Future Prospects for Neisseria gonorrhoeae Treatment

Neisseria gonorrhoeae isolates resistant to extended spectrum cephalosporins and macrolides isolated from symptomatic men in western Kenya

BACKGROUND

We characterized the antimicrobial resistance (AMR) profiles of Neisseria gonorrhoeae (NG) isolated from symptomatic men at a sexually transmitted infection clinic in Kisumu, Kenya.

METHODS

Two urethral swabs were obtained from symptomatic men between 2020 and 2022, one for Gram's stain and the other inoculated directly onto modified Thayer-Martin media containing 1% VCNT and 1% IsoVitaleX enrichment. Culture results were confirmed by colony morphology, Gram's stain and oxidase test. Duplicate isolates were shipped to Uniformed Services University for confirmation and characterization. Susceptibility to eight drugs was assessed by E-test. Agar dilution confirmed resistance to ceftriaxone, cefixime, and azithromycin. Susceptibility, intermediate resistance (IR), and resistance (R) were determined according to published criteria.

RESULTS

Of 154 enrolled participants, 112 were culture-positive for NG. Agar dilution results in 110 (98.2%) showed the following: azithromycin-R (1.8%), and 4.5% R or IR to ceftriaxone or cefixime: ceftriaxone-R (0.9%), ceftriaxone-IR (2.7%), and cefixime-IR (2.7%). By E-test, most isolates were IR or R to tetracycline (97.2%), penicillin (90.9%), and ciprofloxacin (95.4%).

CONCLUSIONS

We detected NG with resistance to azithromycin and ceftriaxone, indicating a growing threat to the current Kenyan dual syndromic treatment of urethritis with cephalosporin plus macrolides. Ongoing AMR surveillance is essential for effective drug choices.

A systematic review of Neisseria gonorrhoeae drug resistance development in South Africa

In South Africa, basic healthcare centres treat sexually transmitted infections (STIs) using a syndromic approach. In line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, a complete study of all randomised controlled trials and surveillance data relevant to N. gonorrhoeae antibiotic resistance was conducted. To discover papers published between 2002 and 2022, searches were undertaken using PubMed, EMBASE and any other relevant databases. This systematic review extracted a total of 463 articles published between 2002 and 2022 from a variety of online research sources. Seven South African provinces were represented in the studies that were assessed. Mpumalanga and the North West Province did not have any studies that described the identification and monitoring of antimicrobial resistance (AMR). This study presents data obtained from a comprehensive analysis of 2140 isolates, in which we examined the presence of one or more antibiotic resistance. Our findings revealed that out of these samples, 1891 isolates exhibited antimicrobial properties; tetracycline was the antimicrobial resistance that was found the most often (30%), followed by ciprofloxacin (19%) and penicillin (17%). The mean of the isolates was 143, the upper 95% mean was 243, and the standard deviation (SD) was 181.6. All microbiological identification and susceptibility testing processes must be standardised and improved so national organisations can monitor AMR. The nation's health community must address all identified areas of concern to avoid AMR.

An NIR-II-enhanced nanozyme to promote wound healing in methicillin-resistant Staphylococcus aureus infections

Deep tissue bacterial infections, especially methicillin-resistant Staphylococcus aureus (MRSA) infections, pose challenges to clinical therapy due to their low debridement efficiency and relapsing. Molybdenum disulfide (MoS2) is used in the antibacterial field as a classic photothermal agent (NIR-I) with good biocompatibility. However, due to its limited NIR-I tissue penetration ability and single treatment mode, MoS2 has poor therapeutic effects on deep tissue infection. Herein, we prepared a defect-type hybrid 2H-MoS2 nanozyme (MoWS2) using hydrothermal method fabricate the MoWS2 composite, which is a new antibacterial strategy involving photothermal and enzyme catalysis, and further enhances the activity of the nanozyme through overheating. The regulation of 2H-MoS2 defects through tungsten ion doping endows MoWS2 with better near-infrared two-region absorption (NIR-II) and enzyme catalytic performance. Antibacterial activity experiments in vitro have shown that MoWS2 can achieve efficient bactericidal activity and biofilm clearance through hyperthermia and reactive oxygen species (ROS). Deep MRSA infection experiments have shown that MoWS2 rapidly removes bacteria from subcutaneous infected tissues through photothermal therapy (PTT) and chemodynamic therapy (CDT), accelerates the dissipation of abscesses, and promotes the healing of infected wounds. Additionally, the versatile treatment mode of MoWS2 was further confirmed through tissue sectioning and immunofluorescence staining analysis. Overall, these results provide a feasible approach for achieving efficient treatment of deep tissue infections through tungsten ion doping to regulate defective 2H-MoS2. STATEMENT OF SIGNIFICANCE: The photothermal effect of MoS2 nanosheets in the NIR-I (650-900 nm) window in anti-MRSA therapy is considered to be highly reliable and efficient in PTA. However, most of the developed PPT therapies or antimicrobial systems based on PTT therapies developed with 1T-MoS2 have in vivo sterilization temperatures of more than 55°C, which have the risk of damaging the normal tissues of the skin. In this study, we prepared W@MoS2 with a good photothermal effect (36.9%) in the NIR-II window and good peroxidase-like activity. The combined effect of PTT and CDT has a stronger bactericidal effect while avoiding high-temperature damage, which makes the W@MoS2 material more advantageous in terms of antimicrobial effect.

Dinner date: Neisseria gonorrhoeae central carbon metabolism and pathogenesis

Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea, is a human-adapted pathogen that does not productively infect other organisms. The ongoing relationship between N. gonorrhoeae and the human host is facilitated by the exchange of nutrient resources that allow for N. gonorrhoeae growth in the human genital tract. What N. gonorrhoeae 'eats' and the pathways used to consume these nutrients have been a topic of investigation over the last 50 years. More recent investigations are uncovering the impact of N. gonorrhoeae metabolism on infection and inflammatory responses, the environmental influences driving N. gonorrhoeae metabolism, and the metabolic adaptations enabling antimicrobial resistance. This mini-review is an introduction to the field of N. gonorrhoeae central carbon metabolism in the context of pathogenesis. It summarizes the foundational work used to characterize N. gonorrhoeae central metabolic pathways and the effects of these pathways on disease outcomes, and highlights some of the most recent advances and themes under current investigation. This review ends with a brief description of the current outlook and technologies under development to increase understanding of how the pathogenic potential of N. gonorrhoeae is enabled by metabolic adaptation.

