2018 UK national guideline for the management of infection with Neisseria gonorrhoeae

Use of a five-category partner-type classification within a chlamydia and gonorrhoea service evaluation highlights opportunities for targeted partner notification to improve STI control

OBJECTIVES

Partner notification (PN) is a key component of sexually transmitted infection control. British Association for Sexual Health and HIV guidelines now recommend partner-centred PN outcomes using a five-category partner classification (established, new, occasional, one-off, sex worker). We evaluated the reporting of partner-centred PN outcomes in two contrasting UK sexual health services.

METHODS

Using the electronic patient records of 40 patients with a positive gonorrhoea test and 180 patients with a positive chlamydia test, we extracted PN outcomes for the five most recent sexual contacts within the appropriate lookback period.

RESULTS

180 patients with chlamydia reported 262 partners: 220 were contactable (103 established, 9 new, 43 occasional, 52 one-off, 13 unknown/unrecorded). 40 patients with gonorrhoea reported 88 partners: 53 were contactable (7 established, 1 new, 14 occasional, 10 one-off and 21 unknown/not recorded). No sex worker partners were reported. Most established partners of people with chlamydia (96/103) or gonorrhoea (7/7) were notified but fewer (60/103 and 6/7, respectively) attended for testing. Of those, 39 had a positive chlamydia test and two had a positive gonorrhoea test. For both chlamydia and gonorrhoea, most occasional and new partners were reported to be notified but there was a sharper decline in those tested. For both infections, one-off partners had the lowest rates of accessing services and testing. For chlamydia, 81% were notified (42/52), 23% accessed services (12/52) and 21% tested (11/52). However, 91% of those tested were positive (10/11). The number of contactable one-off gonorrhoea contacts was small and few attended.

CONCLUSIONS

Measuring partner-centred PN outcomes was feasible. There were differences in partner engagement with PN between the different infections and partner types. If these findings are replicated in larger samples, it suggests that interventions to target one-off partners who have low rates of PN engagement yet high levels of positivity could play a key role in reducing infection at population level.

Antimicrobial Resistance in Curable Sexually Transmitted Infections

PURPOSE OF REVIEW

Antimicrobial resistance in sexually transmitted infections (STIs) has become an urgent global public health threat, raising the specter of untreatable infections. This review summarizes the determinants of resistance among the five most common curable STIs Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Treponema pallidum, and Trichomonas vaginalis, as well as strategies to mitigate the spread of resistance.

RECENT FINDINGS

Genetic mutations are key drivers of resistance for N. gonorrhoeae and M. genitalium. Resistance in T. vaginalis can also occur because of genetic mutations, yet differential regulation of genes critical in antibiotic metabolism as well as co-infection with organisms that inactivate therapy play important roles. While resistance in C. trachomatis and T. pallidum has not been a substantial clinical concern, resistance selection via the continued widespread use of antimicrobials remains possible. While resistance determinants are diverse and differ by pathogen, the strategies required to mitigate the continued emergence of resistance are similar: prevention of infection and treatment diversification. Underpinning those strategies, surveillance remains essential for monitoring and responding to the threat of drug-resistant infections.

German evidence- and consensus-based guideline on the management of penile urethritis

Urethritis is a common condition predominantly caused by sexually transmitted pathogens such as Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium. It is not possible to differentiate with certainty between pathogens on the basis of clinical characteristics alone. However, empirical antibiotic therapy is often initiated in clinical practice. The aim of this clinical practice guideline is to promote an evidence-based syndrome-orientated approach to the management of male adolescents and adults with symptoms of urethritis. Besides recommendations for the diagnosis, classification and choice of treatment, this guideline provides recommendations for the indication to empirically treat patients with penile urethritis. A novel feature compared to existing, pathogen-specific guidelines is the inclusion of a flowchart for the syndrome-orientated practical management. For suspected gonococcal urethritis requiring empirical treatment, ceftriaxone is recommended. Due to the risk of Chlamydia trachomatis co-infection, doxycycline should also be prescribed, unless follow-up for the treatment of possible co-infections is assured. For suspected non-gonococcal urethritis, doxycycline is the recommended empirical treatment. In the empiric treatment of both gonococcal and non-gonococcal penile urethritis, azithromycin is reserved for cases where doxycycline is contraindicated. This guideline also includes detailed recommendations on differential diagnosis, pathogen-specific treatments and specific situations, as well as patient counselling and follow-up.

Exploring SNP filtering strategies: the influence of strict vs soft core

Phylogenetic analyses are crucial for understanding microbial evolution and infectious disease transmission. Bacterial phylogenies are often inferred from SNP alignments, with SNPs as the fundamental signal within these data. SNP alignments can be reduced to a 'strict core' by removing those sites that do not have data present in every sample. However, as sample size and genome diversity increase, a strict core can shrink markedly, discarding potentially informative data. Here, we propose and provide evidence to support the use of a 'soft core' that tolerates some missing data, preserving more information for phylogenetic analysis. Using large datasets of Neisseria gonorrhoeae and Salmonella enterica serovar Typhi, we assess different core thresholds. Our results show that strict cores can drastically reduce informative sites compared to soft cores. In a 10 000-genome alignment of Salmonella enterica serovar Typhi, a 95% soft core yielded ten times more informative sites than a 100% strict core. Similar patterns were observed in N. gonorrhoeae. We further evaluated the accuracy of phylogenies built from strict- and soft-core alignments using datasets with strong temporal signals. Soft-core alignments generally outperformed strict cores in producing trees displaying clock-like behaviour; for instance, the N. gonorrhoeae 95% soft-core phylogeny had a root-to-tip regression R 2 of 0.50 compared to 0.21 for the strict-core phylogeny. This study suggests that soft-core strategies are preferable for large, diverse microbial datasets. To facilitate this, we developed Core-SNP-filter (https://github.com/rrwick/Core-SNP-filter), an open-source software tool for generating soft-core alignments from whole-genome alignments based on user-defined thresholds.

[Translated article] AEDVAEDV Expert Recommendations on the Management of Suppurative Sexually Transmitted Infections

The incidence of sexually transmitted infections (STIs) is increasing in Spain. Suppurative STIs are one of the most frequent reasons for consultation in specialized centers. The reason for suppurative STIs is multiple and their empirical treatment varies with the currently growing problem of antimicrobial resistance. Dermatologists are trained and prepared to treat these diseases, but their correct management requires active knowledge of national and international guidelines. The present document updates, reviews and summarizes the main expert recommendations on the management and treatment of these STIs.

AEDV Expert Recommendations on the Management of Suppurative Sexually Transmitted Infections

The incidence of sexually transmitted infections (STIs) is increasing in Spain. Suppurative STIs are one of the most frequent reasons for consultation in specialized centers. The reason for suppurative STIs is multiple and their empirical treatment varies with the currently growing problem of antimicrobial resistance. Dermatologists are trained and prepared to treat these diseases, but their correct management requires active knowledge of national and international guidelines. The present document updates, reviews and summarizes the main expert recommendations on the management and treatment of these STIs.

The gonorrhoea care cascade in general practice: a descriptive study to explore gonorrhoea management utilising electronic medical records

Background Gonorrhoea notification rates in Australia have more than doubled between 2014 and 2019. We explored gonorrhoea testing patterns and management of gonorrhoea infection in general practice. Methods We analysed de-identified electronic medical record data for individuals who attended 73 Australian general practices (72 in the state of Victoria) between January 2018 and December 2020. The 'care cascade' model was utilised to explore gonorrhoea detection and management. Descriptive analysis and logistic regression were used to investigate factors associated with gonorrhoea testing, treatment and retesting. Results During the study period, there were a total of 1,027,337 clinical episodes. Of these, 5.6% (n =57,847, 95% confidence interval [CI] 4.5-6.7) involved a gonorrhoea test and 1.1% (n =637, 95% CI 0.8-1.4) tested positive. Of the 637 gonorrhoea cases, 48.4% (n =308, 95% CI 29.8-67.0) had an Australian guideline-recommended dual antibiotic prescription (ceftriaxone and azithromycin) recorded. Of 329 cases without a dual antibiotic prescription, 84.2% (n =277, 95% CI 77.5-90.9) had reattended the clinic. Among the 206 gonorrhoea cases with dual antibiotic prescription recorded in 2018 and 2019, 32.0% (n =66, 95% CI 25.3-38.8) were retested from 6weeks to 6months post-treatment. Of the 140 gonorrhoea cases that were not retested, 54.3% (n =76, 95% CI 46.8-61.8) reattended the clinic within 6months of treatment. Conclusion The low proportion of gonorrhoea cases prescribed recommended antibiotics and retested within recommended timeframes suggests opportunities for integrating Australian STI guidelines into primary care. Further exploration of care pathways is warranted to determine if care was provided but not recorded, provided elsewhere or not provided.

