Susceptibility of Neisseria gonorrhoeae to azithromycin and ceftriaxone in China: A retrospective study of national surveillance data from 2013 to 2016

Etiological, sociodemographic and clinical characteristics of sexually transmitted infections and M. genitalium resistance in Shenzhen: a multicenter cross-sectional study in China

Introduction

This study aims to determine the etiological, sociodemographic, and clinical characteristics of STIs, and the level of resistance in M. genitalium in Shenzhen, a representative first-tier city of southern China.

Methods

A multicenter cross-sectional study was conducted and 7886 sexually active participants attending STI-related departments were involved from 22 hospitals. Nine STI-related organisms including N. gonorrhoeae, C. trachomatis, T. vaginalis, M. genitalium, HSV-1, HSV-2, M. hominis, U. parvum, and U. urealyticum were screened.

Results

Being single or divorced was associated with increased detection of N. gonorrhoeae, C. trachomatis, M. genitalium, HSV-1, HSV-2 and M. hominis. Lower education level was associated with increased detection of C. trachomatis, HSV-2 and M. hominis. No insurance coverage was an independent risk factor for T. vaginalis, M. hominis and U. parvum positivity. Three resistance-determining regions related to macrolide and fluoroquinolone were sequenced in 154 M. genitalium positive samples, among which 90.3% harbored mutations related to macrolide or fluroquinolone resistance and 67.5% were multidrug-resistant M. genitalium. A2072G in 23S rRNA and Ser83Ile in parC were the most common mutations. M. hominis was associated with manifestations of bacterial vaginosis in female and epididymitis in male.

Conclusions

Single or divorced individuals, those with lower education level and individuals without insurance are higher-risk key populations for STIs. The prevalence of antimicrobial-resistant M. genitalium in Shenzhen is high. Detection of M. hominis increased significantly with lower education level and no health insurance coverage, and it is associated with bacterial vaginosis or epididymitis, indicating that M. hominis deserves further attention.

A systematic review and meta-analysis of sexually transmitted infections and blood-borne viruses in travellers

BACKGROUND

Sexually transmitted infections (STIs) and blood-borne viruses (BBVs) impose a global health and economic burden. International travellers facilitate the spread of infectious diseases, including STIs. Hence, this review assessed the prevalence/proportionate morbidity of travellers with STIs and sexually transmitted BBVs and factors associated with the infection in this population.

METHODS

PubMed, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase and Cochrane Library were searched from inception of the databases until November 2022. Published analytical observational studies reporting the prevalence/proportionate morbidity of travellers with STIs and factors associated with STIs by type of traveller [i.e. tourists, business travellers, students, visiting friends or relatives (VFRs), international truck drivers, backpackers, expatriates and men who have sex with men (MSM)] were included. The selection of articles, data extraction and risk of bias assessment were conducted by two independent reviewers. Meta-analyses were conducted for each STI by clinical presentation and type of traveller.

RESULTS

Thirty-two studies (n = 387 731 travellers) were included; 19 evaluated the proportionate morbidity of STIs among symptomatic travellers, while 13 examined the prevalence of STIs in asymptomatic travellers. The highest proportionate morbidity was found among VFRs (syphilis, 1.67%; 95% CI: 1.03-2.81%), backpackers (Chlamydia trachomatis, 6.58%; 95% CI: 5.96-7.25%) and MSM (HIV [2.50%;95% CI: 0.44-12.88%], gonorrhoea [4.17%; 95% CI: 1.1.5-13.98%], lymphogranuloma venereum [4.17%;95% CI: 1.1.5-13.98%] and HAV [20.0%; 95% CI: 14.99-26.17%]). The highest prevalence of STIs among asymptomatic were found in MSM (HIV [25.94%; 95% CI: 22.21-30.05%] and HBV [24.90%; 95% CI: 21.23-28.96%]) and backpackers (C. trachomatis, 3.92%; 95% CI: 2.72-5.32%). Short duration of the trip (<1 month), not having pre-travel consultation, travelling to Southeast Asia and being unvaccinated for HBV were identified as risk factors for STIs.

CONCLUSION

Strategies to prevent STIs and sexually transmitted BBVs should be discussed at pre-travel consultations, and recommendations should be prioritized in high-risk groups of travellers, such as backpackers, VFRs and MSMs. Additionally, healthcare providers should tailor recommendations for safe sex practices to individual travellers' unique needs.

Analytical and clinical validation of a multiplex PCR assay for detection of Neisseria gonorrhoeae and Chlamydia trachomatis including simultaneous LGV serotyping on an automated high-throughput PCR system

For effective infection control measures for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), a reliable tool for screening and diagnosis is essential. Here, we aimed to establish and validate a multiplex PCR assay on an automated system using a dual-target approach for the detection of CT/NG and differentiation between lymphogranuloma venereum (LGV) and non-LGV from genital and extra-genital specimens. Published primer/probe sets (CT: pmpH, cryptic plasmid; NG: porA, opa) were modified for the cobas 5800/6800/8800. Standards quantified by digital PCR were used to determine linearity and lower limit of detection (LLoD; eSwab, urine). For clinical validation, prospective samples (n = 319) were compared with a CE-marked in vitro diagnostics (CE-IVD) assay. LLoDs ranged from 21.8 to 244 digital copies (dcp)/mL and 10.8 to 277 dcp/mL in swab and urine, respectively. A simple linear regression analysis yielded slopes ranging from -4.338 to -2.834 and Pearson correlation coefficients from 0.956 to 0.994. Inter- and intra-run variability was <0.5 and <1 cycle threshold (ct), respectively. No cross-reactivity was observed (n = 42). Clinical validation showed a sensitivity of 94.74% (95% confidence interval (CI): 87.23%-97.93%) and 95.51% (95% CI: 89.01%-98.24%), a specificity of 99.59% (95% CI: 97.71%-99.98%) and 99.57% (95% CI: 97.58%-99.98%), positive predictive values of 89.91% (estimated prevalence: 3.7%; 95% CI: 80.91%-95.6%) and 88.61% (estimated prevalence: 3.4%; 95% CI: 80.18%-94.34%), and negative predictive values of 99.81% (95% CI: 98.14%-100%) and 99.85% (95% CI: 98.14%-100%) for the detection of CT and NG, respectively. In conclusion, we established a dual-target, internally controlled PCR on an automated system for the detectiwon of CT/NG from genital and extra-genital specimens. Depending on local regulations, the assay can be used as a screening or a confirmatory/typing assay.IMPORTANCEChlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) represent a major global health burden, with the World Health Organization estimating that >128 million and >82 million people, respectively, were newly infected in 2020. For effective infection control measures, a reliable tool for sensitive diagnosis and screening of CT/NG is essential. We established a multiplex PCR assay for the detection of CT/NG and simultaneous discrimination between lymphogranuloma venereum (LGV) and non-LGV strains, which has been validated for genital and extra-genital specimens on a fully automated system. To increase assay sensitivity, a dual-target approach has been chosen for both pathogens. This strategy reduces false-positive results in oropharyngeal swabs due to the detection of commensal N. species that may harbor NG DNA fragments targeted in the PCR due to horizontal gene transmission following previous infection. In sum, the established assay provides a powerful tool for use as either a screening/diagnostic or a typing/confirmatory assay.

