Stably high azithromycin resistance and decreasing ceftriaxone susceptibility in Neisseria gonorrhoeae in 25 European countries, 2016

Trends of Antimicrobial Susceptibility of Neisseria gonorrhoeae Isolates Between 2012 and 2023: Results From an Open Italian Cohort

BACKGROUND

Neisseria gonorrhoeae (Ng) is a public health priority because of the rapid evolution of antimicrobial resistance, the emergence of antibiotic resistance, and the absence of a vaccine against Ng. The aim of this study was to investigate trends in the minimum inhibitory concentration and resistance (R) or reduced susceptibility (DS) of Ng cases to ceftriaxone (CRO), azithromycin (AZM), tetracycline (TET), benzylpenicillin (PenG), and ciprofloxacin (CIP) during a 10-year period.

METHODS

We conducted a retrospective analysis on an open cohort of Ng cases diagnosed on rectal, urethral, and pharyngeal samples at San Raffaele Scientific Institute, between September 2012 and February 2023. Minimum inhibitory concentrations of antibiotics were determined by gradient-test strips. Bivariate linear regression models were applied on logarithmic minimum inhibitory concentrations values; Cochran-Armitage test was used to determine a linear trend in the proportions of resistant strains.

RESULTS

A total of 436 Ng isolates from 352 individuals were analyzed. Minimum inhibitory concentrations of CRO and PenG reduced over time ( P < 0.001, P = 0.030), AZM increased ( P = 0.001), and CIP and TET did not change ( P = 0.473, P = 0.272). The percentages of resistant strains were as follows: PenG, 89.9%; TET, 90.8%; CIP, 48.2%; AZM, and 4.4%. CRO-DS strains were 8.7%, and only 1 case of CRO-R was identified. The proportion of resistant strains increased over time for AZM ( P = 0.007), TET ( P = 0.001), and CIP ( P < 0.001), whereas it decreased for PenG ( P < 0.001) and CRO-DS/R strains ( P < 0.001).

CONCLUSIONS

Ng strains showed high susceptibility to CRO, although we identified cases of DS/R and observed high levels of susceptibility to AZM. Overall, the recommended primary regimen for Ng treatment was confirmed to be effective.

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.

Global analysis on the mutations associated with multidrug-resistant urogenital mycoplasmas and ureaplasmas infection: a systematic review and meta-analysis

BACKGROUND

The emergence of multidrug-resistant (MDR) strains of genital pathogens, notably Mycoplasma genitalium and Ureaplasma spp., constitutes a significant global threat today. The present study aimed to evaluate the prevalence and trend of changes in MDR mycoplasma and ureaplasma strains.

METHODS

An exhaustive search was performed across the ISI Web of Science, PubMed, Scopus, ScienceDirect, and Google Scholar databases to accumulate relevant studies without restrictions until April 2023. We used event rate and corresponding 95% confidence intervals to determine the frequency of resistance-related mutations and examine the trend of antibiotic resistance changes.

RESULTS

The data from 27 studies, including 24,662 patients across 14 countries, were evaluated. Out of the total studies, 20 focused on M. genitalium infections, and five on Ureaplasma spp. The frequency of resistance-associated mutations to macrolides, tetracyclines, and fluoroquinolones in clinical strains of M. genitalium was 43.5%, 13.1%, and 18.6%, respectively. The prevalence of M. genitalium strains with double resistance and MDR was 11.0% and 17.4%, respectively. The incidence of both double-drug-resistant and MDR strains was higher in the World Health Organization (WHO) Western Pacific Region than in European and American populations. For Ureaplasma strains, resistance-associated mutations to macrolides, tetracyclines, and fluoroquinolones were 40.8%, 25.7%, and 90.3%, respectively. The rate of antibiotic resistance was higher in the African population compared to the European and WHO Western Pacific Regions. The rate of MDR Ureaplasma infections was 13.2%, with a higher incidence in the African population compared to the WHO Western Pacific and European regions.

CONCLUSION

The proliferation and spread of MDR Mycoplasma and Ureaplasma strains present a significant public health challenge. The situation is indeed alarming, and the rising trend of MDR M. genitalium and MDR Ureaplasma infections suggests that therapies involving macrolides and fluoroquinolones may become less effective.

Pharmacodynamic evaluation of lefamulin in the treatment of gonorrhea using a hollow fiber infection model simulating Neisseria gonorrhoeae infections

The emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is seriously threatening the treatment and control of gonorrhea globally. Novel treatment options are essential, coupled with appropriate methods to pharmacodynamically examine the efficacy and resistance emergence of these novel drugs. Herein, we used our dynamic in vitro hollow fiber infection model (HFIM) to evaluate protein-unbound lefamulin, a semisynthetic pleuromutilin, against N. gonorrhoeae. Dose-range and dose-fractionation experiments with N. gonorrhoeae reference strains: WHO F (susceptible to all relevant antimicrobials), WHO X (extensively drug-resistant, including ceftriaxone resistance), and WHO V (high-level azithromycin resistant, and highest gonococcal MIC of lefamulin (2 mg/l) reported), were performed to examine lefamulin gonococcal killing and resistance development during treatment. The dose-range experiments, simulating a single oral dose of lefamulin based on human plasma concentrations, indicated that ≥1.2 g, ≥2.8 g, and ≥9.6 g of lefamulin were required to eradicate WHO F, X, and V, respectively. Dose-fractionation experiments, based on human lefamulin plasma concentrations, showed that WHO X was eradicated with ≥2.8 g per day when administered as q12 h (1.4 g twice a day) and with ≥3.6 g per day when administered as q8 h (1.2 g thrice a day), both for 7 days. However, when simulating the treatment with 5-10 times higher concentrations of free lefamulin in relevant gonorrhea tissues (based on urogenital tissues in a rat model), 600 mg every 12 h for 5 days (approved oral treatment for community-acquired bacterial pneumonia) eradicated all strains, and no lefamulin resistance emerged in the successful treatment arms. In many arms failing single or multiple dose treatments for WHO X, lefamulin-resistant mutants (MIC = 2 mg/l), containing an A132V amino acid substitution in ribosomal protein L3, were selected. Nevertheless, these lefamulin-resistant mutants demonstrated an impaired biofitness. In conclusion, a clinical study is warranted to elucidate the clinical potential of lefamulin as a treatment option for uncomplicated gonorrhea (as well as several other bacterial STIs).

Spontaneous clearance of asymptomatic anogenital and pharyngeal Neisseria gonorrhoeae: a secondary analysis from the NABOGO trial

INTRODUCTION

Spontaneous clearance of asymptomatic Neisseria gonorrhoeae (NG) does occur, but data are scarce. We aimed to assess spontaneous clearance among patients with asymptomatic anal, pharyngeal, vaginal and urethral NG infections who participated in the New AntiBiotic treatment Options for uncomplicated GOnorrhoea (NABOGO) trial. In addition, we assessed the determinants associated with spontaneous clearance.

METHODS

The NABOGO trial (Trial registration number: NCT03294395) was a randomised controlled, double-blind, single-centre trial assessing non-inferiority of ertapenem, gentamicin and fosfomycin to ceftriaxone for treatment of uncomplicated gonorrhoea. For asymptomatic NABOGO participants, we collected pre-enrolment and enrolment visit samples before trial medication was given. Spontaneous clearance was defined as a positive pre-enrolment nucleic acid amplification test (NAAT) result, followed by a negative NAAT at enrolment. We compared the median time between pre-enrolment and enrolment visits for patients who cleared spontaneously and for those who did not. Determinants of spontaneous clearance were assessed using logistic regression.

RESULTS

Thirty-two of 221 (14.5%) anal NG infections cleared spontaneously, 17 of 91 (18.7%) pharyngeal, 3 of 13 (23.1%) vaginal and 9 of 28 (32.1%) urethral NG infections. The median time between the pre-enrolment and enrolment visit was longer for patients who cleared their pharyngeal infection spontaneously compared with those who did not (median 8 days (IQR=7-11) vs 6 days (IQR=4-8), p=0.012); no determinants of clearance at other sites were identified. Overall, patients with more days between the pre-enrolment and enrolment visit were more likely to clear spontaneously (adjusted OR=1.06 per additional day, 95% CI 1.01 to 1.12). No association between location of NG infection and spontaneous clearance was found.

CONCLUSIONS

A significant proportion of asymptomatic patients cleared their NG infections spontaneously. Given these results, treatment of all NG infections after a one-time NAAT may be excessive, and more research on the natural history of NG is needed to improve antibiotic stewardship.

Significant increase in azithromycin "resistance" and susceptibility to ceftriaxone and cefixime in Neisseria gonorrhoeae isolates in 26 European countries, 2019

Background

The European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) performs annual sentinel surveillance of Neisseria gonorrhoeae susceptibility to therapeutically relevant antimicrobials across the European Union/European Economic Area (EU/EEA). We present the Euro-GASP results from 2019 (26 countries), linked to patient epidemiological data, and compared with data from previous years.

Methods

Agar dilution and minimum inhibitory concentration (MIC) gradient strip methodologies were used to determine the antimicrobial susceptibility (using EUCAST clinical breakpoints, where available) of 3239 N. gonorrhoeae isolates from 26 countries across the EU/EEA. Significance of differences compared with Euro-GASP results in previous years was analysed using Z-test and the Pearson's χ2 test was used to assess significance of odds ratios for associations between patient epidemiological data and antimicrobial resistance.

