technology may serve as the basis for rapid, inexpensive, low-power detection of pathogens in clinical samples at the POC.

Exploring the Molecular Pathogenesis, Pathogen Association, and Therapeutic Strategies against HPV Infection

The human papillomavirus (HPV), commonly documented as the cause of warts, has gained much interest recently due to its possible links to several types of cancer. HPV infection is discussed in this review from multiple angles, including its virology, epidemiology, etiology, immunology, clinical symptoms, and treatment. Recent breakthroughs in molecular biology have led to the development of new methods for detecting and treating HPV in tissue. There is no cure for HPV, and although vaccines are available to prevent infection with the most common HPV viruses, their utilization is limited. Destruction and excision are the primary treatment modalities. This review sheds light on the epidemiology, molecular pathogenesis, the association of several other pathogens with HPV, the latest treatment strategies available to treat the same, and an overview of the progress made and the obstacles still to be overcome in the fight against HPV infection.

Resistance profiles of Neisseria gonorrhoeae isolates in Vienna, Austria: a phenotypic and genetic characterization from 2013 to 2020

OBJECTIVES

International surveillance data show a constant rise in the number of Neisseria gonorrhoeae infections and an increase in drug resistance of N. gonorrhoeae. As recent N. gonorrhoeae surveillance data in Austria are scarce, this study investigated phenotypic and genotypic antimicrobial resistance in N. gonorrhoeae isolates.

METHODS

In total, 440 N. gonorrhoeae samples were collected at the Medical University of Vienna, and the minimal inhibitory concentrations (MICs) for a range of different antibiotics were determined. Sampling sites and treatments were recorded, and whole-genome sequencing of N. gonorrhoeae isolates was performed using allele libraries to determine genotypic resistance.

RESULTS

The median MICs for ceftriaxone, cefixime, azithromycin, ciprofloxacin, tetracycline and penicillin were <0.002 µg/mL, <0.016 µg/mL, 0.25 µg/mL, 2.0 µg/mL, 1.5 µg/mL and 0.25 µg/mL, respectively. Annual comparison showed that MICs were generally stable for all antimicrobial agents except azithromycin, for which an increase in median MIC was observed from 2017 (0.25 µg/mL). There was no genetic resistance to ceftriaxone; 8% of samples displayed resistance mutations against cefixime, primarily located in the penA gene. Resistance to azithromycin increased from 2% in 2013 to 12% in 2020. MtrD mosaic had the highest impact on azithromycin susceptibility; 47% of the resistant isolates showed this mutation. The majority of cases of gonorrhoea were treated successfully with either ceftriaxone or a ceftriaxone/azithromycin regime. Two treatment failures occurred under monotherapy with doxycycline. Overall, genotypic resistance corresponded significantly to all respective MICs.

CONCLUSIONS

The resistance rate of N. gonorrhoeae to antibiotics has remained stable in Vienna over the last decade, except for azithromycin. The strong correlation found between genetic and phenotypic patterns in this study holds promise for future diagnostics of N. gonorrhoeae resistance based on genotypes.

Structural and Functional Annotation and Molecular Docking Analysis of a Hypothetical Protein from Neisseria gonorrhoeae: An In-Silico Approach

Background

Worldwide, Neisseria gonorrhoeae-related sexually transmitted infections (STIs) continue to be of significant public health concern. This obligate-human pathogen has developed a number of defenses against both innate and adaptive immune responses during infection, some of which are mediated by the pathogen's proteins. Hence, the uncharacterized proteins of N. gonorrhoeae can be annotated to get insight into the unique functions of this organism related to its pathogenicity and to find a more efficient therapeutic target.

Methods

In this study, a hypothetical protein (HP) of N. gonorrhoeae was chosen for analysis and an in-silico approach was used to explore various properties such as physicochemical characteristics, subcellular localization, secondary structure, 3D structures, and functional annotation of that HP. Finally, a molecular docking analysis was performed to design an epitope-based vaccine against that HP.

Results

This study has identified the potential role of the chosen HP of N. gonorrhoeae in plasmid transfer, cell cycle control, cell division, and chromosome partitioning. Acidic nature, thermal stability, cytoplasmic localization of the protein, and some of its other physicochemical properties have also been identified through this study. Molecular docking analysis has demonstrated that one of the T cell epitopes of the protein has a significant binding affinity with the human leukocyte antigen HLA-B∗15 : 01.

Conclusions

The in-silico characterization of this protein will help us understand molecular mechanism of action of N. gonorrhoeae and get an insight into novel therapeutic identification processes. This research will, therefore, enhance our knowledge to find new medications to tackle this potential threat to humankind.

Structural characterization of aspartate-semialdehyde dehydrogenase from Pseudomonas aeruginosa and Neisseria gonorrhoeae

Gonorrhoea infection rates and the risk of infection from opportunistic pathogens including P. aeruginosa have both risen globally, in part due to increasing broad-spectrum antibiotic resistance. Development of new antimicrobial drugs is necessary and urgent to counter infections from drug resistant bacteria. Aspartate-semialdehyde dehydrogenase (ASADH) is a key enzyme in the aspartate biosynthetic pathway, which is critical for amino acid and metabolite biosynthesis in most microorganisms including important human pathogens. Here we present the first structures of two ASADH proteins from N. gonorrhoeae and P. aeruginosa solved by X-ray crystallography. These high-resolution structures present an ideal platform for in silico drug design, offering potential targets for antimicrobial drug development as emerging multidrug resistant strains of bacteria become more prevalent.

