Antibiotic-resistant Neisseria Gonorrhoeae Research Articles

Neisseria gonorrhoeae Antimicrobial Resistance: The Future of Antibiotic Therapy.

The growing threat of antibiotic-resistant Neisseria gonorrhoeae, which causes gonorrhea, presents a current public health challenge. Over the years, the pathogen has developed resistance to different antibiotics, leaving few effective treatment options. High-level resistance to key drugs, including ceftriaxone, has become a concerning reality. This article primarily focuses on the treatment of gonorrhea and the current clinical trials aimed at providing new antibiotic treatment options. We explore ongoing efforts to assess new antibiotics, including zoliflodacin, and gepotidacin. These drugs offer new effective treatment options, but their rapid availability remains uncertain. We delve into two ongoing clinical trials: one evaluating the efficacy and safety of gepotidacin compared to the standard ceftriaxone-azithromycin combination and the other assessing the non-inferiority of zoliflodacin versus the combination therapy of ceftriaxone-azithromycin. These trials represent crucial steps in the search for alternative treatments for uncomplicated gonorrhea. Notably, gonorrhea has been included in the "WHO Priority Pathogens List for Research and Development of New Antibiotics". In conclusion, the urgent need for innovative treatment strategies is underscored by the rising threat of antibiotic resistance in N. gonorrhoeae; collaboration among researchers, industries, and healthcare authorities is therefore essential.

Evolutionarily conserved heat shock protein, HtpX, as an adjunct target against antibiotic-resistant Neisseria gonorrhoeae.

The emergence of multiple drug resistance and extreme drug resistance pathogens necessitates the continuous evaluation of the pathogenic genome to identify conserved molecular targets and their respective inhibitors. In this study, we mapped the global mutational landscape of Neisseria gonorrhoeae (an intracellular pathogen notoriously known to cause the sexually transmitted disease gonorrhoea). We identified highly variable amino acid positions in the antibiotic target genes like the penA, ponA, 23s rRNA, rpoB, gyrA, parC, mtrR and porB. Some variations are directly reported to confer resistance to the currently used front-line drugs like ceftriaxone, cefixime, azithromycinand ciprofloxacin. Further, by whole genome comparison and Shannon entropy analysis, we identified a completely conserved protein HtpX in the drug-resistant as well as susceptible isolates of N. gonorrhoeae (NgHtpX). Comparison with the only available information of Escherichia coli HtpX suggested it to be a transmembrane metalloprotease having a role in stress response. The critical zinc-binding residue of NgHtpX was mapped to E141. By applying composite high throughput screening followed by MD simulations, we identified pemirolast and thalidomide as high-energy binding ligands of NgHtpX. Following cloning and expression of the purified metal-binding domain of NgHtpX (NgHtpXd), its Zn2+ -binding (Kd = 0.4 µM) and drug-binding (pemirolast, Kd = 3.47 µM; and thalidomide, Kd = 1.04 µM) potentials were determined using in-vitro fluorescence quenching experiment. When tested on N. gonorrhoeae cultures, both the ligands imposed a dose-dependent reduction in viability. Overall, our results provide high entropy positions in the targets of presently used antibiotics, which can be further explored to understand the AMR mechanism. Additionally, HtpX and its specific inhibitors identified can be utilised effectively in managing gonococcal infections.

Reverse vaccinology approaches to introduce promising immunogenic and drug targets against antibiotic-resistant Neisseria gonorrhoeae: Thinking outside the box in current prevention and treatment.