Rhynchophorus ferrugineus larvae: A novel source for combating broad-spectrum bacterial and fungal infections

Antimicrobial resistance is a growing concern due to the growth of antibiotic-resistant microorganisms, which makes it difficult to treat infection. Due to its broad-spectrum antimicrobial properties against a diverse array of bacteria, both Gram-positive and Gram-negative bacteria, and fungi, Rhynchophorus ferrugineus larval antimicrobial peptides (AMPs) have demonstrated potential as antimicrobial agents for the treatment of microbial infections and prevention of antibiotic resistance. This study emphasizes the unexplored mechanisms of action of R. ferrugineus larvae against microorganisms. Among the most widely discussed mechanisms is the effect of AMPs in larvae in response to a threat or infection. Modulation of immune-related genes in the intestine and phagocytic capacity of its hemocytes may also affect the antimicrobial activity of R. ferrugineus larvae, with an increase in phenoloxidase activity possibly correlated with microbial clearance and survival rates of larvae. The safety and toxicity of R. ferrugineus larvae extracts, as well as their long-term efficacy, are also addressed in this paper. The implications of future research are explored in this paper, and it is certain that R. ferrugineus larvae have the potential to be developed as a broad-spectrum antimicrobial agent with proper investigation.

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.

Genomic epidemiology of Neisseria gonorrhoeae in Shenzhen, China, during 2019-2020: increased spread of ceftriaxone-resistant isolates brings insights for strengthening public health responses

The antimicrobial resistance (AMR) in gonorrhea poses global threat of increasing public health concern. In response to this concern, molecular surveillance has been widely utilized to detail the changes in the evolution and distribution of Neisseria gonorrhoeae during AMR transmission. In this study, we performed a comprehensive molecular surveillance of 664 N. gonorrhoeae isolates collected in Shenzhen, one of the cities with the largest mobile population in China, 2019-2020. In 2020, ceftriaxone showed an unprecedented high resistance rate of 24.87%, and 67.83% of the ceftriaxone-resistant (Cro-R) isolates harbored a nonmosaic penA allele. The Cro-R isolates with nonmosaic penA alleles showed a tremendous increasing trend from 0.00% in 2014 to 20.45% in 2020, which proves the need for monitoring nonmosaic penA-related resistance. Importantly, genotyping indicated that multilocus sequence typing ST11231 (35.71%) had a notable rate of ceftriaxone resistance, which might become the focus of future surveillance. Whole-genome sequencing analysis showed that the internationally spreading FC428 clones have circulated in Shenzhen region with typical ceftriaxone resistance (MIC ≥ 0.5 mg/L) maintained. Our surveillance combined with genomic analysis provides current information to update gonorrhea management guidelines and emphasizes that continuous AMR surveillance for N. gonorrhoeae is essential. IMPORTANCE We conducted a comprehensive molecular epidemiology analysis for antimicrobial-resistant Neisseria gonorrhoeae in Shenzhen during 2019-2020, which provided important data for personalized treatment and adjustment of monitoring strategy. Briefly, the proportion of ceftriaxone-resistant (Cro-R) isolates reached a stunning prevalence rate of 24.87% in 2020. A typical increment of Cro-R isolates with nonmosaic penA alleles proves the necessity of monitoring nonmosaic AMR mechanism and involving it into developing molecular detection methods. Whole-genome sequencing analysis showed that the international spreading FC428 clone has been circulating in Shenzhen with typical ceftriaxone resistance (MIC ≥ 0.5 mg/L) maintained. In summary, we conducted a comprehensive epidemiology study, providing significant data for therapy management. Our results not only improve the understanding of the distribution and transmission of AMR in N. gonorrhoeae but also provide effective AMR data for improving surveillance strategies in China.

Antimicrobial Resistance Profiling and Genome Analysis of the penA-60.001 Neisseria gonorrhoeae Clinical Isolates in China in 2021

BACKGROUND

Neisseria gonorrhoeae antimicrobial resistance (AMR) is an urgent public health threat. With dissemination of FC428-related clones, the efficacy of ceftriaxone has become controversial.

METHODS

Agar dilution and whole genome sequencing were used to analyze AMR.

RESULTS

High resistance to penicillin (75.2%), tetracycline (87.9%), ciprofloxacin (98.3%), ceftriaxone (8.9%), cefixime (14.3%), and azithromycin (8.6%) was observed among 463 isolates first collected in China in 2021. All penA-60.001 clones exhibited resistance to ceftriaxone or cefixime, and 1 of the 12 cases was resistant to azithromycin. ngMAST and ngSTAR of penA-60.001 isolates showed that single-nucleotide polymorphisms in the porB, tbpB, ponA, gyrA, and parC genes were the major causes of different sequence types. MLST-7365 (n = 5) and MLST-1903 (n = 3) were main genotypes, and the other 4 strains featured MLST-10314, MLST-13871, MLST-7827 and MLST-1600. Furthermore, resistance markers (eg, penA, blaTEM-1, blaTEM-135) and virus factors were detected. Most penA-60.001 strains were fully mixed with global FC428-related clones; 2021-A2 and F89 had the same origin; and 2021-A1 exhibited a unique evolutionary trajectory.

CONCLUSIONS

Results provide the first demonstration of extremely severe AMR rates of N gonorrhoeae in China in 2021, particularly strains with ceftriaxone decreased susceptibility. The sustained transmission of penA-60.001 subclones might further threaten treatment effectiveness.

Identification of ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone and isolates harboring a novel mosaic penA gene in Chengdu in 2019-2020

BACKGROUND

Antimicrobial resistance in gonorrhea has become a growing global public health burden. Neisseria gonorrhoeae isolates with resistance to ceftriaxone, the last remaining first-line option, represent an emerging threat of untreatable gonorrhea.

METHODS

A total of ten ceftriaxone-resistant N. gonorrhoeae FC428 isolates and two isolates harboring a novel mosaic penA-232.001 allele from 160 gonococcal isolates in Chengdu in 2019-2020 was described in the present study. Multilocus sequence typing (MLST) and N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were performed to characterize the isolates. Whole genome sequencing and maximum-likelihood method were performed to infer how the genetic phylogenetic tree of these isolates looks like. Recombination analysis was performed using the RDP4 software. This study was registered in the Chinese Clinical Trial Registry (ChiCTR2100048771, registration date: 20210716).