Trends in fluoroquinolone prescribing in UK primary and secondary care between 2019 and 2023

INTRODUCTION

Fluoroquinolones are important antibiotics but have associations with a number of adverse outcomes. A recent (January 2024) decision by the UK drug regulator, the Medicines and Health Regulatory Authority (MHRA), restricted systemic use of these antibiotics to when 'absolutely necessary'. One stated reason for the ban was the failure of previous guidance (2019, 2023) to reduce prescribing, with the MHRA stating there had been 'no change in prescribing' of fluoroquinolones in relation to guidance.

METHODS

We evaluated the trend in prescribing of fluoroquinolones and comparator antibiotics using national data for all primary care practices in England from 2019 to 2023. We calculated the percent change in prescribing of fluoroquinolones using linear regression, comparing with other antibacterials. We also performed analysis on secondary care prescribing and included hospital inpatient stay data.

RESULTS

In primary care, there was a negative trend in fluoroquinolone item dispensing, with a 4.2% reduction in items dispensed per year (95% CI -5.2% to -3.3%; P = 6 × 10-13). This occurred despite no change in overall antibacterial prescription and no decrease in comparator antibiotics. Secondary care data showed stable prescription of fluoroquinolones, but comparator antibiotics increased, leading to relatively fewer prescriptions compared with other agents.

CONCLUSIONS

There was a reduction in fluoroquinolone prescribing in England in absolute and relative terms between 2019 and 2023 in primary care, and absolute terms in secondary care. These findings do not support the MHRA's claim that there has been no change in prescribing in response to warnings.

Ceftriaxone-resistant Neisseria gonorrhoeae detected in England, 2015-24: an observational analysis

OBJECTIVES

Since June 2022, there has been a rise in the number of ceftriaxone-resistant Neisseria gonorrhoeae cases detected in England (n = 15), of which a third were XDR. We describe the demographic and clinical details of the recent cases and investigate the phenotypic and molecular characteristics of the isolates. For a comprehensive overview, we also reviewed 16 ceftriaxone-resistant cases previously identified in England since December 2015 and performed a global genomic comparison of all publicly available ceftriaxone-resistant N. gonorrhoeae strains with mosaic penA alleles.

METHODS

All N. gonorrhoeae isolates resistant to ceftriaxone (MIC > 0.125 mg/L) were whole-genome sequenced and compared with 142 global sequences of ceftriaxone-resistant N. gonorrhoeae. Demographic, behavioural and clinical data were collected.

RESULTS

All cases were heterosexual, and most infections were associated with travel from the Asia-Pacific region. However, some had not travelled outside England within the previous few months. There were no ceftriaxone genital treatment failures, but three of five pharyngeal infections and the only rectal infection failed treatment. The isolates represented 13 different MLST STs, and most had the mosaic penA-60.001 allele. The global genomes clustered into eight major phylogroups, with regional associations. All XDR isolates belonged to the same phylogroup, represented by MLST ST16406.

CONCLUSIONS

Most cases of ceftriaxone-resistant N. gonorrhoeae detected in England were associated with travel from the Asia-Pacific region. All genital infections were successfully treated with ceftriaxone, but there were extragenital treatment failures. Ceftriaxone resistance continues to be associated with the penA-60.001 allele within multiple genetic backgrounds and with widespread dissemination in the Asia-Pacific region.

Differential contribution of PBP occupancy and efflux on the effectiveness of β-lactams at their target site in clinical isolates of Neisseria gonorrhoeae

Neisseria gonorrhoeae exhibits alarming antibiotic resistance trends and poses a significant challenge in therapeutic management. This study aimed to explore the association of penA alleles with penicillin-binding protein (PBP) occupancy patterns and reduced outer membrane permeability, impacting susceptibility to last-line cephalosporins and potential β-lactam candidates. The whole genome sequence, the MICs and PBP IC50s were determined for 12 β-lactams and β-lactamase inhibitors in 8 clinical isolates with varying β-lactam sensitivity, 2 ATCC, and 3 WHO cephalosporin-resistant reference strains. The genetic analysis identified diverse determinants of β-lactam resistance including penA, ponA, porB, and mtrR alterations. Mosaic penA alleles were confirmed to be key determinants of cephalosporin resistance, with notable impacts on PBP2 IC50 affinities (in the presence of all PBPs). Substitutions in positions V316 and A501 exhibited significant effects on β-lactam PBP2 occupancy and MICs. PBP1 inhibition showed marginal effect on β-lactam sensitivity and PBP3 acted as a sink target. Ertapenem and piperacillin emerged as potential therapies against cephalosporin-resistant N. gonorrhoeae strains, along with combination therapies involving tazobactam and/or efflux inhibitors. The study determined the β-lactam PBP-binding affinities of last-line cephalosporins and alternative β-lactam candidates in strains carrying different penA alleles for the first time. These findings provide insights for developing new antimicrobial agents and enhancers against emerging resistant strains. Further research is warranted to optimize therapeutic interventions for cephalosporin-resistant N. gonorrhoeae infections.

Separating Infectious Proctitis from Inflammatory Bowel Disease-A Common Clinical Conundrum

Proctitis refers to inflammation in the rectum and may result in rectal bleeding, discharge, urgency, tenesmus, and lower abdominal pain. It is a common presentation, particularly in genitourinary medicine and gastroenterology, as the two most common causes are sexually transmitted infections and inflammatory bowel disease. The incidence of infective proctitis is rising, particularly amongst high-risk groups, including men who have sex with men, those with HIV seropositive status, and those participating in high-risk sexual behaviours. The most commonly isolated organisms are Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema palladium, herpes simplex virus, and Mycoplasma genitalium. Recently, proctitis was also identified as a common feature during the Mpox outbreak. Distinguishing infective proctitis from inflammatory bowel disease remains a significant clinical challenge as there is significant overlap in the clinical presentation and their endoscopic and histological features. This review compares and highlights the distinguishing hallmarks of both inflammatory and infective causes of proctitis. It provides a practical guide to describe the key features that clinicians should focus on in both clinical and key diagnostic investigations to avoid potential misdiagnosis.

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.

Prevalence of Cefixime-Resistant Neisseria gonorrhoeae in Melbourne, Australia, 2021-2022

While ceftriaxone remains the first-line treatment for gonorrhea, the US Centers for Disease Control and Prevention recommended cefixime as a second-line treatment in 2021. We tested 1176 Neisseria gonorrhoeae isolates among clients attending the Melbourne Sexual Health Centre in 2021 and 2022. The prevalence of cefixime resistance was 6.3% (74/1176), azithromycin resistance was 4.9% (58/1176), and ceftriaxone resistance was 0% (0/1176). Cefixime resistance was highest among women (16.4%, 10/61), followed by men who have sex with women (6.4%, 7/109) and men who have sex with men (5.8%, 57/982). The prevalence of cefixime-resistant N gonorrhoeae exceeds the threshold of the 5% resistance level recommended by the World Health Organization; thus, cefixime treatment would have limited benefits in Australia.

Characterisation of Neisseria gonorrhoeae strain differences in patients with multisite infection

BACKGROUND

Neisseria gonorrhoeae, the aetiological agent of gonorrhoea, is an increasing global health priority due to high levels of antimicrobial resistance (AMR). It is estimated that up to 42% of patients are infected at multiple anatomical sites simultaneously. Previous studies identified that 7%-40% of those with multisite infection have different strains infecting different sites, with potentially different antimicrobial susceptibility profiles. This study aims to estimate the proportion of patients with multisite infection through differential antimicrobial susceptibility testing (AST) profiles and sequence-based molecular methods.

METHODS

This was a cross-sectional study of multisite gonococcal isolates provided by three National Health Service laboratories. Minimum inhibitory concentrations (MICs) for cefixime, ceftriaxone, azithromycin, ciprofloxacin, tetracycline and spectinomycin were determined. Possible multistrain infections were defined as isolates with a significant difference in MIC to at least one antimicrobial. Whole genome sequencing (WGS) was performed to determine multistrain infection through N. gonorrhoeae multiantigen sequence typing (NG-MAST), N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR), multilocus sequencing typing (MLST) and single nucleotide polymorphism (SNP) phylogeny, and to compare AST profiles with identified AMR genes.