Gonorrhea is an urgent antimicrobial resistance threat and its therapeutic options are continuously getting restricted. Moreover, no vaccine has been approved against it so far. Hence, the present study aimed to introduce novel immunogenic and drug targets against antibiotic-resistant Neisseria gonorrhoeae strains. In the first step, the core proteins of 79 complete genomes of N. gonorrhoeae were retrieved. Next, the surface-exposed proteins were evaluated from different aspects such as antigenicity, allergenicity, conservancy, and B-cell and T-cell epitopes to introduce promising immunogenic candidates. Then, the interactions with human Toll-like receptors (TLR-1, 2, and 4), and immunoreactivity to elicit humoral and cellular immune responses were simulated. On the other hand, to identify novel broad-spectrum drug targets, the cytoplasmic and essential proteins were detected. Then, the N. gonorrhoeae metabolome-specific proteins were compared to the drug targets of the DrugBank, and novel drug targets were retrieved. Finally, the protein data bank (PDB) file availability and prevalence among the ESKAPE group and common sexually transmitted infection (STI) agents were assessed. Our analyses resulted in the recognition of ten novel and putative immunogenic targets including murein transglycosylase A, PBP1A, Opa, NlpD, Azurin, MtrE, RmpM, LptD, NspA, and TamA. Moreover, four potential and broad-spectrum drug targets were identified including UMP kinase, GlyQ, HU family DNA-binding protein, and IF-1. Some of the shortlisted immunogenic and drug targets have confirmed roles in adhesion, immune evasion, and antibiotic resistance that can induce bactericidal antibodies. Other immunogenic and drug targets might be associated with the virulence of N. gonorrhoeae as well. Thus, further experimental studies and site-directed mutations are recommended to investigate the role of potential vaccine and drug targets in the pathogenesis of N. gonorrhoeae. It seems that the efforts for proposing novel vaccines and drug targets appear to be pavingthe way for a prevention-treatment strategy against this bacterium. Additionally, a combination of bactericidal monoclonal antibodies and antibiotics is a promising approach to curing N. gonorrhoeae.

In-silico investigation of a novel inhibitors against the antibiotic-resistant Neisseria gonorrhoeae bacteria

Antibiotics are drugs that are used to treat or prevent bacterial infections. They work by either killing or stopping bacteria from spreading. Nevertheless, it appeared in the last decade, Antibiotic-resistant bacteria are bacteria resistant to antibiotics and cannot be controlled or killed by them. In the presence of an antibiotic, they can live and even reproduce. The Neisseria gonorrhoeae bacteria is appearing to be a multidrug-resistant pathogen. Many factors contribute to antibiotic resistance, including unfettered access to antimicrobials, incorrect drug selection, misuse, and low-quality antibiotics. Here, we investigated in-silico docking screening and analysis for ten natural marine fungus extracted compounds. The resulted data were examined for the best binding affinity, toxicity, and chemical interactions. The most superior compound was elipyrone A with six hydrogen bonds, −8.5 of binding affinity, and preferable results in the SWISS-ADME examination. It is well known that “Declining corporate investment and a lack of innovation in the development of new antibiotics are weakening efforts to battle drug-resistant illnesses,” according to the World Health Organization (WHO). So, we extended our effort to predict a new natural compound to overcome the resistance of this bacteria.

Ribonucleotide reductase, a novel drug target for gonorrhea.

Antibiotic-resistant Neisseria gonorrhoeae (Ng) are an emerging public health threat due to increasing numbers of multidrug resistant (MDR) organisms. We identified two novel orally active inhibitors, PTC-847 and PTC-672, that exhibit a narrow spectrum of activity against Ng including MDR isolates. By selecting organisms resistant to the novel inhibitors and sequencing their genomes, we identified a new therapeutic target, the class Ia ribonucleotide reductase (RNR). Resistance mutations in Ng map to the N-terminal cone domain of the α subunit, which we show here is involved in forming an inhibited α4β4 state in the presence of the β subunit and allosteric effector dATP. Enzyme assays confirm that PTC-847 and PTC-672 inhibit Ng RNR and reveal that allosteric effector dATP potentiates the inhibitory effect. Oral administration of PTC-672 reduces Ng infection in a mouse model and may have therapeutic potential for treatment of Ng that is resistant to current drugs.

Strengthening the US Response to Resistant Gonorrhea: An Overview of a Multisite Program to Enhance Local Response Capacity for Antibiotic-Resistant Neisseria gonorrhoeae.