Rapid Detection of Neisseria gonorrhoeae Genomic DNA Using Gold Nanoprobes Which Target the Gonococcal DNA Uptake Sequence

The rapid spread of antimicrobial resistant Neisseria gonorrhoeae continues to pose a serious threat to global health. To successfully treat and control gonococcal infections, rapid diagnosis is critical. Currently, nucleic acid amplification tests are the recommended diagnostic, however, these are both technically demanding and time consuming, making them unsuitable for resource-poor clinics. Consequently, there is a substantial need for an affordable, point-of-care diagnostic to use in these settings. In this study, DNA-functionalised gold nanoparticles (gold nanoprobes), with the ability to specifically detect the DNA Uptake Sequence (DUS) of Neisseria gonorrhoeae, were prepared. Using complementary annealing, the gold nanoprobes were shown to hybridise to genomic gonococcal DNA, causing a significant shift in their salt stability. By exploiting the shift in nanoprobe stability under the presence of target DNA, a solution-based colorimetric diagnostic for gonococcal DNA was prepared. Detection of purified genomic DNA was achieved in under 30 minutes, with a detection limit of 15.0 ng. Significantly, testing with DNA extracted from an off-target control organism suggested specificity for Neisseria. These results highlight the potential of DUS-specific gold nanoprobes in the rapid point-of-care diagnosis of gonococcal infections.

72-Hour transport recovery of antimicrobial resistant Neisseria gonorrhoeae isolates using the InTray® GC method

Recovery of Neisseria gonorrhoeae isolates exposed to a range of transport times and temperatures was quantitatively assessed for two transport devices, BioMed Diagnostics' InTray GC® and Copan Diagnostics' Liquid Amies Elution Swab (ESwab®) Collection and Transport System. Respective devices were inoculated with N. gonorrhoeae, exposed to simulated transport conditions and spread-plated from serial dilutions in duplicates onto chocolate agar in order to count CFU (colony-forming units) in the range of 25-250. Baseline CFU/mL averages of time-zero transport for each device was compared to either 24 hour (Eswab) or 72 hour (InTray GC) CFU/mL average to assess recovery of six clinical isolates of N. gonorrhoeae, and differences showing no greater than a 3 log10 (± 10%) decline between comparative time points qualified as acceptable. Our findings suggest that the InTray GC system has the potential to transport clinical isolates for ≤72 hours with acceptable N. gonorrhoeae recovery.

Infectious mimics of rheumatoid arthritis

Rheumatoid arthritis (RA) can have various infectious mimics. As immunosuppressive agents used in treatment can aggravate the underlying infections, correct diagnosis of RA and ruling out infections is important. Numerous viral infections (Parvovirus B19, Hepatitis B, Hepatitis C, Chikungunya and other alphaviruses, human immunodeficiency virus (HIV) and various other viruses), mycobacterial infections (Poncet's disease, tubercular septic arthritis, and leprosy), bacterial arthritis, brucellosis and Lyme disease are among common infections that mimic RA. Widespread travel and tourism, especially to exotic areas, high risk sexual behavior and widespread use of immunosuppressive and chemotherapeutic agents has led to numerous outbreaks of infections in areas where these infections were never reported before. Hence, rheumatologists all over the world should be familiar with musculoskeletal manifestations of infections. History of travel, comorbid fever, skin rash, genital ulcers, urethral discharge, the consumption of unpasteurized milk, lymphadenopathy, tenosynovitis, low platelet count, and positive Mantoux test can offer potential diagnostic clues. Serological testing, cultures, specific radiological signs and deoxyribonucleic Acid (DNA) amplification techniques often aid in diagnosis. Treatment mainly consists of antimicrobial agents, analgesics, and nonsteroidal anti-inflammatory drugs (NSAIDs). However, immunosuppressive agents including steroids and disease modifying anti-rheumatic drugs (DMARDs) are needed occasionally in different refractory and prolonged illnesses. Most of the times, episodes of arthritis are self-limiting and respond to treatment of underlying cause. However, few infections like Chikungunya and Lyme's disease can lead to chronic arthritis as well.

Transport Dynamics of MtrD: An RND Multidrug Efflux Pump from Neisseria gonorrhoeae

The MtrCDE system confers multidrug resistance to Neisseria gonorrhoeae, the causative agent of gonorrhea. Using free and directed molecular dynamics (MD) simulations, we analyzed the interactions between MtrD and azithromycin, a transport substrate of MtrD, and a last-resort clinical treatment for multidrug-resistant gonorrhea. We then simulated the interactions between MtrD and streptomycin, an apparent nonsubstrate of MtrD. Using known conformations of MtrD homologues, we simulated a potential dynamic transport cycle of MtrD using targeted MD techniques (TMD), and we noted that forces were not applied to ligands of interest. In these TMD simulations, we observed the transport of azithromycin and the rejection of streptomycin. In an unbiased, long-time scale simulation of AZY-bound MtrD, we observed the spontaneous diffusion of azithromycin through the periplasmic cleft. Our simulations show how the peristaltic motions of the periplasmic cleft facilitate the transport of substrates by MtrD. Our data also suggest that multiple transport pathways for macrolides may exist within the periplasmic cleft of MtrD.