Results

European N. gonorrhoeae isolates collected between 2016 and 2019 displayed shifting MIC distributions for; ceftriaxone, with highly susceptible isolates increasing over time and occasional resistant isolates each year; cefixime, with highly-susceptible isolates becoming increasingly common; azithromycin, with a shift away from lower MICs towards higher MICs above the EUCAST epidemiological cut-off (ECOFF); and ciprofloxacin which is displaying a similar shift in MICs as observed for azithromycin. In 2019, two isolates displayed ceftriaxone resistance, but both isolates had MICs below the azithromycin ECOFF. Cefixime resistance (0.8%) was associated with patient sex, with resistance higher in females compared with male heterosexuals and men-who-have-sex-with-men (MSM). The number of countries reporting isolates with azithromycin MICs above the ECOFF increased from 76.9% (20/26) in 2016 to 92.3% (24/26) in 2019. Isolates with azithromycin MICs above the ECOFF (9.0%) were associated with pharyngeal infection sites. Following multivariable analysis, ciprofloxacin resistance remained associated with isolates from MSM and heterosexual males compared with females, the absence of a concurrent chlamydial infection, pharyngeal infection sites and patients ≥ 25 years of age.

Conclusions

Resistance to ceftriaxone and cefixime remained uncommon in EU/EEA countries in 2019 with a significant decrease in cefixime resistance observed between 2016 and 2019. The significant increase in azithromycin “resistance” (azithromycin MICs above the ECOFF) threatens the effectiveness of the dual therapy (ceftriaxone + azithromycin), i.e., for ceftriaxone-resistant cases, currently recommended in many countries internationally and requires close monitoring.

Antimicrobial susceptibility testing and molecular characterization of Neisseria gonorrhoeae in Tehran, Iran

Gonorrhea is a sexually transmitted infection occurring worldwide. Antimicrobial resistance (AMR) surveillance in Neisseria gonorrhoeae and associated molecular epidemiological studies are crucial to ascertain the spread of antibiotic-resistant and developing the local treatment guidelines. This study was performed to determine the antimicrobial susceptibility testing (AST) and molecular epidemiology of N. gonorrhoeae isolates in Tehran, Iran. During 1 July 2018-30 July 2020, a total of 500 urogenital (468 endocervical, 32 urethral) swabs were collected from patients with signs and symptoms of genitourinary infections presenting to two women's hospitals and one health center located center and south of Tehran. Specimens were cultured and examined for the presence of N. gonorrhoeae isolates by biochemical tests. MIC Test Strip determined the MICs of ceftriaxone, azithromycin, and ciprofloxacin. Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) was also performed. A total of 38 N. gonorrhoeae isolates were identified. The proportions of resistant N. gonorrhoeae isolates were as follows: ceftriaxone (MIC ≥0.125 μg/mL) 10.5% (4/38), azithromycin (MIC >1 μg/mL) 34% (13/38), and ciprofloxacin (MIC ≥1 μg/mL) 31.5% (12/38). In total, 25 different NG-MAST STs were identified. The STs comprised 1-4 isolates each, and the predominant ST was ST266 (n = 4). Our study demonstrates a diverse gonococcal population with high rates of resistance to azithromycin and evidence of resistance to ceftriaxone. The results have potential implications for antibiotic choice for the gonococcal treatment and highlight the need to broaden gonococcal AMR monitoring in Iran.

Surveillance systems to monitor antimicrobial resistance in Neisseria gonorrhoeae: a global, systematic review, 1 January 2012 to 27 September 2020

Background

Effective surveillance of antimicrobial resistance (AMR) in Neisseria gonorrhoeae is required for the early detection of resistant strains and to ensure that treatment guidelines are appropriate for the setting in which they are implemented. AMR in N. gonorrhoeae has been identified as a global health threat.

Aim

We performed a systematic review to identify and describe surveillance systems targeting AMR in N. gonorrhoeae.

Methods

We searched Medline, PubMed, Global Health, EMBASE, CINAHL, Web of Science and ProQuest databases and grey literature between 1 January 2012 and 27 September 2020. Surveillance systems were defined as the continuous, systematic collection, analysis and interpretation of N. gonorrhoeae resistance data. The key components of surveillance systems were extracted, categorised, described and summarised.

Results

We found 40 publications reporting on N. gonorrhoeae AMR surveillance systems in 27 countries and 10 multi-country or global surveillance reports. The proportion of countries with surveillance systems in each of the WHO's six regions ranged from one of 22 countries in the Eastern Mediterranean and five of 54 in Africa, to three of 11 countries in South East Asia. Only four countries report systems which are both comprehensive and national. We found no evidence of a current surveillance system in at least 148 countries. Coverage, representativeness, volume, clinical specimen source, type and epidemiological information vary substantially and limit interpretability and comparability of surveillance data for public health action.

Conclusion

Globally, surveillance for N. gonorrhoeae AMR is inadequate and leaves large populations vulnerable to a major public health threat.

The European response to control and manage multi- and extensively drug-resistant Neisseria gonorrhoeae

Because cefixime and ceftriaxone resistance in Neisseria gonorrhoeae and gonorrhoea treatment failures were increasing, a response plan to control and manage multidrug-resistant N. gonorrhoeae (MDR-NG) in Europe was published in 2012. The three main areas of the plan were to: (i) strengthen surveillance of antimicrobial resistance (AMR), (ii) implement monitoring of treatment failures and (iii) establish a communication strategy to increase awareness and disseminate AMR results. Since 2012, several additional extensively drug-resistant N. gonorrhoeae (XDR-NG) strains have emerged, and strains with high-level ceftriaxone resistance spread internationally. This prompted an evaluation and review of the 2012 European Centre for Disease Prevention and Control (ECDC) response plan, revealing an overall improvement in many aspects of monitoring AMR in N. gonorrhoeae; however, treatment failure monitoring was a weakness. Accordingly, the plan was updated in 2019 to further support European Union/European Economic Area (EU/EEA) countries in controlling and managing the threat of MDR/XDR-NG in Europe through further strengthening of AMR surveillance and clinical management including treatment failure monitoring. The plan will be assessed biennially to ensure its effectiveness and its value. Along with prevention, diagnostic, treatment and epidemiological surveillance strategies, AMR surveillance is essential for effective control of gonorrhoea.

Reliability of Genetic Alterations in Predicting Ceftriaxone Resistance in Neisseria gonorrhoeae Globally

Antimicrobial resistance in N. gonorrhoeae is increasing globally, and ceftriaxone is the recommended treatment for empirical therapy in most settings. Developing molecular assays to detect decreased ceftriaxone susceptibility is critical. Using PathogenWatch, a public database of N. gonorrhoeae genomes, antibiotic susceptibility data and DNA sequences of different genes associated with ceftriaxone resistance were extracted. That information was used to determine the sensitivity and specificity of different molecular markers and algorithms to predict decreased susceptibility to ceftriaxone. A total of 12,943 N. gonorrhoeae genomes were extracted from the PathogenWatch database, of which 9,540 genomes were used in the analysis. The sensitivity and specificity of specific molecular markers and algorithms were largely consistent with prior reports. Small variation (<10%) in either sensitivity or specificity occurred. Certain algorithms using different molecular markers at various prevalence of decreased ceftriaxone susceptibility identified a potentially clinically useful range of positive and negative predictive values. We validated previously described mutations and algorithms in a large public database containing a global collection of N. gonorrhoeae genomes. Certain mutations and algorithms resulted in sensitivity and specificity values consistent with those of prior studies. Further research is needed to integrate these markers and algorithms into the development of molecular assays to predict decreased ceftriaxone susceptibility. IMPORTANCE Antimicrobial resistance in Neisseria gonorrhoeae (N. gonorrhoeae), the causative agent of gonorrhea, is rising globally. Ceftriaxone is the last remaining antibiotic for empirical treatment of gonorrhea. Developing molecular tests to predict ceftriaxone resistance can help to improve detection and surveillance of ceftriaxone resistance. Here, we utilized PathogenWatch, a public global online database of N. gonorrhoeae genomes, to evaluate different genetic markers in predicting decreased susceptibility to ceftriaxone. We compiled MICs for ceftriaxone from the PathogenWatch database and used a computational approach to extract all the genetic markers from the genomic data. We determined the sensitivity and specificity for predicting decreased ceftriaxone susceptibility among several combinations of genetic markers. We identified several combinations of genetic markers with high predictive values for decreased susceptibility to ceftriaxone. These combinations of genetic markers might be promising candidates for future molecular tests to predict ceftriaxone resistance.

Pharmacodynamic Evaluation of Zoliflodacin Treatment of Neisseria gonorrhoeae Strains With Amino Acid Substitutions in the Zoliflodacin Target GyrB Using a Dynamic Hollow Fiber Infection Model

Novel antimicrobials for effective treatment of uncomplicated gonorrhea are essential, and the first-in-class, oral spiropyrimidinetrione DNA gyrase B inhibitor zoliflodacin appears promising. Using our newly developed Hollow Fiber Infection Model (HFIM), the pharmacodynamics of zoliflodacin was examined. A clinical zoliflodacin-susceptible N. gonorrhoeae strain, SE600/18 (harbouring a GyrB S467N amino acid substitution; MIC = 0.25 mg/L), and SE600/18-D429N (zoliflodacin-resistant mutant with a second GyrB substitution, D429N, selected in the HFIM experiments; zoliflodacin MIC = 2 mg/L), were examined. Dose-range experiments, simulating zoliflodacin single oral dose regimens of 0.5, 1, 2, 3, and 4 g, were performed for SE600/18. For SE600/18-D429N, dose-range experiments, simulating zoliflodacin single oral 2, 3, 4, and 6 g doses, and zoliflodacin oral dose-fractionation experiments with 4, 6, and 8 g administered as q12 h were performed. Both strains grew well in the untreated HFIM growth control arms and mostly maintained growth at 1010-1011 CFU/ml for 7 days. Zoliflodacin 3 and 4 g single dose oral regimens successfully eradicated SE600/18 and no growth was recovered during the 7-days experiments. However, the single oral 0.5, 1, and 2 g doses failed to eradicate SE600/18, and zoliflodacin-resistant populations with a GyrB D429N substitution were selected with all these doses. The zoliflodacin-resistant SE600/18-D429N mutant was not eradicated with any examined treatment regimen. However, this in vitro-selected zoliflodacin-resistant mutant was substantially less fit compared to the zoliflodacin-susceptible SE600/18 parent strain. In conclusion, the rare clinical gonococcal strains with GyrB S467N substitution are predisposed to develop zoliflodacin resistance and may require treatment with zoliflodacin ≥3 g. Future development may need to consider the inclusion of diagnostics directed at identifying strains resistant or predisposed to resistance development at a population level and to strengthen surveillance (phenotypically and genetically), and possibly also at the patient level to guide treatment.