In 2016, Centers for Disease Control and Prevention initiated Strengthening the US Response to Resistant Gonorrhea (SURRG) in multiple jurisdictions to enhance antibiotic resistant gonorrhea rapid detection and response infrastructure and evaluate the impact of key strategies. Eight jurisdictions were funded to establish or enhance local gonococcal culture specimen collection in sexually transmitted disease and community clinics, conduct rapid antimicrobial susceptibility testing (AST) in local laboratories, modify systems for enhanced data collection and rapid communication of results, and initiate enhanced partner services among patients with gonorrhea demonstrating elevated minimum inhibitory concentrations (MICs) to ceftriaxone, cefixime or azithromycin. Grantees incorporated genital, pharyngeal, and rectal gonococcal culture collection from all genders at participating clinics. During 2018 to 2019, grantees collected 58,441 culture specimens from 46,822 patients and performed AST on 10,814 isolates (representing 6.8% [3412] and 8.9% [4883] of local reported cases in 2018 and 2019, respectively). Of isolates that underwent AST, 11% demonstrated elevated azithromycin MICs; fewer than 0.5% demonstrated elevated ceftriaxone or cefixime MICs. Among patients whose infections demonstrated elevated MICs, 81.7% were interviewed for partner elicitation; however, limited new cases were identified among partners and contacts. As a public health model to build capacity to slow the spread of emerging resistance, SURRG successfully expanded culture collection, implemented rapid AST, and implemented an enhanced partner services investigation approach in participating jurisdictions. Findings from SURRG may enhance preparedness efforts and inform a longer-term, comprehensive, and evidence-based public health response to emerging gonococcal resistance. Continued development of innovative approaches to address emerging resistance is needed.

Expanding U.S. Laboratory Capacity for Neisseria gonorrhoeae Antimicrobial Susceptibility Testing and Whole-Genome Sequencing through the CDC's Antibiotic Resistance Laboratory Network.

U.S. gonorrhea rates are rising, and antibiotic-resistant Neisseria gonorrhoeae (AR-Ng) is an urgent public health threat. Since implementation of nucleic acid amplification tests for N. gonorrhoeae identification, the capacity for culturing N. gonorrhoeae in the United States has declined, along with the ability to perform culture-based antimicrobial susceptibility testing (AST). Yet AST is critical for detecting and monitoring AR-Ng. In 2016, the CDC established the Antibiotic Resistance Laboratory Network (AR Lab Network) to shore up the national capacity for detecting several resistance threats including N. gonorrhoeae AR-Ng testing, a subactivity of the CDC's AR Lab Network, is performed in a tiered network of approximately 35 local laboratories, four regional laboratories (state public health laboratories in Maryland, Tennessee, Texas, and Washington), and the CDC's national reference laboratory. Local laboratories receive specimens from approximately 60 clinics associated with the Gonococcal Isolate Surveillance Project (GISP), enhanced GISP (eGISP), and the program Strengthening the U.S. Response to Resistant Gonorrhea (SURRG). They isolate and ship up to 20,000 isolates to regional laboratories for culture-based agar dilution AST with seven antibiotics and for whole-genome sequencing of up to 5,000 isolates. The CDC further examines concerning isolates and monitors genetic AR markers. During 2017 and 2018, the network tested 8,214 and 8,628 N. gonorrhoeae isolates, respectively, and the CDC received 531 and 646 concerning isolates and 605 and 3,159 sequences, respectively. In summary, the AR Lab Network supported the laboratory capacity for N. gonorrhoeae AST and associated genetic marker detection, expanding preexisting notification and analysis systems for resistance detection. Continued, robust AST and genomic capacity can help inform national public health monitoring and intervention.

Feasibility of Using a Luminescence-Based Method to Determine Serum Bactericidal Activity against Neisseria gonorrhoeae.