Potential for Phages in the Treatment of Bacterial Sexually Transmitted Infections

Bacterial sexually transmitted infections (BSTIs) are becoming increasingly significant with the approach of a post-antibiotic era. While treatment options dwindle, the transmission of many notable BSTIs, including Neisseria gonorrhoeae, Chlamydia trachomatis, and Treponema pallidum, continues to increase. Bacteriophage therapy has been utilized in Poland, Russia and Georgia in the treatment of bacterial illnesses, but not in the treatment of bacterial sexually transmitted infections. With the ever-increasing likelihood of antibiotic resistance prevailing and the continuous transmission of BSTIs, alternative treatments must be explored. This paper discusses the potentiality and practicality of phage therapy to treat BSTIs, including Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, Streptococcus agalactiae, Haemophilus ducreyi, Calymmatobacterium granulomatis, Mycoplasma genitalium, Ureaplasma parvum, Ureaplasma urealyticum, Shigella flexneri and Shigella sonnei. The challenges associated with the potential for phage in treatments vary for each bacterial sexually transmitted infection. Phage availability, bacterial structure and bacterial growth may impact the potential success of future phage treatments. Additional research is needed before BSTIs can be successfully clinically treated with phage therapy or phage-derived enzymes.

Symptomatic Female Genital Tract Infections Due to Neisseria meningitidis in Athens, Greece

Neisseria meningitidis is considered as an obligate human pathogen and can cause life-threatening diseases like meningitis and/or septicaemia. Occasionally, it can be recovered from infections outside the bloodstream or central nervous system, like respiratory, ocular, joint, urogenital or other unusual sites. Herein, we present two rare cases of female genital infections due to N. meningitidis within a two-year period (2019-2020), identified as serogroup B (MenB) and Y (MenY), respectively. Genotypic analysis for PorA, FetA and MLST revealed the following characteristics: MenB: 7-12, 14, F5-36, 1572cc and MenY: 5-1,10-1, F4-5, 23cc, respectively. Such unusual presentations should alert the clinicians and microbiologists not to exclude N. meningitidis from routine diagnosis and the need of early detection. This is the first report in Greece, and, to our knowledge, in Europe since 2005 describing meningococcal female genital infections.

Visible colorimetric growth indicators of Neisseria gonorrhoeae for low-cost diagnostic applications

N. gonorrhoeae is one of the most pressing antibiotic resistant threats of our time and low-cost diagnostics that can easily identify antibiotic resistance are desperately needed. However, N. gonorrhoeae responds so uniquely to growth conditions that it cannot be assumed gonorrhea will respond to common microbiological methods used for other pathogenic organisms. In this paper, we explore visual colorimetric indicators of N. gonorrhoeae growth that can be seen without a microscope or spectrophotometer. We evaluate growth media, pH indicators, resazurin-based dyes, and tetrazolium-based dyes for their use in simple colorimetric system. Overall, we identified Graver Wade media as the best at supporting robust gonococcal growth while also providing the least background when analyzing results of colorimetric tests. XTT, a tetrazolium-based dye, proved to show to brightest color change over time and not negatively impact the natural growth of N. gonorrhoeae. However, other dyes including PrestoBlue, MTT, and NBT are less expensive than XTT and work well when added after bacterial growth has already occurred. By identifying the specific use cases of these dyes, this research lays the groundwork for future development of a color-based antibiotic susceptibility low-cost test for N. gonorrhoeae.

PrintrLab incubator: A portable and low-cost CO2 incubator based on an open-source 3D printer architecture

Growth in open-source hardware designs combined with the decreasing cost of high-quality 3D printers have supported a resurgence of in-house custom lab equipment development. Herein, we describe a low-cost (< $400), open-source CO2 incubator. The system is comprised of a Raspberry Pi computer connected to a 3D printer controller board that has controls for a CO2 sensor, solenoid valve, heater, and thermistors. CO2 is supplied through the sublimation of dry ice stored inside a thermos to create a sustained 5% CO2 supply. The unit is controlled via G-Code commands sent by the Raspberry Pi to the controller board. In addition, we built a custom software application for remote control and used the open-source Grafana dashboard for remote monitoring. Our data show that we can maintain consistent CO2 and temperature levels for over three days without manual interruption. The results from our culture plates and real-time PCR indicate that our incubator performed equally well when compared to a much more expensive commercial CO2 incubator. We have also demonstrated that the antibiotic susceptibility assay can be performed in this low-cost CO2 incubator. Our work also indicates that the system can be connected to incubator chambers of various chamber volumes.

SERS-based sensor for the detection of sexually transmitted pathogens in the male swab specimens: A new approach for clinical diagnosis

The surface-enhanced Raman scattering (SERS) has been widely tested for its usefulness in microbiological studies, providing many information-rich spectra which are a kind of 'whole-organism fingerprint' and enabling identification of bacterial species. Here we show, previously not considered, the comprehensive SERS-chemometric analysis of five bacterial pathogens, namely Neisseria gonorrhoeae, Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, and Haemophilus ducreyi, all being responsible for sexually transmitted diseases (STDs). In the designed biosensor, the direct, intrinsic format of the spectroscopic analysis was adopted for the SERS-based screening of gonorrhea and chlamydiosis due to vibrational analysis of men's urethra swabs. Our experiments demonstrated that the applied method enables identification the individual species of the Neisseria genus with high accuracy. In order to differentiate the sexually transmitted pathogens and to classify the clinical samples of male urethra swabs, three multivariate methods were used. In the external validation the created models correctly classified the men's urethra swabs with prediction accuracy reaching 89% for SIMCA and 100% for PLS-DA. As a result, the developed protocol enables: (i) simple and non-invasive analysis of clinical samples (the collection of urethra swabs specimens could be carried out at different points of care, such as doctor's office); (ii) fast analysis (<15 min); (iii) culture-free identification; (iv) sensitive and reliable SERS-based diagnosis of STD. The simplicity of the developed detection procedure, supported by high sensitivity, reproducibility, and specificity, open a new path in the improvement of the point-of-care applications.