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.

Effect of C7-3-Peptide-Loaded Chitosan Nanoparticles Against Multi-Drug-Resistant Neisseria gonorrhoeae

Introduction

The emergence of Neisseria gonorrhoeae-resistant strains represents one of the most urgent global threats. In this regard, C7-3 peptide is one of the anti-virulence therapies that has demonstrated promising anti-gonococcal activity. Accordingly, this research aimed to formulate C7-3 peptide and its derivatives in chitosan nanoparticles.

Methods

The peptide loaded chitosan nanoparticles were prepared using ion gelation method, and their physicochemical characteristics were investigated. The anti-gonococcal and antibiofilm activity of prepared NPs was assessed, and their cytotoxicity in human ovarian cells was evaluated.

Results

All prepared NPs were optimized for the smallest particle size of 136.9 to 168.3 nm. The EE% of C7-3, C7-3m1, and C7-3m2 CNPs reached 90.2, 92.5, and 91.8%, respectively. An in vitro release study demonstrated a continuous sustained-release pattern of C7-3 peptide from NPs. The SDS-PAGE assay confirmed the integrity of C7-3 peptide after the fabrication process. When comparing each peptide alone, the generated NPs demonstrated higher anti-gonococcal and anti-biofilm effectiveness against standard and resistant bacterial strains under anaerobic conditions. The cytotoxicity experiments revealed the cytocompatibility of NPs in HeLa cell lines. Given the advantages of enhanced anti-gonococcal activity of the C7-3 peptide and its derivatives when loaded with CNPs, as well as the antimicrobial properties of chitosan NPs, the reported NPs have great potential in the treatment of gonococcal infection.

Ameliorating Gonorrhea: Recent Therapeutic Adaptations and Scope to Improve its Prevailing Condition

BACKGROUND

Gonorrhea is a sexually transmitted infection (STI) caused by the bacteria Neisseria gonorrhoeae. According to recent research, the prevalence of gonorrhea has been increasing in many parts of the world, with some areas reporting high rates of antibiotic resistance. In the United States, the Centers for Disease Control and Prevention (CDC) reported that the number of reported gonorrhea cases increased by 56% between 2015 and 2019. Globally, the World Health Organization (WHO) estimated that there were 87 million new cases of gonorrhea in 2016, with the highest burden of infection in low- and middle-income countries. Research has also shown that gonorrhea is becoming increasingly resistant to conventional antibiotics, increasing the prevalence of gonorrhea. This raises concerns and challenges in disease management.

OBJECTIVES

The present review gives updated insight on the current state of the disease, challenges, and shortcomings of existing approaches along with the modern and alternative direction like vaccine development, its challenges, and scope to confront the existing state of drug resistance and increased rate of incidence. Alternative strategies like immunotherapy and phage therapy along with recent antibiotics researched for the treatment of gonorrhea.

CONCLUSION

The review provides a thorough insight into the current state of the disease and various available methods used currently and recommended by WHO. To overcome disease prevalence, various alternate therapies are coming into the limelight. However, scientists and researchers show a lack of interest in the drug development and research of gonorrhea, due to less commercial scope, lack of funding, and limited scope in the scientific scenario. These hurdles need to be overcome to meet the WHO vision of reducing gonorrhea by 90% by 2030. So, there is a need to optimize the drug therapy (optimizing dosing schedule, and precision monitoring) to reduce the chance of drug resistance. Also, there is a wide scope for drug and therapeutic system development.

Emerging threat of antimicrobial resistance in Neisseria gonorrhoeae: pathogenesis, treatment challenges, and potential for vaccine development

The continuous rise of antimicrobial resistance (AMR) is a serious concern as it endangers the effectiveness of healthcare interventions that rely on antibiotics in the long run. The increasing resistance of Neisseria gonorrhoeae, the bacteria responsible for causing gonorrhea, to commonly used antimicrobial drugs, is a major concern. This has now become a critical global health crisis. In the coming years, there is a risk of a hidden epidemic caused by the emergence of gonococcal AMR. This will worsen the global situation. Infections caused by N. gonorrhoeae were once considered easily treatable. However, over time, they have become increasingly resistant to commonly used therapeutic medications, such as penicillin, ciprofloxacin, and azithromycin. As a result, this pathogen is developing into a true "superbug," which means that ceftriaxone is now the only available option for initial empirical treatment. Effective management strategies are urgently needed to prevent severe consequences, such as infertility and pelvic inflammatory disease, which can result from delayed intervention. This review provides a thorough analysis of the escalating problem of N. gonorrhoeae, including its pathogenesis, current treatment options, the emergence of drug-resistant mechanisms, and the potential for vaccine development. We aim to provide valuable insights for healthcare practitioners, policymakers, and researchers in their efforts to combat N. gonorrhoeae antibiotic resistance by elucidating the multifaceted aspects of this global challenge.

High-throughput bactericidal assays for monoclonal antibody screening against antimicrobial resistant Neisseria gonorrhoeae

Neisseria gonorrhoeae (gonococcus) is an obligate human pathogen and the etiological agent of the sexually transmitted disease gonorrhea. The rapid rise in gonococcal resistance to all currently available antimicrobials has become a significant public health burden and the need to develop novel therapeutic and prophylactic tools is now a global priority. While high-throughput screening methods allowed rapid discovery of extremely potent monoclonal antibodies (mAbs) against viral pathogens, the field of bacteriology suffers from the lack of assays that allow efficient screening of large panels of samples. To address this point, we developed luminescence-based (L-ABA) and resazurin-based (R-ABA) antibody bactericidal assays that measure N. gonorrhoeae metabolic activity as a proxy of bacterial viability. Both L-ABA and R-ABA are applicable on the large scale for the rapid identification of bactericidal antibodies and were validated by conventional methods. Implementation of these approaches will be instrumental to the development of new medications and vaccines against N. gonorrhoeae and other bacterial pathogens to support the fight against antimicrobial resistance.

Emergence of a predominant sequence type ST7363 and the increasing trend of resistance to cefixime and ceftriaxone in Neisseria gonorrhoeae in Southern Taiwan, 2019-2021

BACKGROUND/PURPOSE

Multi-drug resistance and the presence of epidemic lineages of Neisseria gonorrhoeae locally and globally were important clinical and public health issues. We aimed to investigate the molecular epidemiology and the antimicrobial susceptibility profiles of N. gonorrhoeae in Southern Taiwan.