RESULTS

The genetic phylogeny showed that the ten FC428 isolates sporadically clustered into different phylogenetic clades, suggesting different introductions and local transmission of FC428. Two isolates showed close genetic relatedness to ceftriaxone-resistant clone A8806, which was only reported from Australia in 2013. Homologous recombination events were detected in penA between Neisseria gonorrhoeae and commensal Neisseria species (N. perflava and N. polysaccharea), providing evidence of commensal Neisseria species might serve as reservoirs of ceftriaxone resistance-mediating penA sequences in clinical gonococcal strains.

CONCLUSIONS

Our results demonstrate further dissemination of FC428 in China and resurgence risks of sporadic ceftriaxone-resistant A8806 to become the next clone to spread.

Pay-it-forward gonorrhea and chlamydia testing among men who have sex with men and male STD patients in China: the PIONEER pragmatic, cluster randomized controlled trial protocol

BACKGROUND

Gonorrhea and chlamydia are the most common sexually transmitted diseases (STDs) among men who have sex with men (MSM) in China. Previous studies have shown pay-it-forward (PIF) interventions to be associated with a substantial increase in gonorrhea and chlamydia test uptake compared to standard-of-care. We propose a 'pay-it-forward' gonorrhea and chlamydia testing randomized controlled trial (PIONEER). The trial would evaluate the effectiveness of two pay-it-forward strategies in promoting testing uptake compared to the standard of care (in which men pay for their tests out-of-pocket) among MSM and male STD patients in China.

METHODS

PIONEER will be a three-armed, pragmatic cluster randomized controlled trial (RCT), conducted across 12 clinics (six MSM-led and six public STD clinics) to compare the effectiveness of three implementation strategies. Each facility will be randomized to a standard pay-it-forward intervention of gonorrhea/ chlamydia testing with minimal encouragement for testing, a community-engaged pay-it-forward arm, or a control arm where men pay for their tests out-of-pockets. The primary outcome will be dual gonorrhea/chlamydia test uptake. Secondary outcomes will include syphilis testing, amount donated in pay-it-forward, number of positive gonorrhea and chlamydia tests, and measures of antimicrobial resistance. A sequential transformative mixed methods design will be used to evaluate the implementation process in type 2 effectiveness-implementation hybrid design. Data sources will include survey on acceptability, and feelings and attitudes towards the interventions among participants; testing and treatment uptake data from clinic records, WeChat records, and qualitative data to gain insights into men's perceptions and attitudes towards the pay-it-forward, mechanisms driving uptake, and donating behaviors. Implementers and organizers will be interviewed about fidelity and adherence to protocol, sustainability of pay-it-forward intervention, and barriers and facilitators of implementing the intervention.

DISCUSSION

PIONEER will substantially increase gonorrhea/chlamydia testing among MSM in China, providing an innovative and new financial mechanism to sustain STD screening among sexual minorities in low- and middle-income countries. This study will answer compelling scientific questions about how best to implement pay-it-forward and the individual and organizational characteristics that moderate it.

TRIAL REGISTRATION

The study with identification number NCT05723263 has been registered on clinicaltrials.gov/.

Point-of-care detection of Neisseria gonorrhoeae based on RPA-CRISPR/Cas12a

Gonorrhea, caused by Neisseria gonorrhoeae (N. gonorrhoeae), is a persistent global public health threat. The development of low-cost, point-of-care testing is crucial for gonorrhea control, especially in regions with limited medical facilities. In this study, we integrated CRISPR/Cas12a reaction with recombinase polymerase amplification (RPA) to provide a simple and adaptable molecular detection method for N. gonorrhoeae. The RPA-Cas12a-based detection system developed in this study enables rapid detection of N. gonorrhoeae within 1 h without the use of specialized equipment. This method is highly specific for identifying N. gonorrhoeae without cross-reactivity with other prevalent pathogens. Furthermore, in the evaluation of 24 clinical samples, the detection system demonstrates a 100% concordance rate with traditional culture, which is being used clinically as a reference method. Overall, the RPA-Cas12a-based N. gonorrhoeae detection has the advantages of rapidity, portability, low-cost, no special equipment required, and strong operability, and has a high potential for application as a self-testing and point-of-care diagnosis, which is critical for the clinical management of gonorrhea in developing countries lacking medical equipment.

Dissemination of Neisseria gonorrhoeae with decreased susceptibility to extended-spectrum cephalosporins in Southern China, 2021: a genome-wide surveillance from 20 cities

BACKGROUND

Antimicrobial resistance (AMR) of untreatable gonococcal infection is an emerging threat, especially in Guangdong, a prosperous province in Southern China.

METHODS

N.gonorrhoeae was isolated from 20 cities in Guangdong and determined antimicrobial susceptibility. Through whole-genome sequencing (WGS), multilocus sequence typing (MLST), N.gonorrhoeae multiantigen sequence typing (NG-MAST), and N.gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were obtained based on the PubMLST database ( https://pubmlst.org/ ). Phylogenetic analysis was used for dissemination and tracking analysis.

RESULTS

Antimicrobial susceptibility was performed on 347 isolates, and 50 isolates were identified as decreased susceptibility (DS) to cephalosporins. Of which 16.0% (8/50) were ceftriaxone DS, 38.0% (19/50) were cefixime DS, and 46.0% (23/50) were both ceftriaxone and cefixime DS. In all, the dual-resistant rate of the cephalosporin-DS isolates was 96.0% for penicillin and 98.0% for tetracycline-resistant, and 10.0% (5/50) were resistant to azithromycin. All cephalosporin-DS isolates were resistant to ciprofloxacin but sensitive to spectinomycin. The predominant MLSTs were ST7363 (16%, 8/50), ST1903 (14%, 7/50), ST1901 (12%, 6/50), and ST7365 (10%, 5/50). Besides some isolates that failed genotyping (NA), NG-STAR ST1143 (n = 6) and NG-MAST ST17748 (n = 4) were the most prevalent. Twelve isolates with mosaic penA-60.001 allele retained the most elevated cephalosporin MIC (Minimum Inhibitory Concentration). Phylogenetic analysis revealed that epidemic penA-60.001 clones, either domestic or foreign, had spread to nine cities in Guangdong, and 9/12 clones were from the Pearl River Delta region.

CONCLUSIONS

N. gonorrhoeae with cephalosporins-DS was extensively disseminated in Guangdong, Southern China, requiring strict surveillance.

Evaluation of Neisseria gonorrhoeae Isolates Susceptibility to Antibiotics in Zhejiang Province Since 2007

Objective

This study aimed to assess the drug susceptibility of clinical isolates of Neisseria gonorrhoeae to spectinomycin, ceftriaxone and azithromycin. Moreover, the temporal trends in the minimum inhibitory concentration (MIC) of five antibiotics from Zhejiang, China, are also in the scope of this study.