Neisseria gonorrhoeae Multivalent Maxibody with a Broad Spectrum of Strain Specificity and Sensitivity for Gonorrhea Diagnosis

Gonorrhea is one of the most common, but still hidden and insidious, sexually transmitted diseases caused by Neisseria gonorrhoeae (gonococci). However, the diagnosis and treatment of gonorrhea are hampered by antigenic variability among gonococci, the lack of acquired immunity, and antimicrobial resistance. Further, strains resistant to cephalosporins, including ceftriaxone, the last line of defense, represent a growing threat, which prompted us to develop gonococci-specific diagnostic antibodies with broad-spectrum binding to gonococci strains to generate gonorrhea-detecting reagents. This study reports the identification of gonococci antibodies via bio-panning on gonococci cells using scFv-phage libraries. Reformatting the lead scFv-phage Clones 1 and 4 to a multivalent scFv1-Fc-scFv4 maxibody increased the sensitivity by up to 20-fold compared to the single scFv-Fc (maxibody) alone. Moreover, the multivalent maxibody showed broader cross-reactivity with clinical isolates and the ceftriaxone antibiotic-resistant World Health Organization (WHO) reference strain L. In contrast, the selected antibodies in the scFv-phage, maxibody, and multivalent maxibody did not bind to N. sicca, N. meningitides, and N. lactamica, suggesting the clinical and pharmaceutical diagnostic value of these selected antibodies for gonorrheal infections. The present study illustrates the advantages and potential application of multivalent maxibodies to develop rapid and sensitive diagnostic reagents for infectious diseases and cancer.

Sexually transmitted infections in pregnancy - An update on Chlamydia trachomatis and Neisseria gonorrhoeae

Routine screening for Chlamydia and gonococcal infection in pregnancy is not widespread, especially in low- and middle-income countries (LMICs), despite their potential adverse consequences on pregnancy outcome. We conducted a systematic literature search of three major databases to review current literature surrounding Chlamydia trachomatis and Neisseria gonorrhoeae infections in pregnancy. We discuss the epidemiology and burden of both infections, detection methods, potential adverse feto-maternal and infant outcomes and provide an overview of treatment options. A total of 67 articles met the inclusion criteria. The prevalence of C. trachomatis and N. gonorrhoeae across all trimesters ranged between 1.0%-36.8% and 0-14.2% worldwide, respectively. The most common diagnostic method is the Nucleic acid amplification test (NAAT). In pregnancy, chlamydia is associated with preterm birth, spontaneous miscarriage, stillbirth and neonatal conjunctivitis, while gonorrhoea is mainly associated with preterm birth and stillbirth. Amoxicillin, erythromycin and azithromycin showed similar efficacy in the treatment of chlamydia in pregnancy, while ceftriaxone and cefixime were effective in treating gonorrhoea in pregnancy. Being largely asymptomatic infections in women, we opine that detection strategies with locally appropriate tools should be combined with the syndromic approach in LMICs, where there is a high burden of disease.

Developing target product profiles for Neisseria gonorrhoeae diagnostics in the context of antimicrobial resistance: An expert consensus

BACKGROUND

There is a need for a rapid diagnostic point of care test to detect Neisseria gonorrhoeae (NG) infection to prevent incorrect, lack or excess of treatment resulting from current syndromic management in low-resource settings. An assay to identify NG antimicrobial resistance (AMR) is also highly desirable to facilitate antibiotic stewardship. Here we describe the development of two target product profiles (TPPs): one for a test for etiological diagnosis of NG and Chlamydia trachomatis (CT) (TPP1) and one for the detection of NG AMR/susceptibility (TPP2).

METHODS

Draft TPPs were initially developed based on a landscape analysis of existing diagnostics and expert input. TPPs were refined via an online Delphi survey with two rounds of input from 68 respondents. TPP characteristics on which <75% of non-industry respondents agreed were further discussed and revised by an expert working group.

RESULTS

The need for a test to identify NG in patients with urethral or vaginal discharge was identified as a minimal requirement of TPP1, with a test that can diagnose NG in asymptomatic patients as the optimal requirement. A sensitivity of 80% was considered acceptable, either in context of syndromic management or screening high-risk populations. For TPP2, the agreed minimal requirement was for a test to be used at level 2 healthcare facilities and above, with an optimal requirement of level 1 or above. A lateral flow format was preferred for TPP1, while it was considered likely that TPP2 would require a molecular format. A total of 31 test characteristics were included in TPP1 and 27 in TPP2.

CONCLUSIONS

Following the working group revisions, TPPs were posted online for public feedback for two months, and are now finalized. The final TPPs are currently guiding the development of new diagnostics that meet the defined characteristics to reach the market within two years.

A systematic review and meta-analysis of different diagnostic procedures to detect gonococcus infection in resource-limited scenario

Context

Neisseria gonorrhoeae is a Gram-negative diplococcus, an obligate human pathogen, and the etiologic agent of the sexually transmitted infection (STI), gonorrhoea. culture is the standard procedure for diagnosis, which may be supported by nucleic acid tests and microscopy.

Aims

To determine the best possible method of diagnosis for Gonococcus infection in resource-limited settings.

Settings and Design

The meta-analyses were designed to determine the difference in diagnosis between Culture and nucleic acid amplification tests (NAATs) and also between the different Amplification Tests and widely available Roche COBAS AMPLICOR test.

Subjects and Methods

Databases searched were Pubmed, Medline, Google Scholar and Cochrane reviews. Risk ratio (RR) with 95% confidence intervals was estimated for the dichotomous outcomes. The random-effect model was applied for all the studies in the analysis.

Statistical Analysis Used

The meta-analysis was computed in RevMan Version 5.3, Copenhagen, Denmark.