METHODS

Between 2019 and 2021, adult patients who had suspected gonorrhea and attended a urology clinic in southern Taiwan were recruited to participate in this study. Clinical data from medical records and a questionnaire, antimicrobial susceptibility testing using a disk diffusion test in accordance with the guidelines by the Clinical and Laboratory Standards Institute, and Multi-locus sequence typing (MLST) were analyzed.

RESULTS

A total of 500 patients participated in the surveillance study. Among them, 232 N. gonorrhoeae isolates were identified, but only 164 isolates were recovered for further research. ST7363 (n = 83, 50.61%) was found to be the predominant sequence type, followed by ST1583 (n = 24, 14.63%), ST1588 (n = 13, 7.93%), and ST7827 (n = 12, 7.32%). 100% resistance to penicillin and 99.4% non-susceptible rate of ciprofloxacin were observed. The azithromycin resistant rate being 15.24% and the cefixime non-susceptible rate being 17.07% were alarming, both with decreasing trends in susceptibilities during 2019-2021. The 25 azithromycin resistant isolates were mainly belonged to ST7363 (n = 12) and ST7827 (n = 3). Seven (4.2%) isolates were ceftriaxone non-susceptible. Among them, four were assigned to be ST 7827 and three belonged to ST7363.

CONCLUSION

We observed the emergence of a predominant sequence type ST7363 in southern Taiwan. Compared with previous Taiwan studies, the increasing trend of resistance to cefixime and ceftriaxone necessitates clinicians' alertness for clinical treatment response of the extended spectrum cephalosporins and the further surveillance monitor.

Sanguinarine, similar to the MICs of spectinomycin, exhibits good anti-Neisseria gonorrhoeae activity in vitro

The increasing antibiotic resistance of Neisseria gonorrhoeae (NG) is an urgent need to explore new and effective drugs. The antibacterial activities of spectinomycin and sanguinarine against 117 clinical NG isolates and time-kill curve of sanguinarine were evaluated. Almost all isolates were resistant to penicillin (91.5%) and ciprofloxacin (96.5%), 8.5% showed resistance to azithromycin, 10.3% and 10.3% had decreased susceptibility/resistance to ceftriaxone and cefixime, respectively, whereas 100% were susceptible to spectinomycin. The minimum inhibitory concentration (MIC) ranges, MIC₅₀, MIC₉₀ and MIC_mean values of sanguinarine were 2-64 μg/ml, 16 μg/ml, 32 μg/ml and 16.9 μg/ml, respectively, and time-kill curve showed killing of bacteria in a dose-dependent manner during the assay time of 6h, very similar to spectinomycin. Sanguinarine has great potential as an effective and novel anti-NG agent.

In Vitro Evaluation of Tellurium-Based AS101 Compound against Neisseria gonorrhoeae Infectivity

Neisseria gonorrhoeae (GC) is a obligate human pathogen responsible for gonorrhea, one of the most common sexually transmitted infections. The yearly increased multidrug resistance in GC has led to treatment failure clinically, suggesting an urgent need for novel therapy to combat this global health issue. AS101 [ammonium trichloro(dioxoethylene-O,O'-)tellurate], a tellurium-based compound previously used as an immunomodulatory agent, was found to have antimicrobial effects against Klebsiella pneumoniae via a high-throughput drug screening and showed antibacterial activity against Acinetobacter spp. This study aimed to evaluate the in vitro anti-gonococcal activity of AS101, including its antimicrobial activity, biofilm and infectivity inhibition, and potential underlying mechanisms. The agar-dilution-based MIC was used. The inhibition of GC microcolony formation and continual growth by AS101 was assessed by microscopy. The effect of AS101 on GC infectivity was evaluated by infecting endocervical ME180 and colorectal T84 epithelial cell lines. The mode of action was evaluated by a time-killing curve, transmission electron microscopy (TEM), and the level of reactive oxygen species (ROS). The MICs of MS11 and WHO GC isolates were both found to be 0.05 μg/mL. The biofilm formation, continual growth, and infectivity of two epithelial cell lines were significantly decreased with AS101 treatment. The time-kill curve, similar to that of azithromycin, suggested that AS101 is a bacteriostatic antimicrobial. However, TEM and ROS levels implied a mode of action different from that of azithromycin. Our findings highlighted the robust anti-gonococcal activities of AS101, which potentiates its use as a future antimicrobial for GC. IMPORTANCE Neisseria gonorrhoeae is an obligate human pathogen responsible for gonorrhea, one of the most common sexually transmitted infections. The yearly increased multidrug resistance in GC has led to treatment failure clinically, suggesting an urgent need for novel therapy to combat the global health issue. This study aimed to evaluate the in vitro anti-gonococcal activity of a previous immunomodulatory agent, AS101, and its underlying mechanisms. Here, we report that AS101 possesses remarkable anti-gonococcal activity. These findings supported further studies on in vivo experiments and formulations for the clinical application of AS101 as an anti-gonococcal agent.

Alternatives Therapeutic Approaches to Conventional Antibiotics: Advantages, Limitations and Potential Application in Medicine

Resistance to antimicrobials and particularly multidrug resistance is one of the greatest challenges in the health system nowadays. The continual increase in the rates of antimicrobial resistance worldwide boosted by the ongoing COVID-19 pandemic poses a major public health threat. Different approaches have been employed to minimize the effect of resistance and control this threat, but the question still lingers as to their safety and efficiency. In this context, new anti-infectious approaches against multidrug resistance are being examined. Use of new antibiotics and their combination with new β-lactamase inhibitors, phage therapy, antimicrobial peptides, nanoparticles, and antisense antimicrobial therapeutics are considered as one such promising approach for overcoming bacterial resistance. In this review, we provide insights into these emerging alternative therapies that are currently being evaluated and which may be developed in the future to break the progression of antimicrobial resistance. We focus on their advantages and limitations and potential application in medicine. We further highlight the importance of the combination therapy approach, wherein two or more therapies are used in combination in order to more effectively combat infectious disease and increasing access to quality healthcare. These advances could give an alternate solution to overcome antimicrobial drug resistance. We eventually hope to provide useful information for clinicians who are seeking solutions to the problems caused by antimicrobial resistance.