RESULTS

Ninety-one isolates were collected from 41 patients with multisite infections. Of these 41 patients, 6 (14.6%) had N. gonorrhoeae isolates with discordant MICs. WGS-based typing confirmed that four out of six patients were infected with different gonococcal strains. The relatedness of isolates with the same MLST across multiple patients was differentiated using SNP-based analysis, and this included the identification of a potential transmission event. WGS-based AMR prediction for all antimicrobials tested correlated well with the phenotypic data.

CONCLUSION

This study demonstrates that potentially a significant proportion of patients with multisite infections are infected with multiple gonococcal strains, with differing AST profiles, at different anatomical sites. This has implications for patient sampling, susceptibility testing protocols, AMR surveillance and potentially appropriate antibiotic therapy.

Use of a meningococcal group B vaccine (4CMenB) in populations at high risk of gonorrhoea in the UK

The meningococcal group B vaccine, 4CMenB, is a broad-spectrum, recombinant protein vaccine that is licensed for protection against meningococcal group B disease in children and adults. Over the past decade, several observational studies supported by laboratory studies have reported protection by 4CMenB against gonorrhoea, a sexually transmitted infection caused by Neisseria gonorrhoeae. Gonorrhoea is a major global public health problem, with rising numbers of diagnoses and increasing resistance to multiple antibiotics. In England, more than 82 000 cases of gonorrhoea were diagnosed in 2022, with nearly half of the cases diagnosed among gay, bisexual, and other men who have sex with men. There are currently no licensed vaccines against gonorrhoea but 4CMenB is estimated to provide 33-47% protection against gonorrhoea. On Nov 10, 2023, the UK Joint Scientific Committee on Vaccination and Immunisation agreed that a targeted programme should be initiated using 4CMenB to prevent gonorrhoea among individuals at higher risk of infection attending sexual health services in the UK. This decision was made after reviewing evidence from retrospective and prospective observational studies, laboratory and clinical data, national surveillance reports, and health economic analyses. In this Review, we summarise the epidemiology of invasive meningococcal disease and gonorrhoea in England, the evidence supporting the use of 4CMenB for protection against gonorrhoea, and the data needed to inform long-term programme planning and extension to the wider population.

Epidemiological impact of Neisseria gonorrhoeae and Chlamydia trachomatis screening in men having sex with men: a modelling study

OBJECTIVES

The impact of the systematic screening of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) in men having sex with men (MSM) on these pathogens' epidemiology remains unclear. We conducted a modelling study to analyse this impact in French MSM.

METHODS

We modelled NG and CT transmission using a site-specific deterministic compartmental model. We calibrated NG and CT prevalence at baseline using results from MSM enrolled in the Dat'AIDS cohort. The baseline scenario was based on 1 million MSM, 40 000 of whom were tested every 90 days and 960 000 every 200 days. Incidence rate ratios (IRRs) at steady state were simulated for NG, CT, NG and/or CT infections, for different combinations of tested sites, testing frequency and numbers of frequently tested patients.

RESULTS

The observed prevalence rate was 11.0%, 10.5% and 19.1% for NG, CT and NG and/or CT infections. The baseline incidence rate was estimated at 138.2 per year per 100 individuals (/100PY), 86.8/100PY and 225.0/100PY for NG, CT and NG and/or CT infections. Systematically testing anal, pharyngeal and urethral sites at the same time reduced incidence by 14%, 23% and 18% (IRR: 0.86, 0.77 and 0.82) for NG, CT and NG and/or CT infections. Reducing the screening interval to 60 days in frequently tested patients reduced incidence by 20%, 29% and 24% (IRR: 0.80, 0.71 and 0.76) for NG, CT and NG and/or CT infections. Increasing the number of frequently tested patients to 200 000 reduced incidence by 29%, 40% and 33% (IRR: 0.71, 0.60 and 0.67) for NG, CT and NG and/or CT infections. No realistic scenario could decrease pathogens' incidence by more than 50%.

CONCLUSIONS

To curb the epidemic of NG and CT in MSM, it would not only be necessary to drastically increase screening, but also to add other combined interventions.

The re-emergence of sexually transmissible multidrug resistant Shigella flexneri 3a, England, United Kingdom

Shigellosis is an enteric infection that transmits through the faecal-oral route, which can occur during sex between men who have sex with men (MSM). Between 2009 and 2014, an epidemic of sexually transmissible Shigella flexneri 3a occurred in England that subsequently declined. However, from 2019 to 2021, despite SARS-CoV-2 restrictions, S. flexneri 3a continued to re-emerge. We explored possible drivers of re-emergence by comparing host demography and pathogen genomics. Cases were primarily among 35-64 year old men in London. Genomic analyses of 502 bacterial isolates showed that the majority (58%) of re-emerging MSM strains were a clonal replacement of the original, with reduced antimicrobial resistance, conservation of plasmid col156_1, and two SNPs with 19 predicted effects. The absence of major changes in the pathogen or host demographics suggest that other factors may have driven the re-emergence of S. flexneri 3a and highlight the need for further work in the area.

The novel 2024 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations and superseded WHO N. gonorrhoeae reference strains-phenotypic, genetic and reference genome characterization

OBJECTIVES

MDR and XDR Neisseria gonorrhoeae strains remain major public health concerns internationally, and quality-assured global gonococcal antimicrobial resistance (AMR) surveillance is imperative. The WHO global Gonococcal Antimicrobial Surveillance Programme (GASP) and WHO Enhanced GASP (EGASP), including metadata and WGS, are expanding internationally. We present the phenotypic, genetic and reference genome characteristics of the 2024 WHO gonococcal reference strains (n = 15) for quality assurance worldwide. All superseded WHO gonococcal reference strains (n = 14) were identically characterized.

MATERIAL AND METHODS

The 2024 WHO reference strains include 11 of the 2016 WHO reference strains, which were further characterized, and four novel strains. The superseded WHO reference strains include 11 WHO reference strains previously unpublished. All strains were characterized phenotypically and genomically (single-molecule PacBio or Oxford Nanopore and Illumina sequencing).

RESULTS

The 2024 WHO reference strains represent all available susceptible and resistant phenotypes and genotypes for antimicrobials currently and previously used (n = 22), or considered for future use (n = 3) in gonorrhoea treatment. The novel WHO strains include internationally spreading ceftriaxone resistance, ceftriaxone resistance due to new penA mutations, ceftriaxone plus high-level azithromycin resistance and azithromycin resistance due to mosaic MtrRCDE efflux pump. AMR, serogroup, prolyliminopeptidase, genetic AMR determinants, plasmid types, molecular epidemiological types and reference genome characteristics are presented for all strains.

CONCLUSIONS

The 2024 WHO gonococcal reference strains are recommended for internal and external quality assurance in laboratory examinations, especially in the WHO GASP, EGASP and other GASPs, but also in phenotypic and molecular diagnostics, AMR prediction, pharmacodynamics, epidemiology, research and as complete reference genomes in WGS analysis.

Managing treatment failure in Neisseria gonorrhoeae infection: current guidelines and future directions

Due to the continued emergence of resistance to extended-spectrum cephalosporin antibiotics, clinicians are increasingly more likely to encounter cases of Neisseria gonorrhoeae treatment failure. The current international treatment guidelines offer few regimens for cases of N gonorrhoeae infection that do not respond to first-line therapy, and there are many complexities that should be considered with such regimens; these include regional variations in resistance to alternative agents, access to different antibiotics, and penetration of those antibiotics within different tissues. Further, such regimens do not account for the challenges of treating pharyngeal infections; many patients who have not responded to treatment with extended-spectrum cephalosporin antibiotics to date have had pharyngeal involvement. In addition, pharyngeal infections play a pivotal role in the emergence and spread of antimicrobial resistance in N gonorrhoeae and are more difficult to treat than urogenital infections because of the unfavourable pharmacokinetics of cephalosporins in pharyngeal tissues. Here, we summarise the current guidelines, provide additional approaches and considerations for clinicians, and highlight knowledge gaps that should be addressed to ensure appropriate therapy in cases of treatment failure.