Results

In the first analysis, NAATs significantly improved the chances of detection in comparison to the standard culture and final RR was 1.24 (1.05-2.51), which put the diamond on the right of no-effect axis, indicating more positives by NAATs. In the second analysis, AMPLICOR had the more positive results, which may have indicated better detection rate, as well as less specificity and final RR was 0.809 (0.737-0.888), which put the diamond on the left of the non-effect axis, indicating more positives by AMPLICOR.

Conclusions

In a resource-limited scenario like India, the syndromic management of STIs are considered to be the norm. A positive diagnosis is only given if the tests are confirmed by Culture, as it is still considered to be the gold standard of diagnosis. However, in many cases, due to suboptimal transportation and lack of proper handling, culture in unable to grow even if the patient is infected. In such cases, Nucleic Acid Tests should be able to detect an infection.

The frontiers of addressing antibiotic resistance in Neisseria gonorrhoeae

The sexually transmitted infection gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae, can cause urethritis, cervicitis, and systemic disease, among other manifestations. N. gonorrhoeae has rapidly rising incidence along with increasing levels of antibiotic resistance to a broad range of drugs including first-line treatments. The rise in resistance has led to fears of untreatable gonorrhea causing substantial disease globally. In this review, we will describe multiple approaches being undertaken to slow and control this spread of resistance. First, a number of old drugs have been repurposed and new drugs are being developed with activity against Neisseria gonorrhoeae. Second, vaccine development, long an important goal, is advancing. Third, new diagnostics promise rapid detection of antibiotic resistance and a shift from empiric to tailored treatment. The deployment of these new tools for addressing the challenge of antibiotic resistance will require careful consideration to provide optimal care for all patients while extending the lifespan of treatment regimens.

Global epidemiology of Neisseria gonorrhoeae in infertile populations: systematic review, meta-analysis and metaregression

Objective

To provide an in-depth systematic assessment of the global epidemiology of gonorrhoea infection in infertile populations.

Methods

A systematic literature review was conducted up to 29 April 2019 on international databases and WHO regional databases, and reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All prevalence measures of gonorrhoea infection among infertile populations, based on primary data, qualified for inclusion. Infertile populations were broadly defined to encompass women/men undergoing infertility evaluation or treatment (infertility clinic attendees and partners). Pooled mean prevalence by relevant strata was estimated using random-effects meta-analysis. Associations with prevalence and sources of heterogeneity were explored using metaregression. Risk of bias was assessed using four quality domains.

Findings

A total of 147 gonorrhoea prevalence studies were identified from 56 countries. The pooled mean prevalence of current gonorrhoea infection was estimated globally at 2.2% (95% CI 1.3% to 3.2%), with the highest prevalence in Africa at 5.0% (95% CI 1.9% to 9.3%). The mean prevalence was higher for populations with tubal factor infertility (3.6%, 95% CI 0.9%–7.7%) and mixed cause and unexplained infertility (3.6%, 95% CI 0.0% to 11.6%) compared with other diagnoses, such as ovarian and non-tubal infertility (0.1%, 95% CI 0.0% to 0.8%), and for secondary (2.5%, 95% CI 0.2% to 6.5%) compared with primary (0.5%, 95% CI 0.0% to 1.7%) infertility. Metaregression identified evidence of variations in prevalence by region and by infertility diagnosis, higher prevalence in women than men and a small-study effect. There was a trend of declining prevalence by about 3% per year over the last four decades (OR=0.97, 95% CI 0.95 to 0.99).

Conclusions

Gonorrhoea prevalence in infertile populations is several folds higher than that in the general population, with even higher prevalence in women with tubal factor infertility and in individuals with secondary infertility. These findings support the potential role of gonorrhoea in infertility and suggest that some infertility is possibly preventable by controlling gonorrhoea transmission.

PROSPERO registration number

CRD42018102934.

Neisseria gonorrhoeae positivity in clients presenting as asymptomatic contacts of gonorrhoea at a sexual health centre

Background Previous guidelines at the Sydney Sexual Health Centre (SSHC) recommended empirical antibiotic treatment for asymptomatic contacts of Neisseria gonorrhoeae at the time of testing. With increasing concerns around gonorrhoea antibiotic resistance, it has been suggested that asymptomatic contacts should only be treated based on test results. Methods: This retrospective study of data from the SSHC electronic medical record included a total of 295 gonorrhoea contacts from 1 January 2018 to 30 June 2018. The primary outcome was the proportion of asymptomatic gonorrhoea contacts with a positive gonorrhoea result from any anatomical site. Statistically significant differences in gonorrhoea positivity according to gender, sexual preference, use of PrEP, sex worker status, country of birth, preferred language and number of partners, were calculated using Fisher’s exact test. Results: The overall proportion of asymptomatic gonorrhoea contacts with a positive gonorrhoea result was 27.1% (95% CI: 22.1–32.6%). The proportion of gonorrhoea positivity was significantly higher in females compared to males (52.0% vs 25.7%, P &lt; 0.01), gay and bisexual men compared to heterosexual men (28.7% vs 0%, P &lt; 0.01) and non-users of PrEP compared to PrEP users (31.2% vs 12.5%, P &lt; 0.05). No statistically significant differences in gonorrhoea positivity were found in subgroups divided by sex worker status, country of birth, preferred language and number of partners. Conclusion: The relatively low gonorrhoea positivity rate (27.1%) in asymptomatic gonorrhoea contacts at the SSHC between January and June 2018 supports guideline changes to no longer provide empirical antibiotic treatment to asymptomatic contacts.