WYBQ-4: a New Bactericidal Agent against Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen that currently poses a serious threat to global health. Novel antimicrobial agents against MRSA are urgently being developed. In this study, we investigated WYBQ-4, which is an effective antibacterial agent with potent bactericidal activity and bactericidal efficiency against MRSA USA300 and clinical isolate strains. In addition, WYBQ-4 exhibited low cytotoxicity without hemolytic activity according to a safety evaluation. Importantly, WYBQ-4 showed potent in vivo efficacy in an MRSA-induced mouse pneumonia model, systemic infection model, and intramuscular infection model. The efficacy of this new cephalosporin against MRSA was associated with a high affinity for penicillin-binding proteins (PBP1, PBP2, PBP3, PBP4, PBP2a) evaluated in a competition assay using bocillin as a reporter. In conclusion, WYBQ-4 has a significant bactericidal effect in vitro and in vivo, indicating that it is a promising compound to control MRSA infection. IMPORTANCE Antibiotic resistance is spreading faster than the introduction of new compounds into clinical practice, causing a public health crisis. Novel antimicrobial agents against MRSA are urgently being developed. In this study, we investigated WYBQ-4, which is an effective antibacterial agent with potent bacteriostatic activity and bactericidal efficiency against MRSA USA300 and clinical isolate strains. WYBQ-4 showed potent in vivo efficacy in MRSA-induced mouse models. Subsequently, we further revealed its antibacterial mechanism. In conclusion, WYBQ-4 has a significant bactericidal effect in vitro and in vivo, indicating that it is a promising compound to control MRSA infection.

Assessment of Antibiotic Resistance and Efflux Pump Gene Expression in Neisseria Gonorrhoeae Isolates from South Africa by Quantitative Real-Time PCR and Regression Analysis

Introduction

Treatment of gonorrhoea infection is limited by the increasing prevalence of multidrug-resistant strains. Cost-effective molecular diagnostic tests can guide effective antimicrobial stewardship. The aim of this study was to correlate mRNA expression levels in Neisseria gonorrhoeae antibiotic target genes and efflux pump genes to antibiotic resistance in our population.

Methods

This study investigated the expression profile of antibiotic resistance-associated genes (penA, ponA, pilQ, mtrR, mtrA, mtrF, gyrA, parC, parE, rpsJ, 16S rRNA, and 23S rRNA) and efflux pump genes (macAB, norM, and mtrCDE), by quantitative real-time PCR, in clinical isolates from KwaZulu-Natal, South Africa. Whole-genome sequencing was used to determine the presence or absence of mutations.

Results

N. gonorrhoeae isolates, from female and male patients presenting for care at clinics in KwaZulu-Natal, South Africa, were analysed. As determined by binomial regression and ROC analysis, the most significant (p ≤ 0.05) markers for resistance prediction in this population, and their cutoff values, were determined to be mtrC (p = 0.024; cutoff <0.089), gyrA (p = 0.027; cutoff <0.0518), parE (p = 0.036; cutoff <0.0033), rpsJ (p = 0.047; cutoff <0.0012), and 23S rRNA (p = 0.042; cutoff >7.754).

Conclusion

Antimicrobial stewardship includes exploring options to conserve currently available drugs for gonorrhoea treatment. There is the potential to predict an isolate as either susceptible or nonsusceptible based on the mRNA expression level of specific candidate markers, to inform patient management. This real-time qPCR approach, with few targets, can be further investigated for use as a potentially cost-effective diagnostic tool to detect resistance.

Molecular Mechanisms of Drug Resistance and Epidemiology of Multidrug-Resistant Variants of Neisseria gonorrhoeae

The paper presents various issues related to the increasing drug resistance of Neisseria gonorrhoeae and the occurrence and spread of multidrug-resistant clones. One of the most important is the incidence and evolution of resistance mechanisms of N. gonorrhoeae to beta-lactam antibiotics. Chromosomal resistance to penicillins and oxyimino-cephalosporins and plasmid resistance to penicillins are discussed. Chromosomal resistance is associated with the presence of mutations in the PBP2 protein, containing mosaic variants and nonmosaic amino acid substitutions in the transpeptidase domain, and their correlation with mutations in the mtrR gene and its promoter regions (the MtrCDE membrane pump repressor) and in several other genes, which together determine reduced sensitivity or resistance to ceftriaxone and cefixime. Plasmid resistance to penicillins results from the production of beta-lactamases. There are different types of beta-lactamases as well as penicillinase plasmids. In addition to resistance to beta-lactam antibiotics, the paper covers the mechanisms and occurrence of resistance to macrolides (azithromycin), fluoroquinolones and some other antibiotics. Moreover, the most important epidemiological types of multidrug-resistant N. gonorrhoeae, prevalent in specific years and regions, are discussed. Epidemiological types are defined as sequence types, clonal complexes and genogroups obtained by various typing systems such as NG-STAR, NG-MAST and MLST. New perspectives on the treatment of N. gonorrhoeae infections are also presented, including new drugs active against multidrug-resistant strains.

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.

Development and application of Cas13a-based diagnostic assay for Neisseria gonorrhoeae detection and azithromycin resistance identification

BACKGROUND

Gonorrhoea, caused by Neisseria gonorrhoeae, has spread worldwide. Strains resistant to most antibiotics, including ceftriaxone and azithromycin, have emerged to an alarming level. Rapid testing for N. gonorrhoeae and its antimicrobial resistance will therefore contribute to clinical decision making for early diagnosis and rational drug use.

METHODS

A Cas13a-based assay (specific high-sensitivity enzymatic reporter unlocking; SHERLOCK) was developed for N. gonorrhoeae detection (porA gene) and azithromycin resistance identification (A2059G, C2611T). Assays were evaluated for sensitivity with purified dsDNA and specificity with 17 non-gonococcal strains. Performance of SHERLOCK (porA) was compared with Roche Cobas 4800 using 43 urine samples. Identification of azithromycin resistance mutations (A2059G, C2611T) was evaluated using a total of 84 clinical isolates and 18 urine samples. Lateral flow was tested for this assay as a readout tool. Moreover, we directly assayed 27 urethral swabs from patients with urethritis to evaluate their status in terms of N. gonorrhoeae infection and azithromycin resistance.