Vaccine value profile for Neisseria gonorrhoeae

Neisseria gonorrhoeae infection (gonorrhoea) is a global public health challenge, causing substantial sexual and reproductive health consequences, such as infertility, pregnancy complications and increased acquisition or transmission of HIV. There is an urgency to controlling gonorrhoea because of increasing antimicrobial resistance to ceftriaxone, the last remaining treatment option, and the potential for gonorrhoea to become untreatable. No licensed gonococcal vaccine is available. Mounting observational evidence suggests that N. meningitidis serogroup B outer membrane vesicle-based vaccines may induce cross-protection against N. gonorrhoeae (estimated 30%-40% effectiveness using the 4CMenB vaccine). Clinical trials to determine the efficacy of the 4CMenB vaccine against N. gonorrhoeae are underway, as are Phase 1/2 studies of a new gonococcal-specific vaccine candidate. Ultimately, a gonococcal vaccine must be accessible, affordable and equitably dispensed, given that those most affected by gonorrhoea are also those who may be most disadvantaged in our societies, and most cases are in less-resourced settings. This vaccine value profile (VVP) provides a high level, holistic assessment of the current data to inform the potential public health, economic and societal value of pipeline vaccines. This was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations. All contributors have extensive expertise on various elements of the N. gonorrhoeae VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using published data obtained from peer-reviewed journals or reports.

Antimicrobial treatment and resistance in sexually transmitted bacterial infections

Sexually transmitted infections (STIs) have been part of human life since ancient times, and their symptoms affect quality of life, and sequelae are common. Socioeconomic and behavioural trends affect the prevalence of STIs, but the discovery of antimicrobials gave hope for treatment, control of the spread of infection and lower rates of sequelae. This has to some extent been achieved, but increasing antimicrobial resistance and increasing transmission in high-risk sexual networks threaten this progress. For Neisseria gonorrhoeae, the only remaining first-line treatment (with ceftriaxone) is at risk of becoming ineffective, and for Mycoplasma genitalium, for which fewer alternative antimicrobial classes are available, incurable infections have already been reported. For Chlamydia trachomatis, in vitro resistance to first-line tetracyclines and macrolides has never been confirmed despite decades of treatment of this highly prevalent STI. Similarly, Treponema pallidum, the cause of syphilis, has remained susceptible to first-line penicillin.

Antimicrobial Resistance in Gonorrhea

Antimicrobial resistance is a global public health emergency. The World Health Organization recently highlighted the growing number of new sexually transmitted infections such as gonorrhea, syphilis, and Chlamydia, which are resistant to common antibiotics. The phenomenon is also on the rise due to increasing intercontinental travel. Emerging antibiotic-resistant strains of gonorrhea are particularly associated with international spread from Southeast Asian travelers. Infection with Neisseria gonorrhoeae can cause a wide spectrum of associated diseases such as dermatitis, arthritis and septic arthritis, and pelvic inflammatory disease, and can even lead to serious health consequences for the individual. Natural infection confers no immunity, and vaccination is not available currently, although in several countries, it has been reported that the antimeningococcal vaccine may protect against gonorrhea. Implementing all necessary preventive measures is crucial, as well as appropriate and timely diagnostic methods and effective antimicrobial therapeutic treatments in the correct modalities to avoid the increase of forms of gonorrhea that are resistant to common antibiotics and difficult to eradicate.

Impact of molecular ciprofloxacin resistance testing in management of gonorrhoea in a large urban clinic

OBJECTIVES

Antibiotic resistance in gonorrhoea is of significant public health concern with the emergence of resistance to last-line therapies such as ceftriaxone. Despite around half of Neisseria gonorrhoeae isolates tested in the UK being susceptible to ciprofloxacin, very little ciprofloxacin is used in clinical practice. Testing for the S91F mutation associated with ciprofloxacin resistance is now available in CE-marked assays and may reduce the requirement for ceftriaxone, but many patients are treated empirically, or as sexual contacts, which may limit any benefit. We describe the real-world impact of such testing on antimicrobial use and clinical outcomes in people found to have gonorrhoea in a large urban UK sexual health clinic.

METHODS

Molecular ciprofloxacin resistance testing (ResistancePlus GC assay (SpeeDx)) was undertaken as an additional test after initial diagnosis (m2000 Realtime CT/NG assay (Abbott Molecular)) in those not already known to have had antimicrobial treatment. Data from a 6-month period (from March to September 2022) were analysed to determine treatment choice and treatment outcome.

RESULTS

A total of 998 clinical samples tested positive for N. gonorrhoeae in 682 episodes of infection. Of the 560 (56%) samples eligible for resistance testing, 269 (48.0%) were reported as wild-type, 180 (32.1%) were predicted to be resistant, 63 (11.3%) had an indeterminate resistance profile, and in 48 (8.6%) samples, N. gonorrhoeae was not detected. Ciprofloxacin was prescribed in 172 (75%) of 228 episodes in which the wild-type strain was detected. Four (2%) of those treated with ciprofloxacin had a positive test-of-cure sample by NAAT, with no reinfection risk. All four had ciprofloxacin-susceptible infection by phenotypic antimicrobial susceptibility testing.

CONCLUSIONS

In routine practice in a large UK clinic, molecular ciprofloxacin resistance testing led to a significant shift in antibiotic use, reducing use of ceftriaxone. Testing can be targeted to reduce unnecessary additional testing. Longer term impact on antimicrobial resistance requires ongoing surveillance.

Investigating the cause of increased tetracycline-resistant Neisseria gonorrhoeae in England, 2016-20

BACKGROUND

Antimicrobial resistance in Neisseria gonorrhoeae is a global public health concern. Tetracycline resistance (TetR) increased from 39.4% to 75.2% between 2016 and 2021 in N. gonorrhoeae isolates collected through national surveillance in England, despite the absence of use of tetracyclines for the treatment of gonorrhoea.

OBJECTIVES

We investigated whether there was correlation between bacterial sexually transmitted infection (STI) tests performed and treatment with antimicrobials, with increased TetR in N. gonorrhoeae.

METHODS

We examined correlations between bacterial STI tests, antimicrobial treatment and TetR in N. gonorrhoeae, using national surveillance data from three large sexual health services (SHS) in London during 2016-20. Doxycycline prescribing data and antibiograms of a non-STI pathogen from distinct patient groups (sexual health, obstetric and paediatric), at a large London hospital, were analysed to identify if doxycycline use in SHS was associated with resistance in a non-STI organism.

RESULTS

A substantial increase in TetR was observed, particularly in isolates from gay, bisexual and other MSM (GBMSM). Strong positive correlations were observed exclusively in GBMSM between N. gonorrhoeae TetR and both bacterial STI tests (r = 0.97, P = 0.01) and antimicrobial treatment (r = 0.87, P = 0.05). Doxycycline prescribing increased dramatically during the study period in SHS. Prevalence of TetR in Staphylococcus aureus was higher in isolates sourced from SHS attendees than those from other settings.

CONCLUSIONS

Frequent screening of GBMSM at higher risk of STIs, such as those on pre-exposure prophylaxis (PrEP) leading to/and increased use of doxycycline for the treatment of diagnosed infections, may account for the increase in TetR in N. gonorrhoeae.

Recent dynamics in Neisseria gonorrhoeae genomic epidemiology in Brazil: antimicrobial resistance and genomic lineages in 2017-20 compared to 2015-16

OBJECTIVES

Regular quality-assured WGS with antimicrobial resistance (AMR) and epidemiological data of patients is imperative to elucidate the shifting gonorrhoea epidemiology, nationally and internationally. We describe the dynamics of the gonococcal population in 11 cities in Brazil between 2017 and 2020 and elucidate emerging and disappearing gonococcal lineages associated with AMR, compare to Brazilian WGS and AMR data from 2015 to 2016, and explain recent changes in gonococcal AMR and gonorrhoea epidemiology.

METHODS

WGS was performed using Illumina NextSeq 550 and genomes of 623 gonococcal isolates were used for downstream analysis. Molecular typing and AMR determinants were obtained and links between genomic lineages and AMR (determined by agar dilution/Etest) examined.

RESULTS

Azithromycin resistance (15.6%, 97/623) had substantially increased and was mainly explained by clonal expansions of strains with 23S rRNA C2611T (mostly NG-STAR CC124) and mtr mosaics (mostly NG-STAR CC63, MLST ST9363). Resistance to ceftriaxone and cefixime remained at the same levels as in 2015-16, i.e. at 0% and 0.2% (1/623), respectively. Regarding novel gonorrhoea treatments, no known zoliflodacin-resistance gyrB mutations or gepotidacin-resistance gyrA mutations were found. Genomic lineages and sublineages showed a phylogenomic shift from sublineage A5 to sublineages A1-A4, while isolates within lineage B remained diverse in Brazil.