Atypical, Yet Not Infrequent, Infections with Neisseria Species

Neisseria species are extremely well-adapted to their mammalian hosts and they display unique phenotypes that account for their ability to thrive within niche-specific conditions. The closely related species N. gonorrhoeae and N. meningitidis are the only two species of the genus recognized as strict human pathogens, causing the sexually transmitted disease gonorrhea and meningitis and sepsis, respectively. Gonococci colonize the mucosal epithelium of the male urethra and female endo/ectocervix, whereas meningococci colonize the mucosal epithelium of the human nasopharynx. The pathophysiological host responses to gonococcal and meningococcal infection are distinct. However, medical evidence dating back to the early 1900s demonstrates that these two species can cross-colonize anatomical niches, with patients often presenting with clinically-indistinguishable infections. The remaining Neisseria species are not commonly associated with disease and are considered as commensals within the normal microbiota of the human and animal nasopharynx. Nonetheless, clinical case reports suggest that they can behave as opportunistic pathogens. In this review, we describe the diversity of the genus Neisseria in the clinical context and raise the attention of microbiologists and clinicians for more cautious approaches in the diagnosis and treatment of the many pathologies these species may cause.

Neisseria gonorrhoeae uses cellular proteins CXCL10 and IL8 to enhance HIV-1 transmission across cervical mucosa

Problem

Neisseria gonorrhoeae (NG) infection has been shown to increase sexual transmission of HIV‐1. However, the mechanism of NG‐induced enhanced HIV‐1 transmission is unknown.

Methods

(a) The cervical tissues were exposed to NG, and cytokine induction was monitored by measuring cytokine proteins in culture supernatants and cytokine mRNAs in tissues. (b) Transcription and replication of HIV‐1 in TZM‐bl, U1, and ACH2 cells were measured by Beta‐Gal activity and p24 proteins in the supernatant, respectively. (c) HIV‐1 transmission was assayed in an organ culture system by measuring transmitted HIV‐1 in supernatant and HIV‐1 gag mRNA in the tissues. (d) Transcriptome analysis was done using second generation sequencing.

Results

(a) NG induced membrane ruffling of epithelial layer, caused migration of CD3+ cells to the intraepithelial region, and induced high levels of inflammatory cytokines IL‐1β and TNF‐α. (b) NG‐induced supernatants (NGIS) increased HIV‐1 transcription, induced HIV‐1 from latently infected cells, and increased transmission of HIV‐1 across cervical mucosa. (c) Transcriptome analysis of the epithelial layer of the tissues exposed to NG, and HIV‐1 showed significant upregulation of CXCL10 and IL8. IL‐1β increased the induction of CXCL10 and IL‐8 expression in cervical mucosa with a concomitant increase in HIV‐1 transmission.

Conclusion

We present a model in which IL‐1β produced from cervical epithelium during NG exposure increases CXCL10 and IL8 in epithelia. This in turn causes upon HIV‐1 infection, the migration of HIV‐1 target cells toward the subepithelium, resulting in increased HIV‐1 transcription in the sub‐mucosa and subsequent enhancement of transmission across cervical mucosa.

Prevalence and factors associated with gonorrhea infection with respect to anatomic distributions among men who have sex with men

INTRODUCTION

Gonorrhea (GC) infection caused by Neisseria gonorrhoeae has been steadily increasing in Thailand over the last decade. Men who have sex with men (MSM) are at high risk for gonorrhea infection.

MATERIALS AND METHODS

In this study, we determined the prevalence of and risk factors associated with gonococcal infections by three anatomical sites among MSM. We have conducted a cross-sectional analysis of a sexually transmitted disease (STD), gonorrhea among MSM attending two STD clinics in Khon Kaen, Thailand. We included 358 MSM over 18 years of age. Data were collected using self-administered questionnaire. In each participant, an oropharyngeal, anorectal, and endourethral swab were tested with culture and nucleic acid amplification test (NAAT). However, 267 urine samples were tested by both methods. Factors associated with gonorrhea infections were assessed using univariate and multivariate logistic regression.

RESULTS

One hundred and ninety-five out of 358 (54.47%) MSM tested were found to be positive for gonorrhea using a porA gene targeted NAAT by Real-time PCR with TaqMan probes, but there was no positive result by culture. The gonorrheal prevalence for male genital site, anal, and oropharyngeal, were 34.73% (95%CI 33.07, 45.08), 29.01% (95%CI 24.61, 34.33), and 27.93% (95%CI 23.35, 32.89), respectively, while 5.9% (21/355) were positive for gonococcal infection in all anatomic sites (oropharynx + anus + urethra) of one participant. Previous history of diagnosed STDs was a significant factor associated urethral gonorrhea (odds ratio = 3.52, 95%CI 1.87-6.66, P Value< 0.001). In addition, having more than one partner was increased urethral gonorrhea (adjusted odds ratio = 2.26, 95%CI 1.10-4.68, P Value = 0.026). 100% of condom use was found decreasing urethral infection (adjusted odds ratio = 0.39, 95%CI 0.15-0.99, P Value = 0.046).

CONCLUSIONS

The most common anatomic site of gonorrhea infection was male genital site, and the independent risk factors were having history of diagnosed STDs and having more than one partner in the past 3 months, but 100% condom use was a protective factor of this infection.

Gonorrhea and syphilis co-infection and related risk factors in HIV patients from Shiraz, South of Iran

Background:

Neisseria gonorrhea and Treponema pallidum as an obligate human pathogen are two common causes of sexually transmitted diseases (STDs). The present study aimed to determine the prevalence of N. gonorrhoeae and T. pallidum among human immunodeficiency virus (HIV) patients in the southwest Iran.

Methods:

This retrospective study was performed from 2004 to 2013, on HIV patients who were tested for detection of gonorrhea and syphilis infection at Shiraz HIV/AIDS Research Center. ELISA technique was used for preliminary detection of HIV and confirmed by a Western Blotting test. Gonorrhea was routinely diagnosed using direct Gram-staining and culturing on selective agar. Syphilis was routinely diagnosed by RPR test.