RESULTS

The SHERLOCK assay was successfully developed with a sensitivity of 10 copies/reaction, except 100 copies/reaction for A2059G, and no cross-reaction with other species. Comparison of the SHERLOCK assay with the Cobas 4800 revealed 100% concordance within 18 positive and 25 negative urine samples. Of the 84 isolates, 21 strains with azithromycin resistance mutations were distinguished and further verified by sequencing and MIC determination. In addition, 62.96% (17/27) strains from swab samples were detected with no mutant strains confirmed by sequencing.

CONCLUSIONS

The SHERLOCK assay for rapid N. gonorrhoeae detection combined with azithromycin resistance testing is a promising method for application in clinical practice.

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

There is enormous interest in utilizing biologically active fatty acids and monoglycerides to treat phospholipid membrane-related medical diseases, especially with the global health importance of membrane-enveloped viruses and bacteria. However, it is difficult to practically deliver lipophilic fatty acids and monoglycerides for therapeutic applications, which has led to the emergence of lipid nanoparticle platforms that support molecular encapsulation and functional presentation. Herein, we introduce various classes of lipid nanoparticle technology and critically examine the latest progress in utilizing lipid nanoparticles to deliver fatty acids and monoglycerides in order to treat medical diseases related to infectious pathogens, cancer, and inflammation. Particular emphasis is placed on understanding how nanoparticle structure is related to biological function in terms of mechanism, potency, selectivity, and targeting. We also discuss translational opportunities and regulatory needs for utilizing lipid nanoparticles to deliver fatty acids and monoglycerides, including unmet clinical opportunities.

Preclinical Testing of Vaccines and Therapeutics for Gonorrhea in Female Mouse Models of Lower and Upper Reproductive Tract Infection

Murine models of Neisseria gonorrhoeae lower reproductive tract infection are valuable systems for studying N. gonorrhoeae adaptation to the female host and immune responses to infection. These models have also accelerated preclinical testing of candidate therapeutic and prophylactic products against gonorrhea. However, because N. gonorrhoeae infection is restricted to the murine cervicovaginal region, there is a need for an in vivo system for translational work on N. gonorrhoeae pelvic inflammatory disease (PID). Here we discuss the need for well-characterized preclinical upper reproductive tract infection models for developing candidate products against N. gonorrhoeae PID, and report a refinement of the gonorrhea mouse model that supports sustained upper reproductive tract infection. To establish this new model for vaccine testing, we also tested the licensed meningococcal 4CMenB vaccine, which cross-protects against murine N. gonorrhoeae lower reproductive tract infection, for efficacy against N. gonorrhoeae in the endometrium and oviducts following transcervical or vaginal challenge.

Epidemiology, Treatments, and Vaccine Development for Antimicrobial-Resistant Neisseria gonorrhoeae: Current Strategies and Future Directions

Neisseria gonorrhoeae is the second most common bacterial sexually transmitted infection in the world after Chlamydia trachomatis. The pathogen has developed resistance to every antibiotic currently approved for treatment, and multidrug-resistant strains have been identified globally. The current treatment recommended by the World Health Organization is ceftriaxone and azithromycin dual therapy. However, resistance to azithromycin and ceftriaxone are increasing and treatment failures have been reported. As a result, there is a critical need to develop novel strategies for mitigating the spread of antimicrobial-resistant N. gonorrhoeae through improved diagnosis and treatment of resistant infections. Strategies that are currently being pursued include developing molecular assays to predict resistance, utilizing higher doses of ceftriaxone, repurposing older antibiotics, and developing newer agents. In addition, efforts to discover a vaccine for N. gonorrhoeae have been reignited in recent years with the cross-protectivity provided by the N. meningitidis vaccine, with several new strategies and targets. Despite the significant progress that has been made, there is still much work ahead to combat antimicrobial-resistant N. gonorrhoeae globally.

Developing a model to predict individualised treatment for gonorrhoea: a modelling study

OBJECTIVE

To develop a tool predicting individualised treatment for gonorrhoea, enabling treatment with previously recommended antibiotics, to reduce use of last-line treatment ceftriaxone.

DESIGN

A modelling study.

SETTING

England and Wales.

PARTICIPANTS

Individuals accessing sentinel health services.

INTERVENTION

Developing an Excel model which uses participants' demographic, behavioural and clinical characteristics to predict susceptibility to legacy antibiotics. Model parameters were calculated using data for 2015-2017 from the Gonococcal Resistance to Antimicrobials Surveillance Programme.

MAIN OUTCOME MEASURES

Estimated number of doses of ceftriaxone saved, and number of people delayed effective treatment, by model use in clinical practice. Model outputs are the predicted risk of resistance to ciprofloxacin, azithromycin, penicillin and cefixime, in groups of individuals with different combinations of characteristics (gender, sexual orientation, number of recent sexual partners, age, ethnicity), and a treatment recommendation.

RESULTS

Between 2015 and 2017, 8013 isolates were collected: 64% from men who have sex with men, 18% from heterosexual men and 18% from women. Across participant subgroups, stratified by all predictors, resistance prevalence was high for ciprofloxacin (range: 11%-51%) and penicillin (range: 6%-33%). Resistance prevalence for azithromycin and cefixime ranged from 0% to 13% and for ceftriaxone it was 0%. Simulating model use, 88% of individuals could be given cefixime and 10% azithromycin, saving 97% of ceftriaxone doses, with 1% of individuals delayed effective treatment.

CONCLUSIONS

Using demographic and behavioural characteristics, we could not reliably identify a participant subset in which ciprofloxacin or penicillin would be effective. Cefixime resistance was almost universally low; however, substituting ceftriaxone for near-uniform treatment with cefixime risks re-emergence of resistance to cefixime and ceftriaxone. Several subgroups had low azithromycin resistance, but widespread azithromycin monotherapy risks resistance at population level. However, this dataset had limitations; further exploration of individual characteristics to predict resistance to a wider range of legacy antibiotics may still be appropriate.

Neisseria gonorrhoeae Antimicrobial Resistance: Past to Present to Future

Neisseria gonorrhoeae (gonococcus) is a Gram-negative bacterium that causes gonorrhoea-a sexually transmitted disease. This gonococcus has progressively developed resistance to most of the available antimicrobials. Only a few countries around the world have been able to run extensive surveillance programmes on gonococcal infection and antimicrobial resistance, raising a global concern. Thus, this review focuses on the mechanisms of resistance to recommended antimicrobials in the past and present time. The approaches by the scientific community in the development of novel technologies such as whole-genome sequencing to predict antimicrobial resistance, track gonococcal transmission, as well as, introduce new therapeutics like Solithromycin, Zoliflodacin, and Gepotidacin were also discussed.