Development of a vaccine to limit the impact of antibiotic resistant Neisseria gonorrhoeae is now a global priority. Serum bactericidal antibody (SBA) is a possible indicator of protective immunity to N. gonorrhoeae, but conventional assays measure colony forming units (CFU), which is time-consuming. A luminescent assay that quantifies ATP as a surrogate measure of bacterial viability was tested on N. gonorrhoeae strains FA1090, MS11 and P9-17 and compared to CFU-based readouts. There was a linear relationship between CFU and ATP levels for all three strains (r > 0.9). Normal human serum (NHS) is a common source of complement for SBA assays, but needs to be screened for non-specific bactericidal activity. NHS from 10 individuals were used for serum sensitivity assays—sensitivity values were significantly reduced with the ATP method for FA1090 (5/10, p < 0.05) and MS11 (10/10, p < 0.05), whereas P9-17 data were comparable for all donors. Our results suggest that measuring ATP underestimates serum sensitivity of N. gonorrhoeae and that the CFU method is a better approach. However, mouse anti-P9-17 outer membrane vesicles (OMV) SBA titres to P9-17 were comparable with both methods (r = 0.97), suggesting this assay can be used to rapidly screen sera for bactericidal antibodies to gonococci.

Development of New Antimicrobials for Urogenital Gonorrhea Therapy: Clinical Trial Design Considerations.

Gonorrhea remains a major public health challenge, and current recommendations for gonorrhea treatment are threatened by evolving antimicrobial resistance and a diminished pipeline for new antibiotics. Evaluations of potential new treatments for gonorrhea currently make limited use of new understanding of the pharmacokinetic and pharmacodynamic contributors to effective therapy, the prevention of antimicrobial resistance, and newer designs for clinical trials. They are hampered by the requirement to utilize combination ceftriaxone/azithromycin therapy as the comparator regimen in noninferiority trials designed to seek an indication for gonorrhea therapy. Evolving gonococcal epidemiology and clinical trial design constraints hinder the enrollment of those populations at the greatest risk for gonorrhea (adolescents, women, and persons infected with antibiotic-resistant Neisseria gonorrhoeae). This article summarizes a recent meeting on the evaluation process for antimicrobials for urogenital gonorrhea treatment and encourages the consideration of new designs for the evaluation of gonorrhea therapy.

For Gonorrhea, Gentamicin Was Less Effective Than Ceftriaxone

Rapid development of antibiotic-resistant Neisseria gonorrhoeae hampers effective control efforts (the current recommended therapy is a single 500-mg

Quantitative Examination of Antibiotic Susceptibility of Neisseria gonorrhoeae Aggregates Using ATP-utilization Commercial Assays and Live/Dead Staining.

The emergence of antibiotic resistant Neisseria gonorrhoeae (GC) is a worldwide health threat and highlights the need to identify individuals who fail treatment. This Gram-negative bacterium causes gonorrhea exclusively in humans. During infection, it is able to form aggregates and/or biofilms. The minimum inhibitory concentration (MIC) test is used for to determine susceptibility to antibiotics and to define appropriate treatment. However, the mechanism of the eradication in vivo and its relationship to laboratory results are not known. A method that examines how GC aggregation affects antibiotic susceptibility and shows the relationship between aggregate size and antibiotic susceptibility was developed. When GC aggregate, they are more resistant to antibiotic killing, with bacteria in the center surviving ceftriaxone treatment better than those in the periphery. The data indicate that N. gonorrhoeae aggregation can reduce its susceptibility to ceftriaxone, which is not reflected using the standard agar plate-based MIC methods. The method used in this study will allow researchers to test bacterial susceptibility under clinically relevant conditions.

Molecular screening for Neisseria gonorrhoeae antimicrobial resistance markers in Nigerian men who have sex with men and transgender women.