Management of Neisseria gonorrhoeae in the United States: Summary of Evidence From the Development of the 2020 Gonorrhea Treatment Recommendations and the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infection Treatment Guidelines

INTRODUCTION

Neisseria gonorrhoeae has developed resistance to all first-line recommended therapies, making gonococcal antimicrobial resistance a major public health concern given limited antibiotic options currently and an even smaller antimicrobial development pipeline. Since the release of the Centers for Disease Control and Prevention (CDC) 2015 STD Treatment Guidelines, azithromycin, part of the 2015 dual-drug treatment regimen, has had a rapid rise in resistance. The 2020 CDC Gonorrhea Treatment Recommendations and the 2021 Sexually Transmitted Infections (STI) Treatment Guidelines were developed weighing the priorities of treating the individual, protecting the population, and preventing antimicrobial resistance.

METHODS

Gonorrhea subject matter experts (SME) generated 8 key questions and conducted a literature review of updated data from 2013 to 2019 on gonorrhea antimicrobial resistance, treatment failures, clinical trials, and other key topics. More than 2200 abstracts were assessed, and 248 clinically relevant articles were thoroughly reviewed. SMEs also evaluated N gonorrhoeae antimicrobial resistance data from the Gonococcal Isolate Surveillance Project (GISP).

EVIDENCE

Although there have been reports of ceftriaxone treatment failures internationally, GISP data suggest that ceftriaxone minimal inhibitory concentrations (MICs) have remained stable in the United States, with < 0.1% exhibiting an "alert value" MIC (> 0.25 mcg/mL). However, GISP documented a rapid rise in the proportion of isolates with an elevated MIC (≥ 2.0 mcg/mL) to azithromycin-nearly 5% in 2018. At the same time, new pharmacokinetic/pharmacodynamic data are available, and there is greater recognition of the need for antimicrobial stewardship.

SUMMARY

The 2021 CDC STI Treatment Guidelines now recommend 500mg ceftriaxone intramuscularly once for the treatment of uncomplicated gonorrhea at all anatomic sites. If coinfection with chlamydia has not been excluded, cotreatment with doxycycline 100mg twice daily for 7 days should be added. Few alternative therapies exist for persons with cephalosporin allergies; there are no recommended alternative therapies for N gonorrhoeae infection of the throat.

Antimicrobial resistance prediction in Neisseria gonorrhoeae: Current status and future prospects

INTRODUCTION

Several nucleic acid amplification tests (NAATs), mostly real-time PCRs, to detect antimicrobial resistance (AMR) determinants and predict AMR in Neisseria gonorrhoeae are promising, and some may be ready to apply at the point-of-care (POC), but important limitations remain with most NAATs. Next-generation sequencing (NGS) can overcome many of these limitations.Areas covered: Recent advances, with main focus on publications since 2017, in the development and use of NAATs and NGS to predict gonococcal AMR for surveillance and clinical use, and pros and cons of these tests as well as future perspectives for appropriate use of molecular AMR prediction for N. gonorrhoeae.Expert Commentary: NAATs and/or NGS for AMR prediction should supplement culture-based AMR surveillance, which will remain because it detects also AMR due to unknown AMR determinants, and translation into POC tests is imperative for the end-goal of individualized treatment, sparing ceftriaxone±azithromycin. Several challenges for direct testing of clinical, especially pharyngeal, specimens and for accurate prediction of cephalosporins and azithromycin resistance, especially using NAATs, remain. The choice of AMR prediction assay needs to carefully consider the intended use of the assay; limitations intrinsic to the AMR prediction technology, algorithms and specific to chosen methodology; specimen types analyzed; and cost-effectiveness.

Neisseria gonorrhoeae antimicrobial resistance in Spain: a prospective multicentre study

OBJECTIVES

Gonococcal infection is one of the most reported sexually transmitted infections and antimicrobial resistance in Neisseria gonorrhoeae (NG) is challenging for the treatment of this infection. This observational study aimed to describe antimicrobial resistance of NG and epidemiological data from patients with gonococcal infection in eight regions of Spain, for updating the local therapeutic guidelines.

METHODS

MICs of penicillin, cefixime, ceftriaxone, azithromycin, ciprofloxacin, fosfomycin and gentamicin were determined by Etest for all NG isolates recovered from 1 April 2018 to 30 September 2019 from 10 hospitals in Spain. Resistance determinants were identified using logistic regression analysis. Differences with a P value <0.05 were considered statistically significant.

RESULTS

Antimicrobial susceptibility testing was performed for 2571 gonococci isolated from 2429 patients. 44.5% (945/2124) of patients were MSM. The resistance rate to extended-spectrum cephalosporins was low, with 0.2% (6/2561) of isolates resistant to ceftriaxone and 1.7% (44/2517) of isolates resistant to cefixime. The overall azithromycin resistance rate was 12.1% (310/2560), but differed greatly depending on the area. 56.2% (1366/2429) of the strains studied were ciprofloxacin resistant. MIC50 and MIC90 values of gentamicin and fosfomycin were 4 and 8 mg/L and 24 and 48 mg/L, respectively.

CONCLUSIONS

Our study shows that NG susceptibility to extended-spectrum cephalosporins remains high in Spain. The azithromycin resistance rate questions the suitability of dual therapy. This study provides data of interest for updating the national treatment guidelines and highlights the need to develop and implement a national sentinel gonococcal antimicrobial susceptibility programme.

Characterization of 2 Neisseria gonorrhoeae Strains With High-Level Azithromycin Resistance Isolated in 2015 and 2018 in Japan

ABSTRACT

We identified and characterized the first 2 Neisseria gonorrhoeae strains with high-level azithromycin resistance isolated in Japan. These were in the clade of ceftriaxone- and azithromycin-resistant strains isolated in Australia and the United Kingdom. The multilocus sequence typing, N. gonorrhoeae multiantigen sequence typing, and N. gonorrhoeae sequence typing for antimicrobial resistance types of these strains were found in gonococci from eastern Asia.

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

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

Genomic epidemiology of Neisseria gonorrhoeae elucidating the gonococcal antimicrobial resistance and lineages/sublineages across Brazil, 2015-16

OBJECTIVES

Neisseria gonorrhoeae antimicrobial resistance (AMR) surveillance is imperative internationally, but only eight (22.9%) countries in the WHO Region of the Americas reported complete AMR data to the WHO Global Gonococcal Antimicrobial Surveillance Program (WHO GASP) in 2016. Genomic studies are ideal for enhanced understanding of gonococcal populations, including the spread of AMR strains. To elucidate the circulating gonococcal lineages/sublineages, including their AMR determinants, and the baseline genomic diversity among gonococcal strains in Brazil, we conducted WGS on 548 isolates obtained in 2015-16 across all five macroregions in Brazil.

METHODS

A total of 548 gonococcal isolates cultured across Brazil in 2015-16 were genome sequenced. AMR was determined using agar dilution and/or Etest. Genome sequences of isolates from Argentina (n = 158) and the 2016 WHO reference strains (n = 14) were included in the analysis.

RESULTS

We found 302, 68 and 214 different NG-MAST, MLST and NG-STAR STs, respectively. The phylogenomic analysis identified one main antimicrobial-susceptible lineage and one AMR lineage, which was divided into two sublineages with different AMR profiles. Determination of NG-STAR networks of clonal complexes was shown as a new and valuable molecular epidemiological analysis. Several novel mosaic mtrD (and mtrR and mtrE) variants associated with azithromycin resistance were identified.

CONCLUSIONS

We describe the first genomic baseline data to support the Brazilian GASP. The high prevalence of resistance to ciprofloxacin, tetracycline and benzylpenicillin, and the high number of isolates with mosaic penA and azithromycin resistance mutations, should prompt continued and strengthened AMR surveillance, including WGS, of N. gonorrhoeae in Brazil.

Antimicrobial resistance and molecular epidemiological typing of Neisseria gonorrhoeae isolates from Kyrgyzstan in Central Asia, 2012 and 2017

Background

Gonorrhoea and antimicrobial resistance (AMR) in Neisseria gonorrhoeae are significant public health concerns globally. Nearly no gonococcal AMR data are available from Central Asia, and no data from Kyrgyzstan has been published. We examined, for the first time, AMR and molecular epidemiology of N. gonorrhoeae isolates cultured in Kyrgyzstan in 2012 and 2017, in order to inform refinements of the Kyrgyz national gonorrhoea management guidelines.

Methods

N. gonorrhoeae isolates cultured in 2012 (n = 84) and 2017 (n = 72) in Kyrgyzstan were examined. MICs of nine antimicrobials were determined using Etest and, where available, clinical breakpoints from the EUCAST were applied. N. gonorrhoeae multiantigen sequence typing (NG-MAST) was also performed.