CONCLUSIONS

Azithromycin resistance, mainly caused by 23S rRNA C2611T and mtrD mosaics/semi-mosaics, had substantially increased in Brazil. This mostly low-level azithromycin resistance may threaten the recommended ceftriaxone-azithromycin therapy, but the lack of ceftriaxone resistance is encouraging. Enhanced gonococcal AMR surveillance, including WGS, is imperative in Brazil and other Latin American and Caribbean countries.

Comparison of gradient diffusion and molecular methods using Allplex™ NG&DR assay (Seegene®) for macrolide and fluoroquinolone screening resistance in Neisseria gonorrhoeae

Antimicrobial resistance in Neisseria gonorrhoeae (NG) is increasing worldwide. Second-line treatments with macrolides or fluoroquinolones are an option for NG infections in some cases following the STI guideline recommendations. In our study, we compared the gradient diffusion test using EUCAST 2024 breakpoints with a new molecular method using the Allplex™ NG&DR assay (Seegene®) including A2059G/C2611 mutations (23S rRNA) associated with high/moderate-level macrolide resistance and S91F mutation (gyrA) relationship with fluoroquinolone resistance in NG isolates (n = 100). We calculated the sensitivity, specificity, and correlation of the molecular test for fluoroquinolone using the gradient diffusion as the reference method. In twenty-three strains was not detected any mutation associated with macrolides or fluoroquinolone resistance. No A2059G/C2611T mutations were detected, and the S91F mutations were detected in 77 out of the 100 isolates screened. Twenty-three NG isolates were reported to be resistant to azithromycin (ECOFF: >1 mg/L), and 78 NG isolates were resistant to ciprofloxacin (MIC: >0.06 mg/L). The molecular method showed a sensitivity of 96.1% and, a specificity of 90.9% for fluoroquinolone susceptibility, but the statistical analysis between the molecular test and gradient diffusion test was not statistically significant for fluoroquinolone resistance (p = 1). Statistical analysis was not performed for macrolides because of the absence of positive RT-PCR results. According to our data, Allplex™ assay cannot replace the gradient diffusion test for macrolide resistance. However, the assay could be used to test fluoroquinolone resistance in NG isolates as a replacement for phenotypic methods.

Addressing Sexually Transmitted Infections Due to Neisseria gonorrhoeae in the Present and Future

It was in the 1800s when the first public publications about the infection and treatment of gonorrhoea were released. However, the first prevention programmes were only published a hundred years later. In the 1940s, the concept of vaccination was introduced into clinical prevention programmes to address early sulphonamide resistance. Since then, tons of publications on Neisseria gonorrhoeae are undisputed, around 30,000 publications today. Currently, the situation seems to be just as it was in the last century, nothing has changed or improved. So, what are we doing wrong? And more importantly, what might we do? The review presented here aims to review the current situation regarding the resistance mechanisms, prevention programmes, treatments, and vaccines, with the challenge of better understanding this special pathogen. The authors have reviewed the last five years of advancements, knowledge, and perspectives for addressing the Neisseria gonorrhoeae issue, focusing on new therapeutic alternatives.

Current alternative therapies for treating drug-resistant Neisseria gonorrhoeae causing ophthalmia neonatorum

Ophthalmia neonatorum is a microbial contraction, damaging eyesight, occurring largely among neonates. Infants are particularly vulnerable to bacterial infections acquired during birth from infected mothers, especially from Neisseria gonorrhoeae and Chlamydia trachomatis. Over the decades, N. gonorrhoeae is alarmingly developing a resistance to most antibiotics currently prescribed. To counter this challenge, it is imperative to find potent and cost-effective therapeutic agents for prophylaxis and treatment, to which the N. gonorrhoeae cannot easily develop resistance. This review showcases alternate therapies such as antimicrobial-fatty acids, -peptides, -nano-formulations etc., currently evident against N. gonorrhoeae-mediated ophthalmia neonatorum, which remains a major cause of ocular morbidity, blindness and even death among neonates in developing countries.

Clinic-based evaluation of the dual Xpert CT/NG assay on the GeneXpert System for screening for extragenital chlamydial and gonococcal infections amongst men who have sex with men

BACKGROUND

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections have increased globally. Asymptomatic infections represent a significant risk of long-term complications. Men who have sex with men (MSM) are disproportionally affected, underscoring the need to offer screening programmes to this population. CT/NG Point of Care Testing (POCT) constitutes a strategic tool to improve the continuum of STI care, however extensive real-life evaluations amongst at risk populations are lacking. The aim of this study is to estimate the GeneXpert CT/NG assay performance and usability for CT and NG at genital and extragenital sites for screening amongst MSM.

METHODS

This study was a multi-site sexual health clinic-based evaluation (Italy, Malta and Peru) with consecutive enrolment. A first void urine sample (divided in two aliquots), two oropharyngeal and two anorectal swabs were collected for each study participant. One specimen set (one for each anatomical site) was tested with the dual index test (Cepheid) at the clinics by the healthcare staff, the other set with FDA/CE approved Nucleic Acid Amplification Tests (NAATs) at the laboratory. Clinical sites and reference laboratories participated in an internal and external quality control programme. Sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values for each anatomical site were estimated using a meta-analytic approach.

RESULTS

One thousand seven hundred two MSM were recruited across all clinical sites for a total of 5049 biological specimens. NG and CT were respectively detected in 274 and 287 of samples. Overall, the NG POCT sensitivity and specificity was 91.43% and 99.75% in urine (LR + 372.80, LR- 0.09), 89.68% and 99.55% in rectal specimens (LR + 197.30, LR- 0.10) and 75.87% and 98.77% at the pharynx respectively (LR + 61.94, LR- 0.24). The CT component of the POCT sensitivity was 84.82% and specificity 99.63% in urine (LR + 228.68, LR- 0.15), 78.07% and 99.19% respectively on rectal site (LR + 96.23, LR-0.22), 67.79% and 99.88% respectively at pharyngeal site (LR + 554.89, LR- 0.32). 95.95% of MSM reported to be willing to wait for POCT results and no provider reported difficulties in terms of performance or interpretation of the results of the Xpert CT/NG.

CONCLUSION

Rapid turnaround time, ease of use and high acceptability make the Xpert CT/NG testing system a strategic tool for increasing testing frequency, reaching those not yet tested and offering the possibility of immediate treatment if needed. The assay showed good negative likelihood ratios and confirms its use to rule out CT/NG infections. Sensitivity varied across sites and pathogens. Periodic staff training at the testing sites should be mandatory.

Emergence of high-level azithromycin-resistant Neisseria gonorrhoeae causing male urethritis in Johannesburg, South Africa, 2021

BACKGROUND

In South Africa, Neisseria gonorrhoeae , which is the predominant cause of male urethritis, is treated syndromically using dual ceftriaxone and azithromycin therapy. We determined antimicrobial susceptibilities of N. gonorrhoeae isolates from urethral discharge specimens, and genetically characterised those with elevated minimum inhibitory concentrations (MICs) for first-line antimicrobials.

METHODS

Routine antimicrobial susceptibility testing (AST) of N. gonorrhoeae isolates included E-test for ceftriaxone, cefixime and gentamicin and agar dilution for azithromycin and spectinomycin. Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) was performed for isolates with elevated MICs to identify antimicrobial resistance (AMR) determinants, and Neisseria gonorrhoeae Multi-Antigen Sequence Typing (NG-MAST) was used to determine strain relatedness.

RESULTS

N. gonorrhoeae was cultured from urethral discharge swab specimens obtained from 196 of 238 (82.4%) men presenting to a primary healthcare facility in Johannesburg in 2021. All viable isolates were susceptible to extended-spectrum cephalosporins. Four isolates had high azithromycin MICs ranging from 32mg/L to >256mg/L and grouped into two novel NG-MAST and NG-STAR groups. Two isolates from Group 1 (NG-MAST ST20366, NG-STAR ST4322) contained mutated mtrR (G45D) and 23S rRNA (A2059G) alleles, while the two isolates from Group 2 (NG-MAST ST20367, NG-STAR ST4323) had different mutations in mtrR (A39T) and 23S rRNA (C2611T).

CONCLUSIONS

We report the first cases of high-level azithromycin resistance in N. gonorrhoeae from South Africa. Continued AMR surveillance is critical to detect increasing azithromycin resistance prevalence in N. gonorrhoeae , which may justify future modifications to the STI syndromic management guidelines.