Methods

A total of 1710 gonococcal clinical strains were collected between 2007 and 2021 from health-care institutions in Zhejiang. The MICs of ceftriaxone, azithromycin, spectinomycin, penicillin and ciprofloxacin were assessed by agar dilution method on 1710 Neisseria gonorrhoeae isolates. Count data were expressed as strains and rates, and MICs distribution was elucidated using descriptive statistics.

Results

The total resistance rates of gonococci to azithromycin, spectinomycin, penicillin and ciprofloxacin in this study were 19.3%, 0.3%, 75.4% and 99.7%, respectively.

Conclusion

The in vitro results showed a high prevalence of resistance to ciprofloxacin and penicillin. Azithromycin resistance rate has exceeded 5%, suggested a high prevalence of resistance. Ceftriaxone and spectinomycin are suggested based on this study for the treatment of Neisseria gonorrhoeae in Zhejiang.

Global status of Azithromycin and Erythromycin Resistance Rates in Neisseria gonorrhoeae: A Systematic Review and Meta-analysis

Background: The widespread development of antibiotic resistance or decreased susceptibility in Neisseria gonorrhoeae (NG) infection is a global and significant human public health issue. Objectives: Therefore, this meta-analysis aimed to estimate worldwide resistance rates of NG to the azithromycin and erythromycin according to years, regions, and antimicrobial susceptibility testing (AST). Methods: We systematically searched the published studies in PubMed, Scopus, and Embase from 1988 to 2021. All analyses were conducted using Stata software. Results: The 134 reports included in the meta-analysis were performed in 51 countries and examined 165,172 NG isolates. Most of the included studies were from Asia (50 studies) and Europe (46 studies). In the metadata, the global prevalence over the past 30 years were 6% for azithromycin and 48% for erythromycin. There was substantial change in the prevalence of macrolides NG resistance over time (P <0.01). In this metadata, among 58 countries reporting resistance data for azithromycin, 17 (29.3%) countries reported that >5% of specimens had azithromycin resistance. Conclusions: The implications of this study emphasize the rigorous or improved antimicrobial stewardship, early diagnosis, contact tracing, and enhanced intensive global surveillance system are crucial for control of further spreading of gonococcal emergence of antimicrobial resistance (AMR).

Emergence and Genomic Characterization of Neisseria gonorrhoeae Isolates with High Levels of Ceftriaxone and Azithromycin Resistance in Guangdong, China, from 2016 to 2019

Currently, antibiotic resistance (especially ceftriaxone and azithromycin dual resistance) in Neisseria gonorrhoeae is the main obstacle affecting the efficacy of treatment. As analysis of drug sensitivity, molecular features, and dissemination of dual-resistant strains is important for gonococcal prevention and control, MIC, genotyping, and genome analysis were conducted to reveal the molecular characteristics and phylogeny of N. gonorrhoeae isolates. During 2016 to 2019, 5 out of 4,113 strains were defined as dual-resistant clones, with ceftriaxone MICs of 0.25 to ≥1 mg/L and azithromycin MICs of 2 to ≥2,048 mg/L. In particular, two strains with a ceftriaxone MIC above 0.5 mg/L were characterized as penA-60.001 FC428-related clones, and two isolates with a high-level azithromycin MIC above 1,024 mg/L featuring a 23S rRNA mutation were identified. Furthermore, phylogenetic analysis confirmed that the dual-resistant strains were closer to the evolutionary origin of F89 in France, global FC428-related clones, and high-level dual-resistant clones in Australia and the United Kingdom. Dual-resistant strains, including FC428-related clones and high-level azithromycin-resistant clones, have circulated in Guangdong, China. The ability of laboratories to perform real-time drug susceptibility and genetic analyses should be strengthened to monitor the spread of threatening strains. IMPORTANCE Here, we report five sporadic dual-resistant isolates, including FC428-related ceftriaxone-resistant clones with MICs of ≥0.5 mg/L and high-level azithromycin resistance with MICs of ≥1,024 mg/L. This study highlights that dual-resistant clones with the same evolutionary origin as FC428, A2735, and F89 have circulated in Guangdong, China, which suggests that the capacity for antibiotic resistance testing and genome analysis should be strengthened in daily epidemiological surveillance.

Moenomycin is broadly active against multidrug-resistant Neisseria gonorrhoeae and clears an infection from a murine vaginal tract infection model

OBJECTIVES

Ceftriaxone therapy for gonorrhoea has become under increasing pressure due to waning susceptibility levels and emergence of high-level resistant strains such as the FC428 clone. Moenomycin was recently identified to display potent anti-gonococcal activity against some reference strains. Therefore, the aim of this study was to investigate moenomycin in vitro and in vivo antimicrobial activity.

METHODS

Moenomycin in vitro antimicrobial activity was investigated against 575 clinical isolates, including strains associated with the FC428 clone, using the agar dilution method. Moenomycin in vivo activity was investigated in a mouse vaginal tract gonococcal infection model.

RESULTS

The moenomycin MIC range for the strain collection was 0.004-0.06 mg/L, with a MIC50 of 0.016 mg/L and a MIC90 of 0.03 mg/L. The correlation between moenomycin and ceftriaxone susceptibility levels was poor (R = 0.13), while the fractional inhibitory concentration index (FICI) resulted in indifference for all tested strains. Therefore, development of cross-resistance between moenomycin and ceftriaxone is unlikely for N. gonorrhoeae. Determination of the moenomycin mode of activity against N. gonorrhoeae by time-kill assays showed that moenomycin is bactericidal, with over 104-fold inactivation observed after 4 h exposure. Finally, an intramuscular moenomycin dose of 10 mg/kg given on 2 consecutive days was able to clear a gonococcal infection in a mouse vaginal tract infection model within 1-3 days after the second dose, which was significantly faster than for mice treated with the vehicle control (P < 0.0001).

CONCLUSIONS

Moenomycin displays potent in vitro and in vivo antimicrobial activity against N. gonorrhoeae, warranting further exploration as alternative therapy.

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.