Results

The overall resistance levels were high to ciprofloxacin (88.5%), tetracycline (56.9%), benzylpenicillin (39.1%), and kanamycin (4.7%). Resistance to cefixime (0.6%, n = 1 isolate), azithromycin (0.6%, n = 1), and gentamicin (0.6%, n = 1) was rare. No resistance to ceftriaxone or spectinomycin was found. However, the proportion of isolates with decreased susceptibility (MIC = 0.125 mg/L) to ceftriaxone and cefixime was 12.8 and 11.5%, respectively. Gonococcal isolates were assigned 69 sequence types, of which 52 (75.4%) were new.

Conclusions

The gonococcal population in Kyrgyzstan in 2012 and 2017 showed a high genetic diversity. Ceftriaxone, 500–1000 mg, in combination with azithromycin 2 g or doxycycline, particularly when chlamydial infection has not been excluded, should be recommended as empiric first-line treatment. Spectinomycin 2 g could be an alternative treatment, and given with azithromycin 2 g if pharyngeal gonorrhoea has not been excluded. Fluoroquinolones, aminoglycosides, benzylpenicillin, or tetracyclines should not be used for empiric treatment of gonorrhoea in Kyrgyzstan. Timely updating and high compliance to national gonorrhoea treatment guidelines based on quality-assured AMR data is imperative. Expanded and improved gonococcal AMR surveillance in Kyrgyzstan is crucial.

Gentamicin, azithromycin and ceftriaxone in the treatment of gonorrhoea: the relationship between antibiotic MIC and clinical outcome

OBJECTIVES

To investigate the relationship between MIC and clinical outcome in a randomized controlled trial that compared gentamicin 240 mg plus azithromycin 1 g with ceftriaxone 500 mg plus azithromycin 1 g. MIC analysis was performed on Neisseria gonorrhoeae isolates from all participants who were culture positive before they received treatment.

METHODS

Viable gonococcal cultures were available from 279 participants, of whom 145 received ceftriaxone/azithromycin and 134 received gentamicin/azithromycin. Four participants (6 isolates) and 14 participants (17 isolates) did not clear infection in the ceftriaxone/azithromycin and gentamicin/azithromycin arms, respectively. MICs were determined by Etest on GC agar base with 1% Vitox. The geometric mean MICs of azithromycin, ceftriaxone and gentamicin were compared using logistic and linear regression according to treatment received and N. gonorrhoeae clearance.

RESULTS

As the azithromycin MIC increased, gentamicin/azithromycin treatment was less effective than ceftriaxone/azithromycin at clearing N. gonorrhoeae. There was a higher geometric mean MIC of azithromycin for isolates from participants who had received gentamicin/azithromycin and did not clear infection compared with those who did clear infection [ratio 1.95 (95% CI 1.28-2.97)], but the use of categorical MIC breakpoints did not accurately predict the treatment response. The geometric mean MIC of azithromycin was higher in isolates from the pharynx compared with genital isolates.

CONCLUSIONS

We found that categorical resistance to azithromycin or ceftriaxone in vitro, and higher gentamicin MICs in the absence of breakpoints, were poorly predictive of treatment failure.

Antimicrobial resistance in Neisseria gonorrhoeae isolates and gonorrhoea treatment in the Republic of Belarus, Eastern Europe, 2009-2019

Background

Limited antimicrobial resistance (AMR) data for Neisseria gonorrhoeae are available in Eastern Europe. We investigated AMR in N. gonorrhoeae isolates in the Republic of Belarus from 2009 to 2019, antimicrobial treatment recommended nationally, and treatment given to patients with gonorrhoea.

Methods

N. gonorrhoeae isolates (n = 522) cultured in three regions of Belarus in 2009–2019 were examined. Determination of minimum inhibitory concentrations (MICs) of eight antimicrobials was performed using Etest. Resistance breakpoints from the European Committee on Antimicrobial Susceptibility Testing were applied where available. A Nitrocefin test identified β-lactamase production. Gonorrhoea treatment for 1652 patients was also analysed. Statistical significance was determined by the Z-test, Fisher’s exact test, or Mann-Whitney U test with p-values of < 0.05 indicating significance.

Results

In total, 27.8% of the N. gonorrhoeae isolates were resistant to tetracycline, 24.7% to ciprofloxacin, 7.0% to benzylpenicillin, 2.7% to cefixime, and 0.8% to azithromycin. No isolates were resistant to ceftriaxone, spectinomycin, or gentamicin. However, 14 (2.7%) isolates had a ceftriaxone MIC of 0.125 mg/L, exactly at the resistance breakpoint (MIC > 0.125 mg/L). Only one (0.2%) isolate, from 2013, produced β-lactamase. From 2009 to 2019, the levels of resistance to ciprofloxacin and tetracycline were relatively high and stable. Resistance to cefixime was not identified before 2013 but peaked at 22.2% in 2017. Only sporadic isolates with resistance to azithromycin were found in 2009 (n = 1), 2012 (n = 1), and 2018–2019 (n = 2). Overall, 862 (52.2%) patients received first-line treatment according to national guidelines (ceftriaxone 1 g). However, 154 (9.3%) patients received a nationally recommended alternative treatment (cefixime 400 mg or ofloxacin 400 mg), and 636 (38.5%) were given non-recommended treatment.

Conclusions

The gonococcal resistance to ciprofloxacin and tetracycline was high, however, the resistance to azithromycin was low and no resistance to ceftriaxone was identified. Ceftriaxone 1 g can continuously be recommended as empiric first-line gonorrhoea therapy in Belarus. Fluoroquinolones should not be prescribed for treatment if susceptibility has not been confirmed by testing. Timely updating and high compliance with national evidence-based gonorrhoea treatment guidelines based on quality-assured AMR data are imperative. The need for continued, improved and enhanced surveillance of gonococcal AMR in Belarus is evident.

Pharmacodynamic Evaluation of Dosing, Bacterial Kill, and Resistance Suppression for Zoliflodacin Against Neisseria gonorrhoeae in a Dynamic Hollow Fiber Infection Model

Antimicrobial resistance in Neisseria gonorrhoeae is threatening the treatment and control of gonorrhea globally, and new treatment options are imperative. Utilizing our dynamic in vitro hollow fiber infection model (HFIM), we examined the pharmacodynamics of the first-in-class spiropyrimidinetrione (DNA gyrase B inhibitors), zoliflodacin, against the N. gonorrhoeae reference strains World Health Organization F (susceptible to all relevant antimicrobials) and WHO X (extensively drug resistant, including resistance to ceftriaxone) over 7 days. Dose-range experiments with both strains, simulating zoliflodacin single oral dose regimens of 0.5-8 g, and dose-fractionation experiments with WHO X, simulating zoliflodacin oral dose therapy with 1-4 g administered as q12 h and q8 h for 24 h, were performed. A kill-rate constant that reflected a rapid bacterial kill during the first 6.5 h for both strains and all zoliflodacin doses was identified. In the dose-range experiments, the zoliflodacin 2-8 g single-dose treatments successfully eradicated both WHO strains, and resistance to zoliflodacin was not observed. However, zoliflodacin as a single 0.5 g dose failed to eradicate both WHO strains, and a 1 g single dose failed to eradicate WHO X in one of two experiments. The zoliflodacin 1 g/day regimen also failed to eradicate WHO X when administered as two and three divided doses given at q12 h and q8 h in the dose-fractionation studies, respectively. All failed regimens selected for zoliflodacin-resistant mutants. In conclusion, these data demonstrate that zoliflodacin should be administered at >2 g as a single oral dose to provide effective killing and resistance suppression of N. gonorrhoeae. Future studies providing pharmacokinetic data for zoliflodacin (and other gonorrhea therapeutic antimicrobials) in urogenital and extragenital infection sites, particularly in the pharynx, and evaluation of gonococcal strains with different gyrB mutations would be important.

Torsade de pointes associated with chloroquine, hydroxychloroquine, and azithromycin: a retrospective analysis of individual case safety reports from VigiBase

PURPOSE

To analyze the cases of torsade de pointes (TdP) and related symptoms reported in association with chloroquine (CQ), hydroxychloroquine (HCQ), and azithromycin (AZT) to the World Health Organization (WHO) global database of individual case safety reports (ICSRs) for drug monitoring (VigiBase) using qualitative and quantitative pharmacovigilance approaches.

METHODS

The main characteristics of the ICSRs reporting TdP with CQ, HCQ, and AZT have been summarized. Co-reported drugs with risk to cause QT prolongation have been described. Reporting odds ratios (RORs) as a measure of disproportionality for reported TdP and individual drugs have been calculated.

RESULTS

One hundred seventy ICSRs reporting TdP in association with the drugs of interest were identified (CQ: 11, HCQ: 31, CQ + HCQ: 1, HCQ + AZT: 27, AZT: 100). From these, 41 (24.3%) were received during the pandemic period (December 2019 to February 2021). The median age of the patients was 63, 53, and 63 years old for CQ, HCQ, and AZT, respectively. Reports included concomitant use of other QT-prolonging drugs (CQ 25.0%, HCQ 71.2%, AZT 64.6%). A proportion of the cases were fatal (CQ 25.0%, HCQ 8.6%, AZT 16.1%). Increased disproportionality has been found for the individual drugs and TdP: CQ (ROR: 7.41, 95% confidence interval (CI): 3.82, 12.96), HCQ (ROR: 8.49, 95% CI: 6.57, 10.98), azithromycin (ROR: 8.06, 95% CI: 6.76, 9.61). Disproportionality was also found for other related symptoms, Standardized MedDRA Query for torsade de pointes/QT prolongation (narrow): CQ (ROR: 11.95, 95% CI: 10.04-14.22); HCQ (ROR: 20.43, 95% CI: 19.13, 21.83), AZT (ROR: 7.78, 95% CI: 7.26, 8.34).