Antimicrobial-resistant Neisseria gonorrhoeae (NG) is a global public health issue that threatens effectiveness of current treatments of NG. Increased use of nucleic acid amplification tests (NAATs) in lieu of cultures makes obtaining clinical isolates for susceptibility testing difficult and samples collected in commercial transport buffer for NAATs do not preserve viable organism, while molecular methods of assessing antibiotic susceptibility do not require viable organism. We evaluated 243 NG-positive samples in Aptima transport media including urine, oral, and rectal swabs from Nigerian men who have sex with men for markers to penicillinase-producing NG, ciprofloxacin ( GyrA and ParC mutations), and extended spectrum cephalosporins (ESCs, PenA mosaic [allele X], PonA, mtrR, PorB mutations) by real-time PCR. NG DNA was recovered in 75% (183/243) of samples. Of these, 93% (171/183) were positive for at least one resistance marker. We observed a prevalence of dual resistance markers to penicillin and ciprofloxacin at 46.2% (79/171). Six percent of samples (10/171) tested positive for the PenA mosaic (allele X) ESC marker. These data indicate that antibiotic-resistant NG is common in Nigeria. Laboratory and clinical capacity building in Nigeria should include development of methods to culture NG and determine antimicrobial susceptibility.

Detection of alarming increase in antibiotic resistant neisseria gonorrhoeae isolates in karaj, Iran

Detection of alarming increase in antibiotic resistant neisseria gonorrhoeae isolates in karaj, Iran

Risk factors for antimicrobial-resistant Neisseria gonorrhoeae and characteristics of patients infected with gonorrhea

BackgroundThere are very few data available regarding risk factors associated with antibiotic resistant-Neisseria gonorrhoeae. MethodsA study was conducted on 110 samples from 101 patients with gonococcal infection, in order to describe their characteristics and compare them with the antimicrobial susceptibility profile of their samples. ResultsAn association was observed between resistant infections and heterosexual men, older age, concurrent sexually transmitted infection, and unsafe sexual behaviors. ConclusionThere is a need for improved data on the risk factors associated with antibiotic resistant gonococcal infection in order to identify risk groups, and to propose public health strategies to control this infection.

Risk factors for antimicrobial-resistant Neisseria gonorrhoeae and characteristics of patients infected with gonorrhea

BackgroundThere are very few data available regarding risk factors associated with antibiotic resistant-Neisseria gonorrhoeae. MethodsA study was conducted on 110 samples from 101 patients with gonococcal infection, in order to describe their characteristics and compare them with the antimicrobial susceptibility profile of their samples. ResultsAn association was observed between resistant infections and heterosexual men, older age, concurrent sexually transmitted infection, and unsafe sexual behaviors. ConclusionThere is a need for improved data on the risk factors associated with antibiotic resistant gonococcal infection in order to identify risk groups, and to propose public health strategies to control this infection.

Whole-genome sequencing to determine transmission of Neisseria gonorrhoeae: an observational study

New approaches are urgently required to address increasing rates of gonorrhoea and the emergence and global spread of antibiotic-resistant Neisseria gonorrhoeae. We used whole-genome sequencing to study transmission and track resistance in N gonorrhoeae isolates. We did whole-genome sequencing of isolates obtained from samples collected from patients attending sexual health services in Brighton, UK, between Jan 1, 2011, and March 9, 2015. We also included isolates from other UK locations, historical isolates from Brighton, and previous data from a US study. Samples from symptomatic patients and asymptomatic sexual health screening underwent nucleic acid amplification testing; positive samples and all samples from symptomatic patients were cultured for N gonorrhoeae, and resulting isolates were whole-genome sequenced. Cefixime susceptibility testing was done in selected isolates by agar incorporation, and we used sequence data to determine multi-antigen sequence types and penA genotypes. We derived a transmission nomogram to determine the plausibility of direct or indirect transmission between any two cases depending on the time between samples: estimated mutation rates, plus diversity noted within patients across anatomical sites and probable transmission pairs, were used to fit a coalescent model to determine the number of single nucleotide polymorphisms expected. 1407 (98%) of 1437 Brighton isolates between Jan 1, 2011, and March 9, 2015 were successfully sequenced. We identified 1061 infections from 907 patients. 281 (26%) of these infections were indistinguishable (ie, differed by zero single nucleotide polymorphisms) from one or more previous cases, and 786 (74%) had evidence of a sampled direct or indirect Brighton source. We observed multiple related samples across geographical locations. Of 1273 infections in Brighton (including historical data), 225 (18%) were linked to another case elsewhere in the UK, and 115 (9%) to a case in the USA. Four lineages initially identified in Brighton could be linked to 70 USA sequences, including 61 from a lineage carrying the mosaic penA XXXIV allele, which is associated with reduced cefixime susceptibility. We present a whole-genome-sequencing-based tool for genomic contact tracing of N gonorrhoeae and demonstrate local, national, and international transmission. Whole-genome sequencing can be applied across geographical boundaries to investigate gonorrhoea transmission and to track antimicrobial resistance. Oxford National Institute for Health Research Health Protection Research Unit and Biomedical Research Centre.