Antibiotic susceptibility and genotypic characterization of Neisseria gonorrhoeae isolates in the Comunidad Valenciana (Spain): GONOvig project

INTRODUCTION

The increase in sexually transmitted infections (STI) caused by Neisseria gonorrhoeae (NG) worldwide, together with the decrease in antibiotic susceptibility, forced us to understand the epidemiology of gonococcal infection.

METHODS

The GONOvig project analyzed, comparatively following CLSI and EUCAST criteria, the antibiotic susceptibility of 227 NG strains collected in thirteen representative hospitals of the Valencia Community (CV) between 2013 and 2018. Additionally, molecular typing of 175 strains using the NG multi-antigen sequence typing technique (NG-MAST) was performed.

RESULTS

High rates of resistance to tetracycline (38.2% by CLSI and 50.9% by EUCAST) and ciprofloxacin (49.1% CLSI and 54% EUCAST), and low percentages of resistance to spectinomycin (0%), cefixime (0.5% CLSI but 5.9% EUCAST), and ceftriaxone (1.5% CLSI and 2.4% EUCAST) were detected. Azithromycin resistance was 6% (both CLSI and EUCAST). Molecular analysis revealed the presence of 86 different sequence types (ST), highlighting ST2992 (7.4%), ST3378 (6.9%), ST2400 (4.6%) and ST13288 (6.9%), which was associated with resistance to cefixime (P=.031). The main genogroups (G) were G1407 (13.1%), G2992 (10.3%), G2400 (6.3%) and G387 (3.4%). G1407 and G2400 were associated with resistance to ciprofloxacin (P<.03).

CONCLUSION

Low resistance to ceftriaxone, a worrying resistance to azithromycin and a wide variety of circulating sequence types have been detected, some of which show correlation with certain resistance profiles.

STI pathogens in the oropharynx: update on screening and treatment

PURPOSE OF REVIEW

The rise in antimicrobial resistance in several STI pathogens such as Neisseria gonorrhoeae has become a public health threat as only one first-line treatment remains. Reducing screening interval for gonorrhoea and chlamydia in high-prevalence populations has been proposed to address antimicrobial stewardship, but this remains controversial. This review aimed to revisit the epidemiology of infections at the oropharynx and review the current screening recommendations and treatment guidelines in different populations.

RECENT FINDINGS

Emerging evidence suggests that the oropharynx is the primary anatomical site for gonorrhoea transmission but maybe not for chlamydia transmission. Most international guidelines recommend 3-monthly oropharyngeal gonorrhoea and chlamydia screening for high-prevalence populations (e.g. men who have sex with men) but not low-prevalence populations (e.g. heterosexuals) given the clinical and public health benefits of screening in low-prevalence populations are still unclear. Doxycycline remains the first-line treatment for oropharyngeal chlamydia in most guidelines. However, some countries have moved from dual therapy (ceftriaxone and azithromycin) to monotherapy (ceftriaxone) for oropharyngeal gonorrhoea treatment to address antimicrobial stewardship.

SUMMARY

The transmission of gonorrhoea and chlamydia is still not fully understood. Further work will be required to evaluate the benefits and harms of reducing screening in high-prevalence populations.

Phenotypic and genotypic characterization of Neisseria gonorrhoeae isolates among individuals at high risk for sexually transmitted diseases in Zurich, Switzerland

BACKGROUND

While ceftriaxone resistance remains scarce in Switzerland, global Neisseria gonorrhoeae (NG) antimicrobial resistance poses an urgent threat. This study describes clinical characteristics in MSM (men who have sex with men) diagnosed with NG infection and analyses NG resistance by phenotypic and genotypic means.

METHODS

Data of MSM enrolled in three clinical cohorts with a positive polymerase chain reaction test (PCR) for NG were analysed between January 2019 and December 2021 and linked with antibiotic susceptibility testing. Bacterial isolates were subjected to whole genome sequencing (WGS).

RESULTS

Of 142 participants, 141 (99%) were MSM and 118 (84%) living with HIV. Participants were treated with ceftriaxone (N = 79), azithromycin (N = 2), or a combination of both (N = 61). No clinical or microbiological failures were observed. From 182 positive PCR samples taken, 23 were available for detailed analysis. Based on minimal inhibitory concentrations (MICs), all isolates were susceptible to ceftriaxone, gentamicin, cefixime, cefpodoxime, ertapenem, zoliflodacin, and spectinomycin. Resistance to azithromycin, tetracyclines and ciprofloxacin was observed in 10 (43%), 23 (100%) and 11 (48%) of the cases, respectively. Analysis of WGS data revealed combinations of resistance determinants that matched with the corresponding phenotypic resistance pattern of each isolate.

CONCLUSION

Among the MSM diagnosed with NG mainly acquired in Switzerland, ceftriaxone MICs were low for a subset of bacterial isolates studied and no treatment failures were observed. For azithromycin, high occurrences of in vitro resistance were found. Gentamicin, cefixime, cefpodoxime, ertapenem, spectinomycin, and zoliflodacin displayed excellent in vitro activity against the 23 isolates underscoring their potential as alternative agents to ceftriaxone.

Evaluating the efficacy of different antibiotics against Neisseria gonorrhoeae: a pharmacokinetic/pharmacodynamic analysis using Monte Carlo simulation

BACKGROUND

With the widespread use of antibiotics, antimicrobial resistance in Neisseria gonorrhoeae is worsening. The objective of this study was to evaluate the efficacy changes of seven antibiotics in the treatment of N. gonorrhoeae by using Monte Carlo simulation combined with pharmacokinetics/pharmacodynamics/ (PK/PD).

METHODS

The minimum inhibitory concentration (MIC) of antibiotics against clinical isolates from 2013 to 2020 in Nanjing, China, was determined by agar dilution method. The probability of target attainment (PTA) was estimated at each MIC value and the cumulative fraction of response (CFR) was calculated to evaluate the efficacy of these regimens.

RESULTS

All dosage regimens of seven antibiotics achieved PTAs ≥ 90% for MIC ≤ 0.06 µg/ml. But when the MIC was increased to 1 µg/ml, PTAs at each MIC value exceeded 90% only for ceftriaxone 1,000 mg and 2,000 mg, zoliflodacin 2,000 mg and 3,000 mg. Among them, the CFR values of each dosing regimen against N. gonorrhoeae only for ceftriaxone, cefixime and zoliflodacin were ≥ 90% in Nanjing from 2013 to 2020.

CONCLUSIONS

Cephalosporins are still the first-line drugs in the treatment of gonorrhea. However, the elevated MIC values of cephalosporins can lead to decline in clinical efficacy of the conventional dose regimens, and increasing the dose of ceftriaxone to 1,000 mg-2,000 mg may improve the efficacy. In addition, zoliflodacin is possible to be a potential therapeutic agent in the future.

Maximizing the Neisseria gonorrhoeae confirmatory rate and the genotypic detection of ciprofloxacin resistance for samples screened with cobas CT/NG

Supplementary nucleic acid amplification testing for Neisseria gonorrhoeae (NG) is widely used to circumvent specificity problems associated with extragenital sites. Here, we compared different supplementary approaches for confirming NG-positive samples from the cobas 4800 CT/NG (c4800) and cobas 6800 CT/NG (c6800) assays using the ResistancePlusGC (RP-GC) assay, which in addition to detecting NG, also predicts ciprofloxacin susceptibility via NG gyrA characterization. Two different nucleic acid extraction techniques were investigated for RP-GC detection; extracts from c4800 (c4800-RP-GC) and MagNA Pure 96 (MP96-RP-GC). NG-positive (n = 300) and -negative (n = 150) samples in cobas PCR media from routine c4800 testing were retrospectively retested with c4800, c6800, c4800-RP-GC, and MP96-RP-GC. Selected samples were also tested with Xpert CT/NG (Xpert) for discrepant analysis. The gyrA status was compared to ETEST ciprofloxacin susceptibility or non-susceptibility for recovered isolates (n = 63). Extragenital confirmatory rates were higher for MP96-RP-GC (131/140; 93.6%) compared to c4800-RP-GC (126/146; 86.3%), albeit not significantly (P = 0.6677). Of 9 samples testing positive by c6800 and negative by MP96-RP-GC, 7/9 (77.8%) were also negative by Xpert. By contrast, the number of samples returning a valid gyrA status was significantly (P = 0.0003) higher for MP96-RP-GC (270/293; 92.2%) compared to c4800-RP-GC (245/298; 82.2%). The overall MP96-RP-GC gyrA status correlated 98.4% (61/62) with the reported ciprofloxacin sensitive (35/36; 97.2%) or non-susceptible (26/26; 100%) phenotype. Improved RP-GC confirmatory rates and reported gyrA status were observed using MP96 nucleic acids compared to c4800 extracts. The data further highlight the ongoing need for NG supplemental testing for oropharyngeal samples.