CONCLUSIONS

The prescription of CQ, HCQ, and AZT should be restricted to therapeutic indications with established positive benefit/risk profile. Doctors and patients should be aware of this potential adverse reaction especially when several risk factors are present.

[Increased infections by herpes simplex virus type 1 and polymicrobials of the genital tract, in the general population of a Spanish middle city]

Introducción

Las infecciones por genitopatógenos son un motivo de consulta frecuente en Atención Primaria y en las especialidades de Enfermedades Infecciosas, Urología, Ginecología y Dermatología. Las causas más comunes son los microorganismos oportunistas y los responsables de las infecciones de transmisión sexual asociadas a prácticas sin protección. El objetivo de este trabajo es determinar los microorganismos que causan estas infecciones en los pacientes atendidos en el Hospital Universitario Virgen de las Nieves de Granada y la sensibilidad a los antibióticos de Neisseria gonorrhoeae.

Material y métodos

Se realizó un estudio transversal y retrospectivo, en el que se incluyeron los resultados emitidos, entre enero de 2018 y diciembre de 2019, en el Laboratorio de Microbiología a partir de todos los episodios estudiados mediante procedimiento normalizados de trabajo.

Resultados:

Los microorganismos más frecuentemente detectados fueron Gardnerella vaginalis (23,81%) seguido de Candida spp. (20,9%), sobre todo en mujeres, N. gonorrhoeae (11,36%) y Ureaplasma urealyticum (11,99%), sobre todo en hombres. En multitud de ocasiones se presentaron de forma combinada. En cuanto a los virus del herpes simple, en hombres la infección por ambas especies tuvo una presencia similar (50%), mientras que en mujeres el tipo 1 fue más prevalente (76,52%). Los antibióticos más activos frente a N. gonorrhoeae fueron cefotaxima (98%) y cefixima (100%), siendo poco activo tetraciclina (39,02%).

Conclusiones

Los patógenos más frecuentes correspondieron a aquellos que han causado habitualmente infecciones en las mujeres, aunque N. gonorrhoeae fue el más frecuente en varones y las infecciones mixtas no son un hallazgo casual. Las infecciones por VHS-1 fueron más frecuentes que por VHS-2, lo cual confirma la tendencia de un cambio en la epidemiología del herpes genital.

Associations between antimicrobial susceptibility/resistance of Neisseria gonorrhoeae isolates in European Union/European Economic Area and patients' gender, sexual orientation and anatomical site of infection, 2009-2016

BACKGROUND

The emergence and spread of antimicrobial resistance (AMR) in Neisseria gonorrhoeae, nationally and internationally, is a serious threat to the management and control of gonorrhoea. Limited and conflicting data regarding the epidemiological drivers of gonococcal AMR internationally have been published. We examined the antimicrobial susceptibility/resistance of gonococcal isolates (n = 15,803) collected across 27 European Union/European Economic Area (EU/EEA) countries in 2009-2016, in conjunction to epidemiological and clinical data of the corresponding patients, to elucidate associations between antimicrobial susceptibility/resistance and patients' gender, sexual orientation and anatomical site of infection.

METHODS

In total, 15,803 N. gonorrhoeae isolates from the European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP), 2009-2016, were examined. Associations between gonococcal susceptibility/resistance and patients' gender, sexual orientation and anatomical site of infection were investigated using univariate and multivariate logistic regression analysis. Statistical significance was determined by Pearson χ2-test or Fisher's exact test with two-tailed p-values of < 0.05 indicating significance.

RESULTS

The overall gonococcal resistance from 2009 to 2016 was 51.7% (range during the years: 46.5-63.5%), 7.1% (4.5-13.2%), 4.3% (1.8-8.7%), and 0.2% (0.0-0.5%) to ciprofloxacin, azithromycin, cefixime, and ceftriaxone, respectively. The level of resistance combined with decreased susceptibility to ceftriaxone was 10.2% (5.7-15.5%). Resistance to cefixime and ciprofloxacin, and resistance combined with decreased susceptibility to ceftriaxone were positively associated with urogenital infections and heterosexual males, males with sexual orientation not reported and females (except for ciprofloxacin), i.e. when compared to men-who-have-sex-with-men (MSM). Azithromycin resistance was positively associated with heterosexual males, but no association was significant regarding anatomical site of infection.

CONCLUSIONS

Overall, sexual orientation was the main variable associated with gonococcal AMR. Strongest positive associations were identified with heterosexual patients, particularly males, and not MSM. To provide evidence-based understanding and mitigate gonococcal AMR emergence and spread, associations between antimicrobial susceptibility/resistance and patients' gender, sexual orientation and anatomical site of infection need to be further investigated in different geographic settings. In general, these insights will support identification of groups at increased risk and targeted public health actions such as intensified screening, 3-site testing using molecular diagnostics, sexual contact tracing, and surveillance of treatment failures.

Using rapid point-of-care tests to inform antibiotic choice to mitigate drug resistance in gonorrhoea

Background

The first cases of extensively drug resistant gonorrhoea were recorded in the United Kingdom in 2018. There is a public health need for strategies on how to deploy existing and novel antibiotics to minimise the risk of resistance development. As rapid point-of-care tests (POCTs) to predict susceptibility are coming to clinical use, coupling the introduction of an antibiotic with diagnostics that can slow resistance emergence may offer a novel paradigm for maximising antibiotic benefits. Gepotidacin is a novel antibiotic with known resistance and resistance-predisposing mutations. In particular, a mutation that confers resistance to ciprofloxacin acts as the ‘stepping-stone’ mutation to gepotidacin resistance.

Aim

To investigate how POCTs detecting Neisseria gonorrhoeae resistance mutations for ciprofloxacin and gepotidacin can be used to minimise the risk of resistance development to gepotidacin.

Methods

We use individual-based stochastic simulations to formally investigate the aim.

Results

The level of testing needed to reduce the risk of resistance development depends on the mutation rate under treatment and the prevalence of stepping-stone mutations. A POCT is most effective if the mutation rate under antibiotic treatment is no more than two orders of magnitude above the mutation rate without treatment and the prevalence of stepping-stone mutations is 1–13%.

Conclusion

Mutation frequencies and rates should be considered when estimating the POCT usage required to reduce the risk of resistance development in a given population. Molecular POCTs for resistance mutations and stepping-stone mutations to resistance are likely to become important tools in antibiotic stewardship.

Susceptibility Trends of Zoliflodacin against Multidrug-Resistant Neisseria gonorrhoeae Clinical Isolates in Nanjing, China, 2014 to 2018

Previously, we reported the potent activity of a novel spiropyrimidinetrione, zoliflodacin, against Neisseria gonorrhoeae isolates collected in 2013 from symptomatic men in Nanjing, China. Here, we investigated trends of susceptibilities to zoliflodacin in 986 isolates collected from men between 2014 and 2018. N. gonorrhoeae isolates were tested for susceptibility to zoliflodacin and seven other antibiotics. Mutations in the gyrA, gyrB, parC, parE, and mtrR genes were determined by PCR and sequencing. The MICs of zoliflodacin ranged from ≤0.002 to 0.25 mg/liter; the overall MIC50 and MIC90 were 0.06 mg/liter and 0.125 mg/liter, respectively, in 2018, increasing 2-fold from 2014. However, the percentage of isolates with lower zoliflodacin MICs declined in each year sequentially, while the percentage with higher MICs increased yearly (P ≤ 0.00001). All isolates were susceptible to spectinomycin but resistant to ciprofloxacin (MIC ≥ 1 mg/liter); 21.2% (209/986) were resistant to azithromycin (≥1 mg/liter), 43.4% (428/986) were penicillinase-producing N. gonorrhoeae (PPNG), 26.9% (265/986) were tetracycline-resistant N. gonorrhoeae (TRNG), and 19.4% (191/986) were multidrug-resistant (MDR) isolates. 202 isolates with the lowest (≤0.002 to 0.015 mg/liter) and highest (0.125 to 0.25 mg/liter) zoliflodacin MICs were quinolone resistant with double or triple mutations in gyrA; 193/202 (95.5%) also had mutations in parC There were no D429N/A and/or K450T mutations in GyrB identified in the 143 isolates with higher zoliflodacin MICs; an S467N mutation in GyrB was identified in one isolate. We report that zoliflodacin continues to have excellent in vitro activity against clinical gonococcal isolates, including those with high-level resistance to ciprofloxacin, azithromycin, and extended-spectrum cephalosporins.