Results:

Of the 806 HIV patients, 39 (2.6%) cases had co-infection with gonorrhea. Compared with mono-HIV infected patients, gonorrhea was significantly more likely among the males (69.4% vs. 92.3%, P=0.002). History of addiction and prison seems to be a significant risk factor for gonorrhea infection (P<0.05). Also, the mean of CD4+lymphocyte was higher among gonorrhea infected patients (368±238 vs. 415±328). Logistic regression analysis showed that sexual contact increased risk of gonococcal infection about 4 fold (OR: 4, CI: 1.7-9.39, P=0.001). None of the HIV patients had syphilis co-infection.

Conclusions:

As a preliminary survey, our findings provided unique information on the prevalence of gonorrhea and syphilis co-infections among HIV patients. Moreover, we introduced the main risk factors associated with gonorrhea co-infection in HIV patients in our region including gender, history of addiction and prison, CD4+lymphocyte count, and transmission routes for effective management of STDs.

Use of the mtrR Gene for Rapid Molecular Diagnosis of Neisseria gonorrhoeae and Identification of the Reduction of Susceptibility to Antibiotics in Endocervical Swabs

BACKGROUND

Neisseria gonorrhoeae is one of the main etiological agents of sexually transmitted diseases. The asymptomatic course of the infection and its resistance to antibiotics can lead to pelvic inflammatory disease and infertility.

OBJECTIVES

We developed a polymerase chain reaction (PCR) test using the methyltetrahydrofolate homocysteine methyltransferase reductase (mtrR) gene to identify N. gonorrhoeae and detect reduced susceptibility to antibiotics.

MATERIAL AND METHODS

We analysed 250 samples of endocervical exudate from infertile women with a negative diagnosis of N. gonorrhoeae. We designed NGmtr primers to detect N. gonorrhoeae and identify the antibiotic-resistant strain.

RESULTS

Of the 250 samples, 60 (24%) tested positive for N. gonorrhoeae using real-time PCR. Our study was validated using the HO primers and the Seeplex STD6 ACE System, with a 100% correlation. Furthermore, the NGmtr primers are specific for N. gonorrhoeae and not for other species. Additionally, the curves generated by real-time PCR differed between wild and variant strains (10.93%). The dissociation temperatures for the wild and variant strains were 86.5 and 89 °C, respectively.

CONCLUSIONS

The NGmtr primers enabled us to identify N. gonorrhoeae strains with or without reduction of susceptibility to antibiotics. Therefore, this work constitutes a tool that will facilitate the diagnosis of this infection for a low cost and improve patient quality of life.

4-Hydroxy-tetrahydrodipicolinate reductase from Neisseria gonorrhoeae - structure and interactions with coenzymes and substrate analog

Neisseria gonorrhoeae, an obligate human pathogen, is a leading cause of communicable diseases globally. Due to rapid development of drug resistance, the rate of successfully curing gonococcal infections is rapidly decreasing. Hence, research is being directed toward finding alternative drugs or drug targets to help eradicate these infections. 4-Hydroxy-tetrahydrodipicolinate reductase (DapB), an important enzyme in the meso-diaminopimelate pathway, is a promising target for the development of new antibiotics. This manuscript describes the first structure of DapB from N. gonorrhoeae determined at 1.85 Å. This enzyme uses NAD(P)H as cofactor. Details of the interactions of the enzyme with its cofactors and a substrate analog/inhibitor are discussed. A large scale bioinformatics analysis of DapBs' sequences is also described.

Multi-centric validation of an in-house-developed beacon-based PCR diagnostic assay kit for Chlamydia and Neisseria and portable fluorescence detector

OBJECTIVE

The development of an accurate, sensitive, specific, rapid, reproducible, stable-at-room-temperature and cost-effective diagnostic kit, and a low-cost portable fluorescence detector to fulfil the requirements of diagnostic facilities in developing countries.

METHODS

We developed the 'Chlamy and Ness CT/NG kit' based on molecular beacons for the detection of Chlamydia trachomatis (CT) and Neisseriagonorrhoeae (NG). Multi-centric evaluation of the CT/NG kit was performed using the commercially available nucleic acid amplification test (NAAT)-based FTD Urethritis basic kit for comparison from December 2014 to November 2016. The stability of the kit reagents at 4 and 37 ˚C and the inter-day reproducibility of results were also analysed.

RESULTS

The sensitivity and specificity of the kit were found to be 95.83 and 100.00 % for the detection of C. trachomatis and 93.24 and 99.75 % for N. gonorrhoeae, respectively, when tested against the commercial kit. The positive predictive value (PPV) was 100.00 and 98.57 %, whereas the negative predictive value (NPV) was 99.54 and 98.79 % for C. trachomatis and N. gonorrhoeae, respectively. Analysis of the kappa statistics enhanced the 'inter-rater' κ=0.976 for Chlamydia and κ=0.943 for Neisseria.

CONCLUSION

Our kit was found to be as sensitive and specific as commercially available kits. Its low cost and ease of use will make it suitable for the routine diagnosis of C. trachomatis and N. gonorrhoeae in the resource-limited settings of developing countries.