In Vitro Activity of Ertapenem against Neisseria gonorrhoeae Clinical Isolates with Decreased Susceptibility or Resistance to Extended-Spectrum Cephalosporins in Nanjing, China (2013 to 2019)

Neisseria gonorrhoeae isolates collected in Nanjing, China, that possessed decreased susceptibility (or resistance) to extended-spectrum cephalosporins (ESCs) were examined for susceptibility to ertapenem, and their sequence types were determined. Ceftriaxone and cefixime MICs of ≥0.125 mg/L and ≥0.25 mg/L, respectively, were first determined in 259 strains isolated between 2013 and 2019, and then MICs of ertapenem were measured using the antimicrobial gradient Epsilometer test (Etest). Also, genetic determinants of ESC resistance were identified and N. gonorrhoeae multiantigen sequence typing (NG-MAST) was performed to analyze associations with ertapenem susceptibility. All isolates displayed ertapenem MICs between 0.006 mg/L and 0.38 mg/L; the overall MIC₅₀ and MIC₉₀ were 0.032 mg/L and 0.125 mg/L, respectively. Forty-four (17.0%) isolates displayed ertapenem MICs of ≥0.125 mg/L; 10 (3.9%) had MICs of ≥0.25 mg/L. The proportion of isolates with ertapenem MICs of ≥0.125 mg/L increased from 4.0% in 2013 to 20.0% in 2019 (χ² = 24.144, P < 0.001; chi-square test for linear trend). The penA mosaic allele was present in a significantly higher proportion of isolates with ertapenem MICs of ≥0.125 mg/L than of isolates with MICs of ≤0.094 mg/L) (97.7% versus 34.9%, respectively; χ² = 58.158, P < 0.001). ST5308 was the most prevalent NG-MAST type (8.5%); ST5308 was also significantly more common among isolates with ertapenem MICs of ≥0.125 mg/L than isolates with MICs of ≤0.094 mg/L (22.7% and 5.6%, respectively; χ² = 13.815, P = 0.001). Ertapenem may be effective therapy for gonococcal isolates with decreased susceptibility or resistance to ESCs and isolates with identifiable genetic resistance determinants.

Mechanism of action, resistance, synergism, and clinical implications of azithromycin

Background

Azithromycin (AZM), sold under the name Zithromax, is classified as a macrolide. It has many benefits due to its immunomodulatory, anti‐inflammatory, and antibacterial effects. This review aims to study different clinical and biochemisterial aspects and properties of this drug which has a priority based on literature published worldwide.

Methods

Several databases including Web of Science, Google Scholar, PubMed, and Scopus were searched to obtain the relevant studies.

Results

AZM mechanism of action including the inhibition of bacterial protein synthesis, inhibition of proinflammatory cytokine production, inhibition of neutrophil infestation, and macrophage polarization alteration, gives it the ability to act against a wide range of microorganisms. Resistant organisms are spreading and being developed because of the irrational use of the drug in the case of dose and duration. AZM shows synergistic effects with other drugs against a variety of organisms. This macrolide is considered a valuable antimicrobial agent because of its use as a treatment for a vast range of diseases such as asthma, bronchiolitis, COPD, cystic fibrosis, enteric infections, STIs, and periodontal infections.

Conclusions

Our study shows an increasing global prevalence of AZM resistance. Thus, synergistic combinations are recommended to treat different pathogens. Moreover, continuous monitoring of AZM resistance by registry centers and the development of more rapid diagnostic assays are urgently needed.

Markedly Increasing Antibiotic Resistance and Dual Treatment of Neisseria gonorrhoeae Isolates in Guangdong, China, from 2013 to 2020

The emergence of multidrug resistance in Neisseria gonorrhoeae is concerning, especially the cooccurrence of azithromycin resistance and decreased susceptibility to extended-spectrum cephalosporin. This study aimed to confirm the antibiotic resistance trends and provide a solution for N. gonorrhoeae treatment in Guangdong, China. A total of 5,808 strains were collected for assessment of antibiotic MICs. High resistance to penicillin (53.80 to 82%), tetracycline (88.30 to 100%), ciprofloxacin (96 to 99.8%), cefixime (6.81 to 46%), and azithromycin (8.60 to 20.03%) was observed. Remarkably, spectinomycin and ceftriaxone seemed to be the effective choices, with resistance rates of 0 to 7.63% and 2.00 to 16.18%, respectively. Moreover, the rates of azithromycin resistance combined with decreased susceptibility to ceftriaxone and cefixime reached 9.28% and 8.64%, respectively. Furthermore, genotyping identified NG-STAR-ST501, NG-MAST-ST2268, and MLST-ST7363 as the sequence types among representative multidrug-resistant isolates. Evolutionary analysis showed that FC428-related clones have spread to Guangdong, China, which might be a cause of the rapid increase in extended-spectrum cephalosporin resistance currently. Among these strains, the prevalence of N. gonorrhoeae was extremely high, and single-dose ceftriaxone treatment might be a challenge in the future. To partially relieve the treatment pressure, a susceptibility test for susceptibility to azithromycin plus extended-spectrum cephalosporin dual therapy was performed. The results showed that all the representative isolates could be effectively killed with the coadministration of less than 1 mg/liter azithromycin and 0.125 mg/liter extended-spectrum cephalosporin, with a synergistic effect according to a fractional inhibitory concentration (FIC) of <0.5. In conclusion, dual therapy might be a powerful measure to treat refractory N. gonorrhoeae in the context of increasing antibiotic resistance in Guangdong, China.

Evaluation of Neisseria gonorrhoeae Isolates Susceptibility to Tetracycline Antibiotics from 9 Provinces in China Since 2020

Purpose

Methods

Results

Conclusion

Dissemination and genome analysis of high-level ceftriaxone-resistant penA 60.001 Neisseria gonorrhoeae strains from the Guangdong Gonococcal Antibiotics Susceptibility Programme (GD-GASP), 2016-2019

Background: After Neisseria gonorrhoeae FC428 was first found in Japan, ceftriaxone-resistant strains disseminated globally, and the gonococcal resistance rate increased remarkably. Epidemiological investigations are greatly significant for the analysis of antimicrobial resistance (AMR) trends, molecular features and evolution. Objectives: To clarify the AMR trend from 2016–2019 and reveal the molecular characteristics and evolution of ceftriaxone-resistant penA 60.001 isolates. Methods: The minimum inhibitory concentrations (MICs) of antibiotics against 4113 isolates were detected by the agar dilution method. N. gonorrhoeae multiantigen sequence typing (NG-MAST), multilocus sequence typing (MLST) and N.gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were used to identify the sequence types. Genome analysis was conducted to analyze resistance genes, virulence factors, and evolutionary sources. Results: Isolates with decreased ceftriaxone susceptibility have increased from 2.05% (2016) to 16.18% (2019). Six ceftriaxone-resistant isolates possessing penA 60.001 appeared in Guangdong Province, and were resistant to ceftriaxone, penicillin, tetracycline, ciprofloxacin and cefixime, but susceptible to azithromycin and spectinomycin. Single-nucleotide polymorphisms (SNPs) in the porB gene were the major cause of different NG-MAST types. ST1903 was the main NG-STAR genotype and only strain-ZH545 was ST7365, with molecular features consistent with the MICs. Furthermore, different MLSTs suggested diverse evolutionary sources. Genome analysis revealed a set of virulence factors along with the resistance genes “penA” and “blaTEM-1B”. Half of penA 60.001 strains were fully mixed with global FC428-related strains. Conclusions: Global FC428-related clones have disseminated across Guangdong, possibly causing decreased ceftriaxone susceptibility. Enhanced gonococcal surveillance will help elucidate the trajectory of transmission and curb further dissemination.