Neisseria gonorrhoeae clustering to reveal major European whole-genome-sequencing-based genogroups in association with antimicrobial resistance

Neisseria gonorrhoeae, the bacterium responsible for the sexually transmitted disease gonorrhoea, has shown an extraordinary ability to develop antimicrobial resistance (AMR) to multiple classes of antimicrobials. With no available vaccine, managing N. gonorrhoeae infections demands effective preventive measures, antibiotic treatment and epidemiological surveillance. The latter two are progressively being supported by the generation of whole-genome sequencing (WGS) data on behalf of national and international surveillance programmes. In this context, this study aims to perform N. gonorrhoeae clustering into genogroups based on WGS data, for enhanced prospective laboratory surveillance. Particularly, it aims to identify the major circulating WGS-genogroups in Europe and to establish a relationship between these and AMR. Ultimately, it enriches public databases by contributing with WGS data from Portuguese isolates spanning 15 years of surveillance. A total of 3791 carefully inspected N. gonorrhoeae genomes from isolates collected across Europe were analysed using a gene-by-gene approach (i.e. using cgMLST). Analysis of cluster composition and stability allowed the classification of isolates into a two-step hierarchical genogroup level determined by two allelic distance thresholds revealing cluster stability. Genogroup clustering in general agreed with available N. gonorrhoeae typing methods [i.e. MLST (multilocus sequence typing), NG-MAST (N. gonorrhoeae multi-antigen sequence typing) and PubMLST core-genome groups], highlighting the predominant genogroups circulating in Europe, and revealed that the vast majority of the genogroups present a dominant AMR profile. Additionally, a non-static gene-by-gene approach combined with a more discriminatory threshold for potential epidemiological linkage enabled us to match data with previous reports on outbreaks or transmission chains. In conclusion, this genogroup assignment allows a comprehensive analysis of N. gonorrhoeae genetic diversity and the identification of the WGS-based genogroups circulating in Europe, while facilitating the assessment (and continuous monitoring) of their frequency, geographical dispersion and potential association with specific AMR signatures. This strategy may benefit public-health actions through the prioritization of genogroups to be controlled, the identification of emerging resistance carriage, and the potential facilitation of data sharing and communication.

Background review for the '2020 European guideline for the diagnosis and treatment of gonorrhoea in adults'

Gonorrhoea is a major public health concern globally. Increasing incidence and sporadic ceftriaxone-resistant cases, including treatment failures, are growing concerns. The 2020 European gonorrhoea guideline provides up-to-date evidence-based guidance regarding the diagnosis and treatment of gonorrhoea. The updates and recommendations emphasize significantly increasing gonorrhoea incidence; broad indications for increased testing with validated and quality-assured nucleic acid amplification tests (NAATs) and culture; dual antimicrobial therapy including high-dose ceftriaxone and azithromycin (ceftriaxone 1 g plus azithromycin 2 g) OR ceftriaxone 1 g monotherapy (ONLY in well-controlled settings, see guideline for details) for uncomplicated gonorrhoea when the antimicrobial susceptibility is unknown; recommendation of test of cure (TOC) in all gonorrhoea cases to ensure eradication of infection and identify resistance; and enhanced surveillance of treatment failures when recommended treatment regimens have been used. Improvements in access to appropriate testing, test performance, diagnostics, antimicrobial susceptibility surveillance and treatment, and follow-up of gonorrhoea patients are essential in controlling gonorrhoea and to mitigate the emergence and/or spread of ceftriaxone resistance and multidrug-resistant and extensively drug-resistant gonorrhoea. This review provides the detailed background, evidence base and discussions, for the 2020 European guideline for the diagnosis and treatment of gonorrhoea in adults (Unemo M, et al. Int J STD AIDS. 2020).

Demographic and behavioural factors associated with antimicrobial susceptibility to azithromycin and ceftriaxone in Neisseria gonorrhoeae

Antimicrobial resistance of Neisseria gonorrhoeae (NG) is of global public health concern. The aim of this study was to explore demographic and behavioural factors associated with antimicrobial susceptibility of NG to ceftriaxone and azithromycin. Gonococcal isolates (n = 391) from clients attending the Auckland Sexual Health Service, New Zealand, from July 2014 - June 2015 (n = 206), and July 2017 - June 2018 (n = 185), were tested for susceptibility to ceftriaxone and azithromycin. Laboratory data were linked with behavioural and demographic data. Geometric mean azithromycin MICs increased across the two time periods (0.239 mg/L in 2014/15 to 0.347 mg/L in 2017/18, p < 0.001), and ceftriaxone MICs decreased (0.007 mg/L in 2014/15 to 0.005 mg/L in 2017/18, p < 0.001). Demographic and behavioural factors were not associated with differences in ceftriaxone MICs; however azithromycin MICs were higher in men who have sex with men (0.356 mg/L) compared with the heterosexual study population (0.192 mg/L, p < 0.001) and were lower in Pacific peoples (0.201 mg/L, p < 0.001) and Māori (0.244 mg/L, p = 0.05) compared with those of European ethnicity (0.321 mg/L). Our findings show that azithromycin MICs increased in our region between 2014 and 2018; associations were seen with sexual orientation and ethnicity.

2020 European guideline for the diagnosis and treatment of gonorrhoea in adults

Gonorrhoea is a major public health concern globally. Increasing incidence and sporadic ceftriaxone-resistant cases, including treatment failures, are growing concerns. The 2020 European gonorrhoea guideline provides up-to-date evidence-based guidance regarding the diagnosis and treatment of gonorrhoea. The updates and recommendations emphasize significantly increasing gonorrhoea incidence; broad indications for increased testing with validated and quality-assured nucleic acid amplification tests and culture; dual antimicrobial therapy including high-dose ceftriaxone and azithromycin (ceftriaxone 1 g plus azithromycin 2 g) OR ceftriaxone 1 g monotherapy (ONLY in well-controlled settings, see guideline for details) for uncomplicated gonorrhoea when the antimicrobial susceptibility is unknown; recommendation of test of cure (TOC) in all gonorrhoea cases to ensure eradication of infection and identify resistance; and enhanced surveillance of treatment failures when recommended treatment regimens have been used. Improvements in access to appropriate testing, test performance, diagnostics, antimicrobial susceptibility surveillance and treatment, and follow-up of gonorrhoea patients are essential in controlling gonorrhoea and to mitigate the emergence and/or spread of ceftriaxone resistance and multidrug-resistant and extensively drug-resistant gonorrhoea. For detailed background, evidence base and discussions, see the background review for the present 2020 European guideline for the diagnosis and treatment of gonorrhoea in adults (Unemo M, et al. Int J STD AIDS. 2020).

Antimicrobial susceptibility of Neisseria gonorrhoeae in Barcelona during a five-year period, 2013 to 2017

IntroductionIncreasing rates of antimicrobial resistance in Neisseria gonorrhoeae cause problems for treating gonorrhoea.AimThis observational study aimed to describe isolates from all patients found infected with N. gonorrhoeae, in Barcelona, Spain, between 2013 and 2017, and with available antimicrobial susceptibility data.MethodsMinimum inhibitory concentrations (MICs) of penicillin (PEN), cefixime (CFM), ceftriaxone (CRO), azithromycin (AZM), ciprofloxacin (CIP), spectinomycin (SPT), fosfomycin (FOF) and gentamicin (GEN) were determined by E-test. Susceptibility was assessed using clinical breakpoints from the European Committee on Antimicrobial Susceptibility Testing. Time trends for PEN, CFM, AZM and CIP were investigated using logistic regression.ResultsOf 1,979 patients with infection (2,036 isolates), 1,888 (95.4%) were men. Patient median age was 32 years. The proportions of isolates resistant to extended-spectrum cephalosporins were low, with 0.3% (5/1,982) resistant to CRO and 4.9% (98/1,985) to CFM. AZM resistance prevalence was 2.7% (52/1,981), including 16 isolates detected in 2016 and 2017, with high-level resistance. For CIP, 51.3% (1,018/1,986) of isolates were resistant, and for PEN, 20.1% (399/1,985). All isolates were susceptible to SPT. MIC50 and MIC90 values of GEN were 4 and 6 mg/L and of FOF 12 and 24 mg/L, respectively. Between 2013 and 2017, PEN and CFM resistance rates each decreased from 28.1% (92/327) to 12.2% (70/572) and from 8.3% (27/327) to 4.4% (25/572) (p ≤ 0.0073). In contrast, AZM resistance prevalence appeared to increase from 1.5% in 2014 (5/340) to 3.0% (17/572) in 2017. No trend was identified for CIP.ConclusionAntimicrobial susceptibility surveillance is important to timely detect new phenotypes and trends.

Molecular epidemiological typing of Neisseria gonorrhoeae isolates identifies a novel association between genogroup G10557 (G7072) and decreased susceptibility to cefixime, Germany, 2014 to 2017

BackgroundEmerging antimicrobial resistance (AMR) challenges gonorrhoea treatment and requires surveillance.AimThis observational study describes the genetic diversity of Neisseria gonorrhoeae isolates in Germany from 2014 to 2017 and identifies N. gonorrhoeae multi-antigen sequence typing (NG-MAST) genogroups associated with AMR or some patient demographics.Methods1,220 gonococcal isolates underwent AMR testing and NG-MAST. Associations between genogroups and AMR or sex/age of patients were statistically assessed.ResultsPatients' median age was 32 years (interquartile range: 25-44); 1,078 isolates (88.4%) originated from men. In total, 432 NG-MAST sequence types including 156 novel ones were identified, resulting in 17 major genogroups covering 59.1% (721/1,220) of all isolates. Genogroups G1407 and G10557 (G7072) were significantly associated with decreased susceptibility to cefixime (Kruskal-Wallis chi-squared: 549.3442, df: 16, p < 0.001). Their prevalences appeared to decline during the study period from 14.2% (15/106) to 6.2% (30/481) and from 6.6% (7/106) to 3.1% (15/481) respectively. Meanwhile, several cefixime susceptible genogroups' prevalence seemed to increase. Proportions of isolates from men differed among genogroups (Fisher's exact test, p < 0.001), being e.g. lower for G25 (G51) and G387, and higher for G5441 and G2992. Some genogroups differed relative to each other in affected patients' median age (Kruskal-Wallis chi-squared:  47.5358, df:  16, p < 0.001), with e.g. G25 (G51) and G387 more frequent among ≤ 30 year olds and G359 and G17420 among ≥ 40 year olds.ConclusionAMR monitoring with molecular typing is important. Dual therapy (ceftriaxone plus azithromycin) recommended in 2014 in Germany, or only the ceftriaxone dose of this therapy, might have contributed to cefixime-resistant genogroups decreasing.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Translating mouthwash use for gonorrhoea prevention into a public health campaign: identifying current knowledge and research gaps

The gonorrhoea rate among gay and bisexual men who have sex with men (MSM) has been increasing rapidly in many Western countries. Furthermore, gonorrhoea is becoming increasingly resistant to antibiotics and only limited options remain for treatment. Recent evidence suggests that the oropharynx may play an important role in gonorrhoea transmission. It is hypothesised that reducing the prevalence of oropharyngeal gonorrhoea will also reduce the population incidence of gonorrhoea. Mouthwash has been proposed as a novel non-antibiotic intervention to prevent oropharyngeal gonorrhoea; hence, reducing the probability of antibiotic resistance developing. However, its efficacy is yet to be confirmed by a randomised controlled trial - the findings of which will be available in 2019. If the trial shows mouthwash is effective in preventing gonorrhoea, this finding could potentially be translated into a public health campaign to increase the mouthwash use in the MSM population. This article summarises the current evidence of the effectiveness of mouthwash against gonorrhoea and discusses the potential literature gaps before implementing the mouthwash intervention at a population level.