Comparison of solithromycin with erythromycin in Enterococcus faecalis and Enterococcus faecium from China: antibacterial activity, clonality, resistance mechanism, and inhibition of biofilm formation

Solithromycin (SOL), a fourth-generation macrolide and ketolide, has been reported to have robust antibacterial activity against a wide spectrum of Gram-positive bacteria. However, the impact of SOL on planktonic growth and biofilm formation of clinical enterococcus isolates remains unclear. In this study, 276 Enterococcus faecalis isolates and 122 Enterococcus faecium were retrospectively collected from a tertiary hospital from China. SOL against clinical isolates of enterococci from China were evaluated the antimicrobial activity in comparison with erythromycin, and explore its relationship with the clonality, virulence genes and resistance mechanism of these isolates. Our data showed that the MICs of SOL against clinical E. faecalis and E. faecium isolates from China were ≤4 and ≤8 mg l^-1, respectively. ST16 and ST179 were regarded as the risk factor to SOL resistance in E. faecalis. SOL could inhibit but not eradicate the biofilm formation of E. faecalis. The bactericidal effects of SOL against E. faecalis and E. faecium were demonstrated to be similar to linezolid and vancomycin using time-kill assays. In conclusion, SOL showed significantly enhanced antibacterial activity against clinical isolates of E. faecalis and E. faecium from China in comparison to erythromycin. Furthermore, SOL could inhibit the biofilm formation of E. faecalis and have the similar bactericidal ability as linezolid and vancomycin against both E. faecalis and E. faecium.

Gonorrhea in a Tertiary Care Portuguese Hospital: A 10-year Retrospective Study of the Evolution of Cases and Drug Resistance of the Isolates

BACKGROUND

Sexually Transmitted Infections remain a major public health concern worldwide. Although traditionally considered treatable, the emergence of Neisseria gonorrhoeae resistance to antimicrobials is currently a serious problem. The goal of this study was to evaluate the incidence and trends of antimicrobial resistance over the last 10 years in N. gonorrhoeae isolates from a Portuguese Centre.

METHODS

Laboratorial confirmed N. gonorrhoeae infections diagnosed between 2009 and 2018 were evaluated. Susceptibilities to penicillin, tetracycline, ciprofloxacin, azithromycin and cefotaxime were studied, along with demographic and clinical characteristics.

RESULTS

From 2009 to 2018, 440 cases of N. gonorrhoeae infection were diagnosed in our center, with a significant yearly increase (p<0.05). Most cases occurred in males (97.9%), with a median age of 25 years. In 88.7% of the cases, treatment with ceftriaxone plus azithromycin was used. Resistances to penicillin, tetracycline and ciprofloxacin remained high throughout the study period.

CONCLUSIONS

Antimicrobial resistance of N. gonorrhoeae appeared shortly after the introduction of antimicrobials. To combat this problem, improved surveillance and more studies combining susceptibility and epidemiological data are needed. In our population, N. gonorrhoeae remains highly susceptible to the antibiotics currently recommended for its treatment, whereas ciprofloxacin, azithromycin (in monotherapy) and penicillin should be avoided as empirical treatment.

[Social inequalities related to antimicrobial resistance in N. gonorrhoeae in ColombiaDesigualdades sociais relacionadas à resistência antimicrobiana de N. gonorrhoeae na Colômbia]

Objetivo.

Medir desigualdades sociales en la resistencia antimicrobiana de la Neisseria gonorrhoeae en Colombia.

Métodos.

Estudio ecológico utilizando un multipanel de datos desagregado a nivel subnacional de los aislamientos en la N. gonorrhoeae como proxy de resistencia antimicrobiana (RAM) entre 2009 y 2018. Se llevó a cabo una caracterización sociodemográfica, un análisis de la sensibilidad antimicrobiana de aislamientos de N. gonorrhoeae, y una medición de desigualdades en la RAM para la N. gonorrhoeae mediante el índice de desigualdad de la pendiente, el índice de desigualdad relativo y el índice de concentración.

Resultados.

Los hallazgos indican resistencia antimicrobiana de aislamientos de N. gonorrhoeae a penicilina (50,7%) y tetraciclina (67,3%); y la existencia de desigualdades absolutas y relativas durante el período analizado. Las barreras de acceso a servicios de salud, no haber recibido información de prevención de las infecciones de transmisión sexual, necesidades básicas insatisfechas y analfabetismo explicaron las desigualdades en la RAM de la N. gonorrhoeae.

Conclusiones.

Seis recomendaciones emergen para contener en gran medida la RAM en la N. gonorrhoeae: i) aumentar conciencia sobre la salud sexual y reproductiva segura; ii) repensar cómo entregar mensajes claves con enfoque de equidad; iii) mejorar los sistemas de información, prescripción y cadena de medicamentos; iv) crear coaliciones para mejorar la respuesta y compartir objetivos con el sector privado; v) mejorar la disponibilidad y desagregación de los datos; y vi) apoyar investigaciones en desigualdades en RAM.

Effect of vaccination on the use of antimicrobial agents: a systematic literature review

BACKGROUND

Antimicrobial resistance is a growing global health threat. To preserve the effectiveness of antimicrobials, it is important to reduce demand for antimicrobials.

OBJECTIVES

The objective of the study was to screen the existing peer-reviewed literature to identify articles that addressed the potential impact of influenza or Pneumococcus vaccination on antibiotic usage. Data sources: PubMed, Embase Study eligibility criteria: Clinical studies where antimicrobial prescribing was assessed in both vaccinated and unvaccinated populations. Participants and interventions: All patient populations were included (infants, children, adults and elderly), where the effects of the intervention (vaccination) was assessed.

RESULTS

We identified unique 3638 publications, of which 26 were judged to be of sufficiently high quality to allow the calculation of the potential impact of vaccination. Of these studies 23/26 found a significant reduction in antibiotic use by at least one of the parameters assessed.