Evaluation of the Accuracy of Various Disks and Strips for Rapid Culture-Based Gonococcal Antimicrobial Susceptibility Screening Tests in China

Purpose

Neisseria gonorrhoeae, resistant to the first-line treatment option ceftriaxone, is widespread in China from 2016. Nowadays, diverse reagents of disks and strips for rapid gonococcal antimicrobial susceptibility tests used in clinics are culture-based disks diffusion and gradient strips methods. This study aimed to evaluate the accuracy, quality, and availability of almost all disks and strips acquired in the Chinese market and serve as a reference for clinical selection.

Methods

We tested the performance of 15 commercial disks and 9 commercial gradient strips acquired in China, compared with traditional agar dilution method. The overall performance was evaluated by the categorical agreement. The reagent accuracy of gradient strips was assessed by the essential agreement.

Results

A total of 167 gonococcal isolates were used to evaluate antimicrobial disks from three brands. The overall categorical agreements were 71.7% to 81.8% for ceftriaxone, less than 58% for cefixime, 100% for spectinomycin, over 98% for ciprofloxacin, below 70.5% for penicillin, and 73.3% to 81.8% for tetracycline. A total of 81 isolates were tested for different gradient strips. Categorical agreements were over 96% for ceftriaxone, 86.2% for azithromycin, 62.3% to 67.1% for penicillin, 41.9% to 67.5% for tetracycline, and 95% for ciprofloxacin. Essential agreements were 57.7% to 87.3% for ceftriaxone, 70% for azithromycin, 64.9% to 68.4% for penicillin, 51.8% to 71.2% for tetracycline, and 91.3% for ciprofloxacin.

Conclusion

Rapid test reagents of disks and strips based on gonococcal culture have suboptimal performance. Disk diffusion for spectinomycin or ciprofloxacin can be recommended for clinical individualized prescription. The gradient strips are of great value to identify ceftriaxone-resistant gonococcal strains. Furthermore, abundant improvements are required for many reagents to further optimize their accuracy till the fulfillment of molecular detection.

Multidrug-resistant Neisseria gonorrhoeae infection in heterosexual men with reduced susceptibility to ceftriaxone, first report in Thailand

The global rapid emergence of azithromycin/ceftriaxone resistant Neisseria gonorrhoeae threatens current recommend azithromycin/ceftriaxone dual therapy for gonorrhea to ensure effective treatment. Here, we identified the first two N. gonorrhoeae isolates with decreased ceftriaxone susceptibility in Thailand. Among 134 N. gonorrhoeae isolates collected from Thai Red Cross Anonymous Clinic, Bangkok, two isolates (NG-083 and NG-091) from urethral swab in male heterosexual patients had reduced susceptibility to ceftriaxone (MICs of 0.125 mg/L). Both were multidrug resistant and strong biofilm producers with ceftriaxone tolerance (MBEC > 128 mg/L). NG-083 and NG-091 remained susceptible to azithromycin (MIC of 1 mg/L and 0.5 mg/L, respectively). Reduced susceptibility to ceftriaxone was associated with alterations in PBP2, PBP1, PorB, MtrR, and mtrR promoter region. NG-083 belonged to sequence type (ST) 7235 and NG-091 has new allele number of tbpB with new ST. Molecular docking revealed ceftriaxone weakly occupied the active site of mosaic XXXIV penicillin-binding protein 2 variant in both isolates. Molecular epidemiology results revealed that both isolates display similarities with isolates from UK, USA, and The Netherlands. These first two genetically related gonococcal isolates with decreased ceftriaxone susceptibility heralds the threat of treatment failure in Thailand, and importance of careful surveillance.

Antimicrobial Susceptibility of Ertapenem in Neisseria gonorrhoeae Isolates Collected Within the China Gonococcal Resistance Surveillance Programme (China-GRSP) 2018

Purpose

This study aimed to determine the minimum inhibitory concentrations (MICs) of ertapenem on Neisseria gonorrhoeae collected from eight Chinese provinces in 2018.

Methods

The MICs of ertapenem on 503 Neisseria gonorrhoeae isolates (415 isolates selected randomly and 88 isolates selected with preference) were measured using the agar dilution method. For comparison, the MICs of ceftriaxone and azithromycin were detected.

Results

Among 415 randomly selected isolates, the MIC range for ertapenem was from ≤0.008 mg/L to 0.5 mg/L. The corresponding MIC₅₀ and MIC₉₀ were 0.06 and 0.125 mg/L, respectively. Twelve of 415 isolates (2.9%) exhibited MIC values ≥0.25 mg/L, and only one isolate (0.2%) had a MIC of 0.5 mg/L. By comparing all 503 tested isolates, a correlation of r = 0.487 (P <0.001) between ertapenem and ceftriaxone MIC was observed, and the correlation between MICs of ertapenem and azithromycin was low (r = -0.12, P = 0.007). In 24 ceftriaxone-decreased susceptibility isolates, four isolates (16.7%) showed a MIC ≥0.25 mg/L for ertapenem. In 85 azithromycin resistant isolates, three isolates (3.5%) showed a MIC ≥0.25 mg/L for ertapenem.

Conclusion

The in vitro results suggest that ertapenem has satisfactory susceptibility in isolates collected from eight provinces in China; hence, it might be a promising treatment option for resistant gonococcal infections.

Substitutions in SurA and BamA Lead to Reduced Susceptibility to Broad Range Antibiotics in Gonococci

There is growing concern about the emergence and spread of multidrug-resistant Neisseria gonorrhoeae. To effectively control antibiotic-resistant bacterial pathogens, it is necessary to develop new antimicrobials and to understand the resistance mechanisms to existing antibiotics. In this study, we discovered the unexpected onset of drug resistance in N. gonorrhoeae caused by amino acid substitutions in the periplasmic chaperone SurA and the β-barrel assembly machinery component BamA. Here, we investigated the i19.05 clinical isolate with mutations in corresponding genes along with reduced susceptibility to penicillin, tetracycline, and azithromycin. The mutant strain NG05 (surAmut bamAmut, and penAmut) was obtained using the pan-susceptible n01.08 clinical isolate as a recipient in the transformation procedure. Comparative proteomic analysis of NG05 and n01.08 strains revealed significantly increased levels of other chaperones, Skp and FkpA, and some transport proteins. Efflux pump inhibition experiments demonstrated that the reduction in sensitivity was achieved due to the activity of efflux pumps. We hypothesize that the described mutations in the surA and bamA genes cause the qualitative and quantitative changes of periplasmic chaperones, which in turn alters the function of synthesized cell envelope proteins.

The Accuracy of Molecular Detection Targeting the Mutation C2611T for Detecting Moderate-Level Azithromycin Resistance in Neisseria gonorrhoeae: A Systematic Review and Meta-Analysis

BACKGROUND

Neisseria gonorrhoeae (N. gonorrhoeae) is now recognized as a commonly reported sexually transmitted pathogen, and the increasing drug resistance of N. gonorrhoeae has become a serious public health problem. The accuracy of molecular detection for detecting moderate-level azithromycin resistance is not well-established. We summarized the data from studies of the N. gonorrhoeae 23S rRNA mutation at position 2611 with azithromycin resistance to determine the relationship between the mutation and resistance.