Cyr SB, Rönn MM, Salomon JA, Grad YH. The Impact of Rapid Drug Susceptibility Tests on Gonorrhea Burden and the Life Span of Antibiotic Treatments: A Modeling Study Among Men Who Have Sex With Men in the United States

Rapid point-of-care tests that diagnose gonococcal infections and identify susceptibility to antibiotics enable individualized treatment. This could improve patient outcomes and slow the emergence and spread of antibiotic resistance. However, little is known about the long-term impact of such diagnostics on the burden of gonorrhea and the effective life span of antibiotics. We used a mathematical model of gonorrhea transmission among men who have sex with men in the United States to project the annual rate of reported gonorrhea cases and the effective life span of ceftriaxone, the recommended antibiotic for first-line treatment of gonorrhea, as well as 2 previously recommended antibiotics, ciprofloxacin and tetracycline, when a rapid drug susceptibility test that estimates susceptibility to ciprofloxacin and tetracycline is available. The use of a rapid drug susceptibility test with ≥50% sensitivity and ≥95% specificity, defined in terms of correct ascertainment of drug susceptibility and nonsusceptibility status, could increase the combined effective life span of ciprofloxacin, tetracycline, and ceftriaxone by at least 2 years over 25 years of simulation. If test specificity is imperfect, however, the increase in the effective life span of antibiotics is accompanied by an increase in the rate of reported gonorrhea cases even under perfect sensitivity.

The Role of Emergency and Primary Care in Combating the Rise of Gonorrhea: Another Purview Paradox?

INTRODUCTION

Drug-resistant Neisseria gonorrhoeae is an urgent threat to public health. Novel prevention and treatment strategies are emerging, including immunizations, pharmacologic post-exposure prophylaxis, rapid molecular resistance assays, and novel antibiotics. However, where and how such strategies are optimally implemented remains unclear.

METHODS

We conducted a retrospective interrupted time series analysis of gonorrhea cases reported to the Massachusetts Department of Public Health. We collected names of treating providers from 2011 (n = 100) and 2022 (n = 108), and cross-referenced provider names with publicly available records from the Massachusetts Boards of Registration in Medicine and Nursing to identify provider type, specialty, year of terminal degree or licensure, and clinic type.

RESULTS

Of 208 providers, 111 (53.4%) were advanced care practitioners. Providers treated cases predominantly in community health centers (n = 65, 31.3%) and emergency departments or urgent care centers (n = 60, 28.8%). Only 11 (12.4%) of 89 physicians were trained in either adult or pediatric infectious diseases.

CONCLUSION

Our results indicate that the majority of gonorrhea cases in the Massachusetts are treated in non-specialty settings. The time is now to plan for implementation of the emerging strategies to avoid underutilization and assure uptake of interventions in settings positioned to reach persons diagnosed with gonorrhea who will benefit most.

Machine learning to predict ceftriaxone resistance using single nucleotide polymorphisms within a global database of Neisseria gonorrhoeae genomes

IMPORTANCE

Antimicrobial resistance in Neisseria gonorrhoeae is an urgent global health issue. The objectives of the study were to use a global collection of 12,936 N. gonorrhoeae genomes from the PathogenWatch database to evaluate different machine learning models to predict ceftriaxone susceptibility/decreased susceptibility using 97 mutations known to be associated with ceftriaxone resistance. We found the random forest classifier model had the highest performance. The analysis also reported the relative contributions of different mutations within the ML model predictions, allowing for the identification of the mutations with the highest importance for ceftriaxone resistance. A machine learning model retrained with the top five mutations performed similarly to the model using all 97 mutations. These results could aid in the development of molecular tests to detect resistance to ceftriaxone in N. gonorrhoeae. Moreover, this approach could be applied to building and evaluating machine learning models for predicting antimicrobial resistance in other pathogens.

Bacitracin enhances ceftriaxone susceptibility of the high-level ceftriaxone-resistant gonococcal FC428 clone

IMPORTANCE

Ceftriaxone-based antimicrobial therapies for gonorrhea are threatened by waning ceftriaxone susceptibility levels and the global dissemination of the high-level ceftriaxone-resistant gonococcal FC428 clone. Combination therapy can be an effective strategy to restrain the development of ceftriaxone resistance, and for that purpose, it is important to find an alternative antimicrobial to replace azithromycin, which has recently been removed in some countries from the recommended ceftriaxone plus azithromycin dual-antimicrobial therapy. Ideally, the second antimicrobial should display synergistic activity with ceftriaxone. We hypothesized that bacitracin might display synergistic activity with ceftriaxone because of their distinct mechanisms targeting bacterial cell wall synthesis. In this study, we showed that bacitracin indeed displays synergistic activity with ceftriaxone against Neisseria gonorrhoeae. Importantly, strains associated with the FC428 clone appeared to be particularly susceptible to the bacitracin plus ceftriaxone combination, which might therefore be an interesting dual therapy for further in vivo testing.

Impact of time of culture specimen collection on the recovery of Neisseria gonorrhoeae after a positive nucleic acid amplification test

OBJECTIVES

Culture of Neisseria gonorrhoeae remains essential for antimicrobial resistance (AMR) surveillance. We evaluated the effect of time of specimen collection on culture yield following a positive nucleic acid amplification test (NAAT).

METHODS

We retrospectively assessed N. gonorrhoeae culture yield among asymptomatic individuals (largely men who have sex with men) who attended for sexual health screening and had a positive NAAT. Participants underwent either same-day testing and notification (Drassanes Exprés) or standard screening with deferred testing.

RESULTS

Among 10 423 screened individuals, 809 (7.7%) tested positive for N. gonorrhoeae. A total of 995 different anatomical sites of infection culture was performed in 583 of 995 (58.6%) of anatomical sites (Drassanes Exprés 278 of 347, 80.1%; standard screening 305 of 648, 47.1%; p<0.001). Recovery was highest when culture specimens were collected within 3-7 days of screening with only a slight drop in recovery when the interval extended to 7 days . Recovery from pharynx was 38 of 149 (25.5%) within 3 days, 19 of 81 (23.4%) after 4-7 days (p=0.7245), 11 of 102 (10.7%) after 8-14 days (p<0.0036) and 1 of 22 (4.5%) with longer delays (p=0.00287). Recovery from rectum was 49 of 75 (65.3%) within 3 days, 28 of 45 (62.2%) after 4-7 days (p=0.7318), 41 of 69 (59.4%) after 8-14 days (p=0.4651) and 6 of 18 (33.3%) with longer delays (p=0.0131). Median culture specimen collection time was 1 day within Drassanes Exprés vs 8 days within standard screening. Consequently, the overall culture yield was slightly higher within Drassanes Exprés (102/278, 36.6% vs 99/305, 32.5%; p=0.2934).

CONCLUSION

Reducing the interval between screening and collection of culture specimens increased N. gonorrhoeae recovery in extragenital samples. Implementing a same-day testing and notification programme increased collection of culture samples and culture yield in our setting, which may help AMR surveillance.

Genomics for public health and international surveillance of antimicrobial resistance

Historically, epidemiological investigation and surveillance for bacterial antimicrobial resistance (AMR) has relied on low-resolution isolate-based phenotypic analyses undertaken at local and national reference laboratories. Genomic sequencing has the potential to provide a far more high-resolution picture of AMR evolution and transmission, and is already beginning to revolutionise how public health surveillance networks monitor and tackle bacterial AMR. However, the routine integration of genomics in surveillance pipelines still has considerable barriers to overcome. In 2022, a workshop series and online consultation brought together international experts in AMR and pathogen genomics to assess the status of genomic applications for AMR surveillance in a range of settings. Here we focus on discussions around the use of genomics for public health and international AMR surveillance, noting the potential advantages of, and barriers to, implementation, and proposing recommendations from the working group to help to drive the adoption of genomics in public health AMR surveillance. These recommendations include the need to build capacity for genome sequencing and analysis, harmonising and standardising surveillance systems, developing equitable data sharing and governance frameworks, and strengthening interactions and relationships among stakeholders at multiple levels.