Optimising treatments for sexually transmitted infections: surveillance, pharmacokinetics and pharmacodynamics, therapeutic strategies, and molecular resistance prediction

Progressive antimicrobial resistance in Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis has created a pressing need for treatment optimisations for sexually transmitted infections (STIs). In this Review, we aim to highlight urgent needs in global STI management, including: (1) improved surveillance to monitor antimicrobial resistance and clinical outcomes; (2) systematic pharmacokinetic and pharmacodynamic evaluations to ensure resistance suppression and bacterial eradication at all sites of infection; (3) development of novel, affordable antimicrobials; and (4) advancements in new molecular and point-of-care tests to detect antimicrobial resistance determinants. Antimicrobial resistance among STIs is a global public health crisis. Continuous efforts to develop novel antimicrobials will be essential, in addition to other public health interventions to reduce the global STI burden. Apart from prevention through safer sexual practices, the development of STI vaccines to prevent transmission is a crucial research priority.

Prevalence of mutations associated with resistance to macrolides and fluoroquinolones in Mycoplasma genitalium: a systematic review and meta-analysis

BACKGROUND

Mycoplasma genitalium is now recognised as an important bacterial sexually transmitted infection. We summarised data from studies of mutations associated with macrolide and fluoroquinolone resistance in M genitalium to establish the prevalence of resistance. We also investigated temporal trends in resistance and aimed to establish the association between resistance and geographical location.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, and MEDLINE for studies that included data for the prevalence of mutations associated with macrolide and fluoroquinolone resistance in M genitalium published in any language up to Jan 7, 2019. We defined prevalence as the proportion of M genitalium samples positive for key mutations associated with azithromycin resistance (23S rRNA gene, position 2058 or 2059) or moxifloxacin resistance (S83R, S83I, D87N, or D87Y in parC), or both, among all M genitalium samples that were successfully characterised. We used random-effects meta-analyses to calculate summary estimates of prevalence. Subgroup and meta-regression analyses by WHO region and time period were done. This study was registered with PROSPERO, number CRD42016050370.

RESULTS

Overall, 59 studies from 21 countries met the inclusion criteria for our study: 57 studies of macrolide resistance (8966 samples), 25 of fluoroquinolone resistance (4003 samples), and 22 of dual resistance to macrolides and fluoroquinolones (3280 samples). The summary prevalence of mutations associated with macrolide resistance among M genitalium samples was 35·5% (95% CI 28·8-42·5); prevalence increased from 10·0% (95% CI 2·6-20·1%) before 2010, to 51·4% (40·3-62·4%) in 2016-17 (p<0·0001). Prevalence of mutations associated with macrolide resistance was significantly greater in samples in the WHO Western Pacific and Americas regions than in those from the WHO European region. The overall prevalence of mutations associated with fluoroquinolone resistance in M genitalium samples was 7·7% (95% CI 4·5-11·4%). Prevalence did not change significantly over time, but was significantly higher in the Western Pacific region than in the European region. Overall, the prevalence of both mutations associated with macrolide resistance and those associated with fluoroquinolone resistance among M genitalium samples was 2·8% (1·3-4·7%). The prevalence of dual resistance did not change significantly over time, and did not vary significantly by geographical region.

INTERPRETATION

Global surveillance and measures to optimise the efficacy of treatments-including resistance-guided strategies, new antimicrobials, and antimicrobial combination approaches-are urgently needed to ensure cure in a high proportion of M genitalium infections and to prevent further spread of resistant strains.

FUNDING

Australian National Health and Medical Research Council.

Determining antimicrobial resistance profiles and identifying novel mutations of Neisseria gonorrhoeae genomes obtained by multiplexed MinION sequencing

Gonorrhea is one of the most common sexually transmitted diseases worldwide. To cure infection and prevent transmission, timely and appropriate antimicrobial therapy is necessary. Unfortunately, Neisseria gonorrhoeae, the etiological agent of gonorrhea, has acquired nearly all known mechanisms of antimicrobial resistance (AMR), thereby compromising the efficacy of antimicrobial therapy. Treatment failure resulting from AMR has become a global public health concern. Whole-genome sequencing is an effective method to determine the AMR characteristics of N. gonorrhoeae. Compared with next-generation sequencing, the MinION sequencer (Oxford Nanopore Technologies (ONT)) has the advantages of long read length and portability. Based on a pilot study using MinION to sequence the genome of N. gonorrhoeae, we optimized the workflow of sequencing and data analysis in the current study. Here we sequenced nine isolates within one flow cell using a multiplexed sequencing strategy. After hybrid assembly with Illumina reads, nine integral circular chromosomes were obtained. By using the online tool Pathogenwatch and a BLAST-based workflow, we acquired complete AMR profiles related to seven classes of antibiotics. We also evaluated the performance of ONT-only assemblies. Most AMR determinants identified by ONT-only assemblies were the same as those identified by hybrid assemblies. Moreover, one of the nine assemblies indicated a potentially novel antimicrobial-related mutation located in mtrR which results in a frame-shift, premature stop codon, and truncated peptide. In addition, this is the first study using the MinION sequencer to obtain complete genome sequences of N. gonorrhoeae strains which are epidemic in China. This study shows that complete genome sequences and antimicrobial characteristics of N. gonorrhoeae can be obtained using the MinION sequencer in a simple and cost-effective manner, with hardly any knowledge of bioinformatics required. More importantly, this strategy provides us with a potential approach to discover new AMR determinants.

Point-by-Point Progress: Gonorrhea Point of Care Tests

INTRODUCTION

Point-of-care (POC) tests for Neisseria gonorrhoeae (Ng) are urgently needed to control the gonorrhea epidemic, so patients can receive immediate diagnoses and treatment. While the advent of nucleic acid amplification tests (NAATs) has improved the accuracy of Ng identification, very few POC assays are able to provide results of such tests at the clinical visit. Additionally, antimicrobial resistance (AMR) presents a unique treatment challenge for Ng.

AREAS COVERED

This review notes that older POC tests have lower sensitivity for Ng, compared to the currently-available NAATs, and are not adequate for the current demand for high sensitivity. Promising newer assays, which can be used at the POC are covered. This review also includes data about clinicians' and patients' acceptability and expectations of POC tests for Ng, testing of extragenital specimens, pooling studies, as well as their impact clinically, and use in low-resource settings.

EXPERT OPINION

The ability to use POC tests to identify and immediately treat Ng infections at the patient encounter offers many benefits and opportunities. POC tests for Ng are currently available, but not widely used especially in low-resource settings. Further development of POC tests with AMR testing capacity is needed to help guide antimicrobial stewardship.

Fifteen years of a nationwide culture collection of Neisseria gonorrhoeae antimicrobial resistance in Portugal

Neisseria gonorrhoeae antimicrobial resistance (AMR) and gonorrhea disease burden remain major public health concerns worldwide. To contribute to the supranational demands to monitor and manage the spread of antimicrobial-resistant N. gonorrhoeae, the Portuguese NIH promoted the creation of the National Laboratory Network for Neisseria gonorrhoeae Collection (PTGonoNet). The present study reports the N. gonorrhoeae major AMR trends observed from 2003 up to 2018. All isolates described in the present study constitute the opportunistic ongoing N. gonorrhoeae isolate collection supported by the National Reference Laboratory for Sexually Transmitted Infections of the Portuguese NIH, enrolling strains isolated in 35 different public and private laboratories. Minimum inhibitory concentrations were determined using E-tests for azithromycin, benzylpenicillin, cefixime, ceftriaxone, ciprofloxacin, gentamicin, spectinomycin and tetracycline. Molecular typing was determined using NG-MAST. AMR data of 2596 country-spread isolates show that 87.67% of all N. gonorrhoeae isolates presented decreased susceptibility to at least one antimicrobial. A continuous decreased susceptibility and resistance to penicillin, tetracycline and ciprofloxacin can be observed along the years. However, no decreased susceptibility to cephalosporins was observed until 2018, while for azithromycin, this was always low. The most common observed NG-MAST genogroups were G1407, G7445, G225, G2, and G1034. This study evidences the advantages of a nationwide collection of isolates and of centralized AMR testing to respond to supranational (EURO-GASP) requirements while providing unprecedented data on AMR in the context of 15 years of surveillance.