METHODS AND FINDINGS

In this systematic review and meta-analysis, two researchers independently searched six databases for studies with data for the azithromycin minimum inhibitory concentrations (MICs) and the 23S rRNA mutation C2611T of each N. gonorrhoeae isolate. Since the breakpoint of moderate-level resistance to azithromycin (ML-AzmR) was not determined, we divided the moderate level into two groups according to the range of MICs (moderate resistance limited to 2-128 mg/L or 4-128 mg/L) for data extraction. A random-effects model was used to calculate the pooled sensitivity rate, the specificity rate, the pooled positive likelihood ratio (PLR), the negative likelihood ratio (NLR), and the diagnostic odds ratio (DOR). Meta-regression analyses by detection method, isolates sampling (a random sample or not), location, and sample size were performed to explore the possible causes of heterogeneity. The potential publication bias of the included studies was conducted by the Deeks' test. We included 20 studies in our study: 20 studies have data of N. gonorrhoeae with MICs between 2 and 128 mg/L with mutation or without mutation at position 2611(4759 samples), and 14 studies have data of N. gonorrhoeae with MICs between 4 and 128 mg/L (3367 samples). In the group with the moderate level of 2-128 mg/L, the pooled sensitivity rate of the molecular assays was determined to be 71.9% (95% CI, 67.6-74%), the pooled specificity rate was 98.7% (95% CI, 98.2-99.0%), and the DOR ranged from 55.0 to 351.3 (mean, 139.1). In the 4-128 mg/L group, the pooled sensitivity rate was 91.9% (95% CI, 88.9-94.2%), the pooled specificity rate was 95.9% (95% CI, 95.1-96.6%), and the DOR ranged from 41.9 to 364.1 (mean, 123.6).

CONCLUSION

Through this meta-analysis, we found that the C2611T mutation of 23S rRNA is valuable for the molecular diagnostic of moderate-level azithromycin resistance (ML-AzmR) in N. gonorrhoeae, especially when the moderate level is set at 4-128 mg/L. This rapid molecular detection method can be used for the rapid identification of ML-AzmR isolates in the clinic.

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.

Sustained transmission of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone in China

BACKGROUND

Ceftriaxone resistance in Neisseria gonorrhoeae has become an imminent threat to effective control of gonorrhoea globally. In recent years, the ceftriaxone-resistant FC428 clone has shown international dissemination. After our first report of the FC428 clone in China in 2016, we now describe another six cases of FC428-related ceftriaxone-resistant N. gonorrhoeae isolates from 2017 and 2018.

OBJECTIVES

To identify the phenotypic and molecular characteristics of newly reported ceftriaxone-resistant isolates in China and to investigate the relationship between these isolates and FC428 clones reported globally.

METHODS

Antimicrobial susceptibility to ceftriaxone, cefixime, azithromycin, spectinomycin, penicillin, ciprofloxacin and tetracycline was determined by the agar dilution method. N. gonorrhoeae multi-antigen sequence typing (NG-MAST), MLST and N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were performed for genotyping and SNPs extracted from whole-genome sequences were used for phylogenetic analysis.

RESULTS

All isolates were resistant to ceftriaxone, cefixime, penicillin, tetracycline and ciprofloxacin, but were susceptible to azithromycin and spectinomycin. NG-MAST, MLST and NG-STAR genotyping showed that all isolates shared identical or similar STs (<10 bp difference) to FC428 (NG-MAST ST3435, MLST ST1903, NG-STAR ST233) and contained the same mosaic penA allele 60.001. Phylogenetic analysis showed the Chinese isolates spreading in the whole phylogenetic tree and fully mixed with other international isolates. Half of the Chinese isolates were more closely related (<100 SNPs) to Japanese isolates than other international isolates.

CONCLUSIONS

The newly reported cases in China were related to the internationally spreading FC428 clone. These isolates might have played a central role in international transmission of the FC428 clone. High ceftriaxone doses (1-2 g) still provide effective therapy.

Emergence and genomic characterization of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone in Chengdu, China

OBJECTIVES

To verify the contribution of the globally disseminated Neisseria gonorrhoeae FC428 clone to the emergence of ceftriaxone resistance in Chengdu in south-west China during 2018.

METHODS

Antimicrobial susceptibility of the N. gonorrhoeae isolates to six antibiotics was determined using the agar dilution method. A real-time PCR assay and WGS were used to identify the FC428 clone. Phylogenomic and molecular antimicrobial resistance analyses were conducted to characterize the transmission and evolution of related strains.

RESULTS

Four out of 112 N. gonorrhoeae isolates were confirmed as the ceftriaxone-resistant FC428 clone. Phylogenomic analysis revealed that they resulted from multiple introductions and subsequent local transmissions. The strains have undergone further evolutions characterized by the accumulation of mutations in resistance-associated genes and/or the acquisition of plasmids encoding penicillin and tetracycline resistance genes.

CONCLUSIONS

The N. gonorrhoeae FC428 clone has spread to south-west China. Efforts should be made to enhance gonococcal antimicrobial surveillance to control further dissemination of this successful clone at both local and national levels.

A multiplex assay for characterization of antimicrobial resistance in Neisseria gonorrhoeae using multi-PCR coupled with mass spectrometry

BACKGROUND

Complicated mechanisms and variable determinants related to drug resistance pose a major challenge to obtain comprehensive antimicrobial resistance (AMR) profiles of Neisseria gonorrhoeae. Meanwhile, cephalosporin-resistant mosaic penA alleles have been reported worldwide. Therefore, it is urgent to monitor the expansion of cephalosporin-resistant mosaic penA alleles.

OBJECTIVES

To develop a comprehensive high-throughput method to efficiently screen AMR determinants.

METHODS

We developed a method based on multiplex PCR with MALDI-TOF MS, which can simultaneously screen for 24 mutations associated with multiple antimicrobial agents in 19 gonococcal AMR loci (NG-AMR-MS). The performance of the NG-AMR-MS method was assessed by testing 454 N. gonorrhoeae isolates with known MICs of six antibiotics, eight non-gonococcal Neisseria strains, 214 clinical samples and three plasmids with a confirmed mosaic penA allele.

RESULTS

The results show that NG-AMR-MS had a specificity of 100% with a sensitivity as low as 10 copies per reaction (except for PorB A121D/N/G, 100 copies per reaction). For clinical samples with gonococcal load >5 copies/μL, the method can accurately identify 20 AMR mutations. In addition, the method successfully detected specific cephalosporin-resistant strains with the A311V mutation in the penA allele.