LIMITATIONS

Different measures used to define anti-microbial use, studies typically focus on specific risk groups and most studies are from high-income countries. Conclusions and implications of key findings: Despite the limitations of the review, the evidence indicates that improved coverage with existing vaccines may significantly reduce antimicrobial demand. This suggests it may be a valuable tool for antimicrobial stewardship. Key messages While vaccines against a number of pathogens have been studied for their ability to reduce antimicrobial use, currently only vaccination against influenza or pneumococcus has generated sufficient data for analysis Vaccination against either influenza or pneumococcus significantly reduced overall antimicrobial prescribing rates, both in vaccinated individuals and at a population level Maintaining and expanding vaccination coverage thus appears to be a key tool for antimicrobial stewardship.

Pharmacokinetic/pharmacodynamic considerations for new and current therapeutic drugs for uncomplicated gonorrhoea-challenges and opportunities

BACKGROUND

Increasing multidrug resistance rates in Neisseria gonorrhoeae have raised concerns and an urgent call for new antibiotics for treatment of gonorrhoea. Several decades of subdued drug development in this field and the recent failures of two new antibiotics to show non-inferiority compared with the current first-line antibiotics ceftriaxone plus azithromycin highlight the need for improved preclinical tools to predict clinical outcome of new drugs in the development process.

OBJECTIVES

To summarize current pharmacokinetic/pharmacodynamic (PK/PD) knowledge and dose-finding strategies for antibiotics against gonorrhoea.

SOURCES

Literature review of published papers and discussions by global experts at a special workshop on this topic.

CONTENT

We review current knowledge of gonococcal specific PK/PD principles and provide an update on new in vitro and in vivo models to correlate drug exposure with clinical outcome, and identify challenges and gaps in gonococcal therapeutic research.

IMPLICATIONS

Identifying the ideal antimicrobial agent and dose for treating uncomplicated urogenital and pharyngeal gonococcal disease requires appropriate validated non-clinical PK/PD models. Recent advances in adapting in vitro and in vivo models for use in gonorrhoea are an important step for enabling the development of new drugs with reduced risk of failure in Phase 3 clinical development and diminish the risk of emergence of resistance.

Neisseria gonorrhoeae Infections

Gonorrhea is a sexually transmitted disease with a high morbidity burden. Despite having guidelines for its treatment, the incidence of the disease follows an increasing trend worldwide. This is mainly due to the appearance of antibiotic-resistant strains, inefficient diagnostic methods and poor sexual education. Without an effective vaccine available, the key priorities for the control of the disease include sexual education, contact notification, epidemiological surveillance, diagnosis and effective antibiotic treatment. This Special Issue focuses on some of these important issues such as the molecular mechanisms of the disease, diagnostic tests and different treatment strategies to combat gonorrhea.

Detection in the United Kingdom of the Neisseria gonorrhoeae FC428 clone, with ceftriaxone resistance and intermediate resistance to azithromycin, October to December 2018

We describe detection in the United Kingdom (UK) of the drug-resistant Neisseria gonorrhoeae FC428 clone, with ceftriaxone resistance and intermediate azithromycin resistance. Two female patients developed infection following contact with UK-resident men from the same sexual network linked to travel to Ibiza, Spain. One case failed treatment with ceftriaxone, and azithromycin and gentamicin, before successful treatment with ertapenem. Both isolates had indistinguishable whole-genome sequences. Urgent action is essential to contain this drug-resistant strain.

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.

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.

Efficacy and Safety of Injectable and Oral Antibiotics in Treating Gonorrhea: A Systematic Review and Network Meta-Analysis

Gonorrhea is the second most frequently reported sexually transmitted infectious disease of bacterial origin in the world. Current empiric therapies rely on broad-spectrum antibiotics. However, treatment options are becoming limited due to the rise of drug-resistant gonorrhea. To control the rise of drug-resistant gonorrhea and to identify alternative treatment options, clinicians will have to increasingly rely on experimental evidence for the treatment of gonorrhea patients. Thus, we performed a systematic review and network meta-analysis of all randomized clinical trials about the efficacy and safety of various antibiotic regimens in adults with gonorrhea. We searched all references in Embase and PubMed from the date of their inception to January 2019, and then an updated search was performed in March 2019. Of the 28,843 identified references, 44 fulfilled our selection criteria. We used a network meta-analysis based on a frequentist approach to evaluate the efficacy and safety of 12 injectable and 11 oral antibiotics. The efficacy of treatments was ranked by p score and inconsistency was assessed by a back-calculation method. Certainty of evidence was evaluated by the GRADE system. For injectable drugs, there was no difference in efficacy between a reference antibiotic and other drugs. However, ceftriaxone had significantly better efficacy than cefuroxime (OR, 12.03; 95% CI 3.73–38.79), cephaloridine (OR, 42.41; 95% CI 8.77–205.07), kanamycin (OR, 5.45; 95% CI 1.25–23.70), penicillin (OR, 13.11; 95% CI 4.48–38.37), and spectinomycin (OR, 4.70; 95% CI 1.62–13.62). Thus, ceftriaxone was the most effective injectable drug (p score of 0.924). As for oral drugs, azithromycin was the most effective compound (p score of 0.8633). There were no significant differences in safety between injectable and oral treatments. In our systematic review of randomized controlled trials, we found azithromycin and ceftriaxone to be the most effective antibiotics for the treatment of gonorrhea. This is in line with current guidelines which recommend a combination therapy of azithromycin and ceftriaxone for the treatment of gonorrhea due to increased antimicrobial resistance. Our analysis identified gentamicin and ofloxacin as alternative therapeutics to treat drug-resistant gonorrhea.

Multiresistant Neisseria gonorrhoeae: a new threat in second decade of the XXI century

Neisseria gonorrhoeae is an etiologic agent of gonorrhoea, one of the most common sexually transmitted diseases caused by bacteria. For many years, infections caused by N. gonorrhoeae were considered to be relatively easy to treat; however, resistance has emerged successively to all therapeutic agents used in treatment of the disease, e.g., penicillin, ciprofloxacin or azithromycin. Currently, the global problem is the emergence and a threat of spread of N. gonorrhoeae strains resistant to extended-spectrum cephalosporins (ESC), such as injectable ceftriaxone and oral-used cefixime. Especially, dangerous are multi-resistant strains resistant simultaneously to ESC and azithromycin. Three strains with high-level resistance to azithromycin and resistant to ESC were first time isolated in 2018. Moreover, in 2018, the first ESBL was described in N. gonorrhoeae and that makes the threat of appearing the ESBL mechanism of resistance in N. gonorrhoeae more real, even though the strain was sensitive to ceftriaxone. Molecular typing revealed that variants resistant to ESC occurred also among strains belonging to epidemic clonal complex CC1 (genogroup G1407) distinguished in NG-MAST typing system. The G1407 genogroup, in particular the ST1407 sequence type, is currently dominant in most European countries. The presence of different mechanisms of drug resistance significantly affects clinical practice and force changes in treatment regimens and introduction of new drugs.