Sharp increase in ciprofloxacin resistance of Neisseria gonorrhoeae in Yaounde, Cameroon: analyses of a laboratory database period 2012-2018

A previous study conducted in Yaoundé, Cameroon, showed a significant increase in ciprofloxacin-resistant Neisseria gonorrhoeae. Still, ciprofloxacin is the recommended first-line medication for gonorrhoea in Cameroon. We aimed to provide further evidence of increasing resistance of N. gonorrhoeae to ciprofloxacin. We conducted a retrospective study (2012–2018) and retrieved coded patient and specimen real-world data from the Centre Pasteur du Cameroun’s laboratory information system and laboratory worksheets. We included disc diffusion method results for tetracycline, azithromycin, and spectinomycin, and minimal inhibitory concentrations obtained by E-test for ciprofloxacin, ceftriaxone, and benzylpenicillin. A total of 449 N. gonorrhoeae were isolated; a higher proportion of them presented resistance to ciprofloxacin (64.4%), benzylpenicillin (80.1%), and tetracycline (58.4%). The resistance to ciprofloxacin increased significantly (p < 0.0001) from 15.0% in 2012 to 79.5% in 2018. Since 2016 a significant decrease (p = 0.002) in resistance to benzylpenicillin occurred and the resistance to tetracycline remained stable. The level of resistance to ceftriaxone (1.8%), azithromycin (2.1%), and spectinomycin (2.0%) was low. Our study confirms that ciprofloxacin is not recommended as a first-line treatment for gonorrhoea. It also illustrates the urgent need to establish a robust and sustainable gonococcal antimicrobial surveillance programme to guide national treatment guidelines in order to control gonorrhoea in Cameroon.

[Classical sexually transmitted diseases in the anorectal region]

BACKGROUND

Sexually transmitted infections (STIs) in the anorectal region are disproportionally detected in risk populations such as men who have sex with men (MSM). However, due to changes in sexual behaviour they are increasingly diagnosed in heterosexual individuals. Due to the recent implementation of oral HIV pre-exposure prophylaxis together with lack of condom use, a further rise in STIs is expected.

OBJECTIVES

This review addresses epidemiology, clinical picture, diagnostic pitfalls and current therapy guidelines of "classical" bacterial STIs involving the anorectum.

CONCLUSIONS

STI manifestations in the anal region are frequently nonspecific or asymptomatic so that the diagnosis may be missed. In an endoscopic examination of the rectum, they can even mimic inflammatory bowel disease or malignancy. Therefore, knowledge of possible symptoms of bacterial STIs in this area is helpful for early diagnosis. Coinfections with other STIs are common and should prompt a search of other pathogens including HIV and hepatitis B/C.

Genomic epidemiology and population structure of Neisseria gonorrhoeae in Norway, 2016-2017

This study presents the nationwide epidemiology of Neisseria gonorrhoeae, using whole-genome sequencing of all culture-positive cases, which comprise roughly 40 % of all cases of gonorrhea reported in Norway from 2016 to 2017. Isolates were assigned to sequence types and Bayesian analysis clusters and variation in genes coding for antibiotic resistance was linked to phenotypic resistance data. The study also included isolates taken from the same patients from different anatomical sites at one or more time points. Comparing these isolates allows for observation of patterns of infections, i.e. multiple reinfections of genetically related clones vs. reinfections of genetically distant clones, and quantification of the genomic variation of closely related isolates from samples taken from a patient within the same day. Demographically, the patients in the study could be split into two groups; one group of patients from the capital with a high proportion of men who have sex with men (MSM), and another consisting of young adults with transmission primarily between males and females from outside the capital. Some clusters of N. gonorrhoeae were restricted to one of these two demographic groups. Pairwise comparison of multiple isolates from the same patients revealed that most were reinfected with different clones. Observations of frequent reinfections in patients is a concern and should be taken into account in the development of improved information and treatment guidelines.

Genomic evolution of Neisseria gonorrhoeae since the preantibiotic era (1928-2013): antimicrobial use/misuse selects for resistance and drives evolution

BACKGROUND

Multidrug-resistant Neisseria gonorrhoeae strains are prevalent, threatening gonorrhoea treatment globally, and understanding of emergence, evolution, and spread of antimicrobial resistance (AMR) in gonococci remains limited. We describe the genomic evolution of gonococci and their AMR, related to the introduction of antimicrobial therapies, examining isolates from 1928 (preantibiotic era) to 2013 in Denmark. This is, to our knowledge, the oldest gonococcal collection globally.

METHODS

Lyophilised isolates were revived and examined using Etest (18 antimicrobials) and whole-genome sequencing (WGS). Quality-assured genome sequences were obtained for 191 viable and 40 non-viable isolates and analysed with multiple phylogenomic approaches.

RESULTS

Gonococcal AMR, including an accumulation of multiple AMR determinants, started to emerge particularly in the 1950s-1970s. By the twenty-first century, resistance to most antimicrobials was common. Despite that some AMR determinants affect many physiological functions and fitness, AMR determinants were mainly selected by the use/misuse of gonorrhoea therapeutic antimicrobials. Most AMR developed in strains belonging to one multidrug-resistant (MDR) clade with close to three times higher genomic mutation rate. Modern N. gonorrhoeae was inferred to have emerged in the late-1500s and its genome became increasingly conserved over time.

CONCLUSIONS

WGS of gonococci from 1928 to 2013 showed that no AMR determinants, except penB, were in detectable frequency before the introduction of gonorrhoea therapeutic antimicrobials. The modern gonococcus is substantially younger than previously hypothesized and has been evolving into a more clonal species, driven by the use/misuse of antimicrobials. The MDR gonococcal clade should be further investigated for early detection of strains with predispositions to develop and maintain MDR and for initiation of public health interventions.

Antimicrobial resistance in sexually transmitted infections

RATIONALE FOR REVIEW

International travel facilitates the spread of drug-resistant infections, including sexually transmitted infections (STIs). In 2016, the World Health Organization highlighted the global burden of 'curable' STIs, estimating 376 million new infections of gonorrhoea, chlamydia, syphilis and trichomoniasis annually, with considerable geographic variation in both the burden of disease and prevalence of resistance. Travelers' risk of contracting and transmitting drug-resistant STIs depends in part on their geographic exposure. In this review, we describe the epidemiology of antimicrobial resistance (AMR) and the management of these four common STIs and Mycoplasma genitalium, an increasingly recognized cause of non-gonococcal urethritis.

KEY FINDINGS

Multi-drug and extensively drug resistant gonorrhoea strains have been associated with international spread, particularly in travelers returning from Southeast Asia. Chlamydia is the most common bacterial STI worldwide. Although in vitro resistance has been reported, surveillance data suggest that clinically significant resistance to macrolides and tetracyclines is rare. Macrolide resistance in syphilis is now endemic in much of the world but there is no documented penicillin resistance, which remains first-line therapy. Trichomoniasis is the most common non-viral STI worldwide. Although clinical failure after treatment occurs, resistance to metronidazole is thought to be uncommon. Mycoplasma genitalium exhibits intrinsic resistance to many antibiotics, and the prevalence of resistance to both first- and second-line regimens (macrolides and fluoroquinolones) is increasing worldwide, with limited alternative therapeutic options.

RECOMMENDATIONS

International travelers are at risk for acquiring resistant STIs with limited therapeutic options. Improved diagnostics are urgently needed to improve AMR surveillance and the management of infected patients. As no vaccinations are currently available for these STIs, and pre-exposure prophylaxis is an area of active study with limited data, condom use is critical for prevention. Travel medicine providers should incorporate STI risk reduction counselling, with an emphasis on condom use, into the routine pre-travel consultation.

Susceptibility of invasive Neisseria meningitidis strains isolated in Germany to azithromycin, an alternative agent for post-exposure prophylaxis

Background

Post-exposure prophylaxis (PEP) for close contacts of invasive meningococcal disease (IMD) cases is recommended in most countries to avoid secondary cases by eradicating supposed meningococcal colonization. Currently, rifampicin, ciprofloxacin and ceftriaxone are recommended in many countries including Germany. Azithromycin has been shown to eradicate meningococcal colonization.

Objectives

To assess the azithromycin susceptibility of invasive Neisseria meningitidis isolates.

Methods

A subset of German invasive meningococcal isolates from 2006–18 was selected for this study. Azithromycin MIC was determined using broth microdilution and agar gradient diffusion.

Results

Azithromycin MICs as determined by broth microdilution ranged from &lt;0.003 to 2 mg/L (median 0.50 mg/L, Q75 1 mg/L). All isolates were susceptible to azithromycin according to the CLSI breakpoint (95% CI 0.0%–1.5%). There was no significant correlation between MICs determined by broth microdilution and agar gradient diffusion. Nevertheless, the two methods were consistent regarding the categorization of all isolates as susceptible.

Conclusions

Azithromycin is an eligible antibiotic for PEP of IMD close contacts. It is approved for adults as well as children and may even be used in pregnancy. Because of easier application and lower toxicity, it might be an alternative to rifampicin and ciprofloxacin, as we found no resistant isolates. Since a gonococcal gene associated with elevated azithromycin MICs has been reported in N. meningitidis, careful monitoring of the emergence of resistant strains is nevertheless necessary for meningococci. Lack of concordance of MICs between broth microdilution and agar gradient diffusion needs to be considered.

A review of current guidelines and research on the management of sexually transmitted infections in adolescents and young adults

Adolescents and young adults are at high risk for sexually transmitted infections (STIs). Providers have the responsibility to accurately manage these infections to prevent medical complications and the spread of STIs. This article will review the epidemiology, screening recommendations, diagnostic tests, and treatment guidelines for STIs most commonly encountered in this population: Chlamydia trachomatis, Neisseria gonorrhoeae, Herpes simplex virus, and Trichomonas vaginalis, as well as the sexually associated infection bacterial vaginosis. This review will discuss ongoing research that explores ways to improve the management of STIs in adolescents and young adults.