Two decades of the gonococcal antimicrobial surveillance program in South America and the Caribbean: challenges and opportunities

ObjectivesThe WHO has called for a global action plan to control the spread and impact of antibiotic resistant Neisseria gonorrhoeae. We report on key antimicrobial susceptibility (AMS) trends in countries...

Non-cytotoxic nanomaterials enhance antimicrobial activities of cefmetazole against multidrug-resistant Neisseria gonorrhoeae.

The emergence and spread of antibiotic-resistant Neisseria gonorrhoeae has led to difficulties in treating patients, and novel strategies to prevent and treat this infection are urgently needed. Here, we examined 21 different nanomaterials for their potential activity against N. gonorrhoeae (ATCC 49226). Silver nanoparticles (Ag NPs, 120 nm) showed the greatest potency for reducing N. gonorrhoeae colony formation (MIC: 12.5 µg/ml) and possessed the dominant influence on the antibacterial activity with their properties of the nanoparticles within a concentration range that did not induce cytotoxicity in human fibroblasts or epithelial cells. Electron microscopy revealed that the Ag NPs significantly reduced bacterial cell membrane integrity. Furthermore, the use of clinical isolates of multidrug-resistant N. gonorrhoeae showed that combined treatment with 120 nm Ag NPs and cefmetazole produced additive effects. This is the first report to screen the effectiveness of nanomaterials against N. gonorrhoeae, and our results indicate that 120 nm Ag NPs deliver low levels of toxicity to human epithelial cells and could be used as an adjuvant with antibiotic therapy, either for topical use or as a coating for biomaterials, to prevent or treat multidrug-resistant N. gonorrhoeae.

Reply to “Management of Pharyngeal Gonorrhea Is Crucial To Prevent the Emergence and Spread of Antibiotic-Resistant Neisseria gonorrhoeae”

We are very grateful to Dr. Takashi Deguchi et al. for their positive response on our paper “High-Level Cefixime- and Ceftriaxone-Resistant N. gonorrhoeae in France: Novel penA Mosaic Allele in a Successful International Clone Causes Treatment Failure” ([10][1]). Dr. Deguchi, et al. emphasize

Mapping antibiotic-resistant Neisseria gonorrhoeae isolates in Metropolitan Toronto: Issues of scale, positional accuracy and confidentiality.

The primary objective of this paper was to investigate the methodological implications of mapping Neisseria gonorrhoeae using the partial three-digit postal code instead of the complete six-digit postal code. The reporting locations of N gonorrhoeae isolates submitted from hospitals, doctor's offices, private and provincial laboratories, and sexually transmitted disease (STD) clinics were used as a model. Specifically, the paper focused on variations in geographical distributions of STD data when mapped at different aggregations of postal code data and at different map scales. Such variations are of importance to those who analyze the spatial epidemiology of STDs, and the accessibility and use of health care services. This analysis showed that three-digit postal codes are useful in summarizing overall geographic distributions, but greatly reduce positional accuracy, which can lead to inaccurate delineation of service areas and populations served. The six-digit postal code is more appropriate for detailed analysis addressing behavioural issues. The analysis demonstrated that six-digits can be used without breaching individual confidentiality.