Neisseria gonorrhoeae antimicrobial susceptibility trends in Bangkok, Thailand, 2015-21: Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP)

Objectives

Rising antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global public health concern. Many ceftriaxone-resistant cases have been linked to Asia. In the WHO/CDC global Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP), we conducted AMR surveillance at two clinical sites in Bangkok, Thailand, 2015-21.

Methods

Urethral discharge samples, from males with urethral discharge and/or dysuria, were Gram-stained and cultured. ETEST was performed to determine AMR. EGASP MIC alert values, CLSI and EUCAST breakpoints were used.

Results

In 2015-21, gonococcal isolates were cultured from 1928 cases; most (64.1%) were males reporting having sex with females. The sensitivity and specificity of Gram-stained microscopy compared with culture for detection of gonococci were 97.5% and 96.6%, respectively. From 2015 to 2021, the azithromycin MIC90 increased from 0.125 to 1 mg/L, and the MIC90 of ceftriaxone and cefixime increased from 0.008 and ≤0.016 mg/L to 0.032 and 0.064 mg/L, respectively. Eight EGASP MIC alert values (in seven isolates) were identified. Five alert values were for cefixime (all resistant according to EUCAST breakpoints) and three for azithromycin (all resistant according to EUCAST breakpoints). The average annual resistance to ciprofloxacin during 2015-21 was 92%.

Conclusions

A continuous high susceptibility to ceftriaxone, Thailand's first-line gonorrhoea treatment, was found. However, the increasing MICs of ceftriaxone, cefixime and azithromycin are a substantial threat, especially considering these are the last remaining options for the treatment of gonorrhoea. To monitor AMR, continuous and quality-assured gonococcal AMR surveillance such as the Thai WHO/CDC EGASP, ideally including WGS, is imperative globally.

Genome-based epidemiology and antimicrobial resistance of Neisseria gonorrhoeae in Spain: A prospective multicentre study

BACKGROUND

Whole-genome sequencing (WGS) of Neisseria gonorrhoeae isolates combined with epidemiological and phenotypic data provides better understanding of population dynamics.

AIM

The objective of this study was to investigate the molecular epidemiology of N. gonorrhoeae isolates from three centres in Spain and determine associations of antimicrobial resistance.

METHODS

Genetic characterization was performed in 170 N. gonorrhoeae isolates. WGS was carried out with the HiSeq platform (Illumina). Genome assemblies were submitted to the PubMLST Neisseria database website to determine NG-MAST, MLST and NG-STAR. Antimicrobial resistance genes and point mutations were identified with PubMLST. Phylogenomic comparison was based on whole-genome single nucleotide polymorphism analysis.

RESULTS

Twenty-six MLST, 49 NG-MAST and 41 NG-STAR sequence types were detected, the most prevalent being MLST-ST9363 (27.1%), NG-MAST ST569 (12.4%) and NG-STAR ST193 (14.7%). Phylogenetic analysis identified 13 clusters comprising 69% of the isolates, with two of note: one involved cefixime-resistant isolates from Barcelona presenting a mosaic penA X and belonging to MLST-ST7363 and the other involved azithromycin-resistant isolates from Mallorca that possessed the C2611T mutation in the four 23S rRNA alleles belonging to MLST-ST1901.

CONCLUSION

The population of N. gonorrhoeae is quite heterogeneous in Spain. Our results agree with previous data published in Europe, albeit with some differences in distribution between regions. This study describes the circulation of two gonococcal populations with a specific resistance profile and sequence type in a specific geographic area. WGS is an effective tool for epidemiological surveillance of gonococcal infection and detection of resistance genes.

Safety Aspects and Rational Use of Single Intramuscular Dose Ceftriaxone: Clinical Insights on the Management of Uncomplicated Gonococcal Infections

Gonorrhea, a sexually transmitted infection caused by Neisseria gonorrhoeae, is a grave public health concern. Gonorrhea is the second most reported sexually transmitted infection worldwide. The treatment of uncomplicated gonococcal infections has evolved dramatically in response to the emergence of antimicrobial resistance. Multiple resistance mechanisms (for example, beta-lactamase production, antimicrobial efflux, and target site modification) exist, some of which may cause multidrug-resistance. Ceftriaxone was first recommended as an option for uncomplicated gonococcal infections in 1985, and it is now a mainstay of therapy in all clinical practice guidelines. Ceftriaxone has consistently shown high microbiologic cure rates in clinical trials, and it has demonstrated an excellent safety profile. Although its use may be limited in patients with hypersensitivity to penicillins, the risk of using ceftriaxone in such patients is overestimated. The emergence of reduced ceftriaxone susceptibility in N. gonorrhoeae, coupled with a lack of diverse treatment alternatives and the limited pipeline of new antimicrobials, is a significant threat to the treatment of gonorrhea.

[Urethritis-spectrum of pathogens, diagnostics and treatment]

A broad spectrum of bacteria, fungi, protozoa and viruses can cause urethritis. In particular, N. gonorrhoeae, C. trachomatis, M. genitalium and T. vaginalis are the focus of diagnostic considerations as classic pathogens associated with sexually transmitted infections (STI). A step-by-step procedure is needed to make a definitive diagnosis. Microscopy with a staining preparation provides an initial differentiation between gonoccocal and non-gonococcal urethritis in symptomatic men as a point-of-care (POC) test. Nucleic acid amplification technology (NAAT) is used for specific and sensitive pathogen detection and, as a multiplex diagnostic test, offers the possibility of detecting several organisms from the same sample. In addition, compared to culture, no vital organisms are required, which allows the collection and use of more diverse and less invasive biological samples (e.g. first stream urine in men or vaginal swabs). Susceptibility testing by culture remains essential for N. gonorrhoeae as resistance is emerging. The treatment of urethritis depends on the suspected or proven pathogen according to the current guidelines. Treatment failure can be caused by many factors (coinfection, lack of therapy adherence, reinfection or resistance of the pathogen) and requires a repeated diagnostic and therapeutic procedure and differentiated approach.

Economic evaluation of antimicrobial resistance in curable sexually transmitted infections; a systematic review and a case study

OBJECTIVE

To provide a summary of the economic and methodological evidence on capturing antimicrobial resistance (AMR) associated costs for curable sexually transmitted infections (STIs). To explore approaches for incorporating the cost of AMR within an economic model evaluating different treatment strategies for gonorrhoea, as a case study.

METHODS

A systematic review protocol was registered on PROSPERO (CRD42022298232). MEDLINE, EMBASE, CINAHL, Cochrane Library, International Health Technology Assessment Database, National Health Service Economic Evaluation Database, and EconLit databases were searched up to August 2022. Included studies were analysed, quality assessed and findings synthesised narratively. Additionally, an economic evaluation which incorporated AMR was undertaken using a decision tree model and primary data from a randomised clinical trial comparing gentamicin therapy with standard treatment (ceftriaxone). AMR was incorporated into the evaluation using three approaches-integrating the additional costs of treating resistant infections, conducting a threshold analysis, and accounting for the societal cost of resistance for the antibiotic consumed.

RESULTS

Twelve studies were included in the systematic review with the majority focussed on AMR in gonorrhoea. The cost of ceftriaxone resistant gonorrhoea and the cost of ceftriaxone sparing strategies were significant and related to the direct medical costs from persistent gonorrhoea infections, sequelae of untreated infections, gonorrhoea attributable-HIV transmission and AMR testing. However, AMR definition, the collection and incorporation of AMR associated costs, and the perspectives adopted were inconsistent or limited. Using the review findings, different approaches were explored for incorporating AMR into an economic evaluation comparing gentamicin to ceftriaxone for gonorrhoea treatment. Although the initial analysis showed that ceftriaxone was the cheaper treatment, gentamicin became cost-neutral if the clinical efficacy of ceftriaxone reduced from 98% to 92%. By incorporating societal costs of antibiotic use, gentamicin became cost-neutral if the cost of ceftriaxone treatment increased from £4.60 to £8.44 per patient.

CONCLUSIONS

Inclusion of AMR into economic evaluations may substantially influence estimates of cost-effectiveness and affect subsequent treatment recommendations for gonorrhoea and other STIs. However, robust data on the cost of AMR and a standardised approach for conducting economic evaluations for STI treatment which incorporate AMR are lacking, and requires further developmental research.