Neisseria gonorrhoeae host adaptation and pathogenesis

The host-adapted human pathogen Neisseria gonorrhoeae is the causative agent of gonorrhoea. Consistent with its proposed evolution from an ancestral commensal bacterium, N. gonorrhoeae has retained features that are common in commensals, but it has also developed unique features that are crucial to its pathogenesis. The continued worldwide incidence of gonorrhoeal infection, coupled with the rising resistance to antimicrobials and the difficulties in controlling the disease in developing countries, highlights the need to better understand the molecular basis of N. gonorrhoeae infection. This knowledge will facilitate disease prevention, surveillance and control, improve diagnostics and may help to facilitate the development of effective vaccines or new therapeutics. In this Review, we discuss sex-related symptomatic gonorrhoeal disease and provide an overview of the bacterial factors that are important for the different stages of pathogenesis, including transmission, colonization and immune evasion, and we discuss the problem of antibiotic resistance.

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.

Conventional culture versus nucleic acid amplification tests for screening of urethral Neisseria gonorrhea infection among asymptomatic men who have sex with men

BACKGROUND

Many methods are used to detect urethral Neisseria gonorrhea (NG) infection among asymptomatic men who have sex with men (MSM). The objective of this study was to define the performance of conventional culture compared to real-time polymerase chain reaction (PCR) for diagnosis of asymptomatic urethral gonorrhea among MSM.

METHODS

In this cross-sectional study, 147 clinical specimens for NG testing from asymptomatic participants were evaluated. MSM >18 years old who consented to undergo urethral swab and collection of urine samples from two clinics (one was the sexually transmitted diseases (STDs) mobile clinic and the second was the antiretroviral clinic) located in Khon Kaen, Thailand, were recruited. For conventional culture, 147 swab specimens from urethra were analyzed. For real-time PCR, the same samples and collected urine (147 urethral swab and 62 urine) were evaluated.

RESULTS

Participants were predominately older aged (mean age: 28.79 years, range: 18-54), asymptomatic (99.3%), and engaged in sex with multiple partners (63% had at least two partners and 36% had at least three partners during the previous 3 months). Twenty-five MSM (17%) had history of STD, mainly human immunodeficiency virus infection. Of the 147 specimens, 42 were positive for NG detected by real-time PCR (prevalence: 28.6%, 95% confidence interval [CI]: 24.8%-32.4%), while none of the 147 MSM were positive for NG detected by conventional culture (prevalence: 0.0%, 95% CI: 0.0%-7.3%). These findings indicated that conventional culture had low sensitivity but high specificity (0.0% and 100%, respectively). We could not demonstrate that many of the factors that were identified in other studies were associated to increased (or decreased) risk of urethral gonococcal infection in our population.

CONCLUSION

In asymptomatic MSM, nucleic acid amplification tests are more appropriate for screening of urethral NG infection than conventional culture. However, the culture method is necessary for monitoring emerging antimicrobial resistance and to inform gonorrhea treatment guidelines.

Gonorrhoea diagnostics: An update

Diagnosis of gonorrhoea is an ongoing challenge. The organism is fastidious requiring meticulous collection and transport for successful cultivation. Asymptomatic infections are common which go undetected by conventional methods thereby leading to continued transmission and the risk of complications. The nucleic acid amplification tests, now increasingly used in developed countries, offer improved sensitivity compared to bacterial culture. However, these continue to suffer sequence related problems leading to false positive and false negative results. Further, these cannot be used for generation of data on antibiotic susceptibility because genetic markers of antibiotic resistance to recommended therapies have not been fully characterised. They are unaffordable in a setting like ours where reliance is placed on syndromic approach for sexually transmitted infection (STI) management. The use of syndromic approach has resulted in a considerable decline in the number of Neisseria gonorrhoeae isolates that have been cultured for diagnostic purposes. Many laboratories formerly doing so are no longer performing culture for gonococci, and the basic skills have been lost. There is a need to not only revive this skill but also adopt newer technologies that can aid in accurate diagnosis in a cost-effective manner. There is room for innovation that can facilitate the development of a point-of-care test for this bacterial STI.

Clinical biospecimens: reference materials, certified for nominal properties?

This report makes the case for clinical biospecimens to be certified for nominal properties, in particular the diagnosis, and to attain the level of Reference Materials. Clinical certified biospecimens that are collected, processed, characterized, stored, and distributed by biobanks are urgently needed to facilitate diagnostic test development, evaluation, and quality assurance. Four examples are provided to illustrate this purpose and the certification approaches that could be applied are proposed.

Highly specific and efficient primers for in-house multiplex PCR detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum

Background

Although sophisticated methodologies are available, the use of endpoint polymerase chain reaction (PCR) to detect 16S rDNA genes remains a good approach for estimating the incidence and prevalence of specific infections and for monitoring infections. Considering the importance of the early diagnosis of sexually transmitted infections (STIs), the development of a sensitive and affordable method for identifying pathogens in clinical samples is needed. Highly specific and efficient primers for a multiplex polymerase chain reaction (m-PCR) system were designed in silico to detect the 16S rDNA genes of four bacteria that cause genital infections, and the PCR method was developed.

Methods

The Genosensor Probe Designer (GPD) (version 1.0a) software was initially used to design highly specific and efficient primers for in-house m-PCR. Single-locus PCR reactions were performed and standardised, and then primers for each locus in turn were added individually in subsequent amplifications until m-PCR was achieved. Amplicons of the expected size were obtained from each of the four bacterial gene fragments. Finally, the analytical specificity and limits of detection were tested.

Results

Because they did not amplify any product from non-STI tested species, the primers were specific. The detection limits for the Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum primer sets were 5.12 × 10⁵, 3.9 × 10³, 61.19 × 10⁶ and 6.37 × 10⁵ copies of a DNA template, respectively.

Conclusions

The methodology designed and standardised here could be applied satisfactorily for the simultaneous or individual detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum. This method is at least as efficient as other previously described methods; however, this method is more affordable for low-income countries.