Epidemiology of Treponema pallidum, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and herpes simplex virus type 2 among female sex workers in the Middle East and North Africa: systematic review and meta-analytics

BACKGROUND

The epidemiology of sexually transmitted infections (STIs) and the role of commercial heterosexual sex networks in driving STI transmission in the Middle East and North Africa (MENA) region remain largely unknown.

OBJECTIVE

To characterize the epidemiology of Treponema pallidum (syphilis), Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and herpes simplex virus type 2 (HSV-2) among female sex workers (FSWs) in MENA using an in-depth quantitative assessment.

METHODS

A systematic review on ten international, regional, and country-level databases was conducted, and reported following PRISMA guidelines. Pooled prevalences of current and/or ever infection for each STI were estimated using random-effects meta-analyses. Sources of between-study heterogeneity were investigated through random-effects meta-regressions.

RESULTS

One T. pallidum incidence study and 144 STI prevalence studies were identified for 45 812 FSWs in 13 MENA countries. The pooled prevalence of current infection was 12.7% (95% confidence interval (CI) = 8.5%-17.7%) for T. pallidum, 14.4% (95% CI = 8.2%-22.0%) for C. trachomatis, 5.7% (95% CI = 3.5%-8.4%) for N. gonorrhoeae, and 7.1% (95% CI = 4.3%-10.5%) for T. vaginalis. The pooled prevalence of ever infection (seropositivity using antibody testing) was 12.8% (95% CI = 9.4%-16.6%) for T. pallidum, 80.3% (95% CI = 53.2%-97.6%) for C. trachomatis, and 23.7% (95% CI = 10.2%-40.4%) for HSV-2. The multivariable meta-regression for T. pallidum infection demonstrated strong subregional differences, with the Horn of Africa and North Africa showing, respectively 6-fold (adjusted odds ratio (AOR): 6.4; 95% CI = 2.5-16.7) and 5-fold (AOR = 5.0; 95% CI = 2.5-10.6) higher odds of infection than Eastern MENA. There was also strong evidence for declining T. pallidum odds of infection at 7% per year (AOR = 0.93; 95% CI = 0.88-0.98). Study-specific factors including diagnostic method, sample size, sampling methodology, and response rate, were not associated with syphilis infection. The multivariable model explained 48.5% of the variation in T. pallidum prevalence.

CONCLUSIONS

STI infection levels among FSWs in MENA are considerable, supporting a key role for commercial heterosexual sex networks in transmission dynamics, and highlighting the health needs of this neglected and vulnerable population. Syphilis prevalence in FSWs appears to have been declining for at least three decades. Gaps in evidence persist for multiple countries.

Impact of Species Diversity on the Design of RNA-Based Diagnostics for Antibiotic Resistance in Neisseria gonorrhoeae

Quantitative assessment of antibiotic-responsive RNA transcripts holds promise for a rapid point-of-care (POC) diagnostic tool for antimicrobial susceptibility testing. These assays aim to distinguish susceptible and resistant isolates by transcriptional differences upon drug exposure. However, an often-overlooked dimension of designing these tests is that the genetic diversity within a species may yield differential transcriptional regulation independent of resistance phenotype. Here, we use a phylogenetically diverse panel of Neisseria gonorrhoeae and transcriptome profiling coupled with reverse transcription-quantitative PCR to test this hypothesis, to identify azithromycin responsive transcripts and evaluate their potential diagnostic value, and to evaluate previously reported diagnostic markers for ciprofloxacin resistance (porB and rpmB). Transcriptome profiling confirmed evidence of genetic distance and population structure impacting transcriptional response to azithromycin. Taking this into account, we found azithromycin-responsive transcripts overrepresented in susceptible strains compared to resistant strains and selected four candidate diagnostic transcripts (rpsO, rplN, omp3, and NGO1079) that were the most significantly differentially regulated between phenotypes across drug exposure. RNA signatures for these markers categorically predicted resistance in 19/20 cases, with the one incorrect categorical assignment for an isolate at the threshold of reduced susceptibility. Finally, we found that porB and rpmB expression were not uniformly diagnostic of ciprofloxacin resistance in a panel of isolates with unbiased phylogenetic sampling. Overall, our results suggest that RNA signatures as a diagnostic tool are promising for future POC diagnostics; however, development and testing should consider representative genetic diversity of the target pathogen.

Mycobacterial Aminoglycoside Acetyltransferases: A Little of Drug Resistance, and a Lot of Other Roles

Aminoglycoside acetyltransferases are important determinants of resistance to aminoglycoside antibiotics in most bacterial genera. In mycobacteria, however, aminoglycoside acetyltransferases contribute only partially to aminoglycoside susceptibility since they are related with low level resistance to these antibiotics (while high level aminoglycoside resistance is due to mutations in the ribosome). Instead, aminoglycoside acetyltransferases contribute to other bacterial functions, and this can explain its widespread presence along species of genus Mycobacterium. This review is focused on two mycobacterial aminoglycoside acetyltransferase enzymes. First, the aminoglycoside 2'-N-acetyltransferase [AAC(2')], which was identified as a determinant of weak aminoglycoside resistance in M. fortuitum, and later found to be widespread in most mycobacterial species; AAC(2') enzymes have been associated with resistance to cell wall degradative enzymes, and bactericidal mode of action of aminoglycosides. Second, the Eis aminoglycoside acetyltransferase, which was identified originally as a virulence determinant in M. tuberculosis (enhanced intracellular survival); Eis protein in fact controls production of pro-inflammatory cytokines and other pathways. The relation of Eis with aminoglycoside susceptibility was found after the years, and reaches clinical significance only in M. tuberculosis isolates resistant to the second-line drug kanamycin. Given the role of AAC(2') and Eis proteins in mycobacterial biology, inhibitory molecules have been identified, more abundantly in case of Eis. In conclusion, AAC(2') and Eis have evolved from a marginal role as potential drug resistance mechanisms into a promising future as drug targets.