CONCLUSIONS

Our high-throughput method can provide comprehensive AMR profiles within a multiplex format. Furthermore, the method can be directly applied to screening for AMR among clinical samples, serving as an effective tool for overall monitoring of N. gonorrhoeae AMR and also provides a powerful means to comprehensively improve the level of monitoring.

A Screen of Natural Product Extracts Identifies Moenomycin as a Potent Antigonococcal Agent

Increasing multidrug resistance in Neisseria gonorrheae is a growing public health crisis. Resistance to the last line therapies, cephalosporins and azithromycin, are of particular concern, fueling the need to discover new treatments. Here, we identified the phosphoglycolipid moenomycin from a screen of microbial natural products against drug-resistant N. gonorrheae as a potent antigonococcal agent. Moenomycin demonstrates excellent activity (MIC = 0.004-0.03 μg/mL) against a variety of multidrug-resistant N. gonorrheae. Importantly, moenomycin, thought to be a Gram-positive specific antibiotic, penetrates the Gram-negative gonococcal outer membrane. Moenomycin causes intracellular accumulation of peptidoglycan precursors, cell blebbing, and rupture of the cell envelope, all consistent with cell wall biosynthesis inhibition. Serial bacterial exposure to moenomycin for 14 days revealed slow development of resistance (MIC_Day14 = 0.03-0.06 μg/mL), unlike the clinically used drug azithromycin. Our results offer the potential utility of moenomycin as a lead for antigonococcal therapeutic candidates and warrant further investigation.

Choosing New Therapies for Gonorrhoea: We Need to Consider the Impact on the Pan-Neisseria Genome. A Viewpoint

The development of new gonorrhoea treatment guidelines typically considers the resistance-inducing effect of the treatment only on Neisseria gonorrhoeae. Antimicrobial resistance in N. gonorrhoeae has, however, frequently first emerged in commensal Neisseria species and then been passed on to N. gonorrhoeae via transformation. This creates the rationale for considering the effect of gonococcal therapies on resistance in commensal Neisseria. We illustrate the benefits of this pan-Neisseria strategy by evaluating three contemporary treatment options for N. gonorrhoeae-ceftriaxone plus azithromycin, monotherapy with ceftriaxone and zoliflodacin.

Typing of Neisseria Gonorrhoeae isolates in Shenzhen, China from 2014-2018 reveals the shift of genotypes associated with antimicrobial resistance

The growing antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a serious global threat to gonococcal therapy. Molecular typing is an ideal tool to reveal the association between specific genotype and resistance phenotype that provides effective data for tracking the transmission of resistant clones of N. gonorrhoeae In our study, we aimed to describe the molecular epidemiology of AMR and the distribution of resistance-associated genotypes in Shenzhen during 2014-2018. In total, 909 isolates were collected from Shenzhen from 2014-2018. Two typing schemes, multilocus sequence typing (MLST) and N. gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR), were performed for all isolates. The distribution of resistance-associated genotypes was described using goeBURST analysis combined with data of logistic regression. Among 909 isolates, ST₈₁₂₃, ST₇₃₆₃, ST₁₉₀₁, ST₇₃₆₅, and ST₇₃₆₀ were most the common MLST sequence types (STs), and ST₃₄₈, ST₂₄₇₃, ST₄₉₇, and ST₁₉₉ were the most prevalent NG-STAR STs. The logistic regression analysis showed that NG-STAR_ST497, MLST_ST7365, and MLST_ST7360 were typically associated with decreased susceptibility to ceftriaxone. Furthermore, the internationally spreading ESC-resistant clone MLST_ST1901 has been prevalent at least in 2014 in Shenzhen and showed a significant increase during 2014-2018. Additionally, MLST_ST7363 owns the potential to become the next internationally spreading ceftriaxone-resistant ST. In conclusions, we performed a comprehensive epidemiological study to explore the correlation between AMR and specific STs, which provided important data for future studies of the molecular epidemiology of AMR in N. gonorrhoeae Besides, these findings provide insight for adjusting surveillance strategies and therapy management in Shenzhen.

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.

Widespread Use of High-dose Ceftriaxone Therapy for Uncomplicated Gonorrhea Without Reported Ceftriaxone Treatment Failure: Results From 5 Years of Multicenter Surveillance Data in China

BACKGROUND

Antimicrobial resistance to Neisseria gonorrhoeae has emerged for each of the antibiotics recommended as first-line therapies following their introduction into clinical practice. To improve rational and effective clinical antibiotic treatment, we analyzed the prescription patterns of antibiotics and their therapeutic effect in the treatment of uncomplicated gonorrhea in China.

METHODS

We obtained data from a follow-up multicenter surveillance program. Multinomial logistic regression analyses were conducted to explore the associations between demographic/clinical variables with the levels of sensitivity to ceftriaxone and prescription of high-dose ceftriaxone.

RESULTS

In this study, 1686 patients infected with N. gonorrhoeae were recruited in a surveillance network during 1 January 2013 through 31 December 2017 in 7 hospitals distributed in 5 provinces. The prevalence of isolates with decreased susceptibility to ceftriaxone was 9.8% (131/1333), fluctuating between 5.6% and 12.1%. Injectable ceftriaxone was chosen as the first-line treatment among 83.1% of patients, and most of them (72.7% [1018/1401]) received >1000 mg dosage. Patients who were previously infected with gonorrhea or other sexually transmitted infections (adjusted odds ratio [AOR], 1.618 [95% confidence interval {CI}, 1.11-2.358]; AOR, 2.08 [95% CI, 1.41-3.069]) or who already used antibiotics for this infection (AOR, 1.599 [95% CI, 1.041-2.454]) were associated with a higher prescribed ceftriaxone dosage. All of the patients recruited in this study were cured regardless of the isolates' susceptibility to ceftriaxone or the dosage of ceftriaxone they received.

CONCLUSIONS

No ceftriaxone treatment failure for uncomplicated gonorrhea was reported in China; however, high-dose ceftriaxone was widely used in China. Its impacts need further study.

Evaluation of Drugs with Therapeutic Potential for Susceptibility of Neisseria Gonorrhoeae Isolates from 8 Provinces in China from 2018

PURPOSE

The study aimed to evaluate meropenem, fosfomycin, berberine hydrochloride, and doxycycline minimum inhibitory concentrations (MICs) of Neisseria gonorrhoeae collected from eight provinces in China in 2018.

METHODS

The MICs of 540 Neisseria gonorrhoeae isolates (451 isolates selected randomly and 89 isolates selected with preference) were determined to meropenem, fosfomycin, berberine hydrochloride, and doxycycline using the agar dilution method, and the MICs of ceftriaxone and azithromycin were detected for comparison.

RESULTS

Among 451 randomly selected isolates, the MIC90 was 0.06 mg/L for meropenem, 64 mg/L for fosfomycin, 64 mg/L for berberine hydrochloride, and 16 mg/L for doxycycline. All isolates showed the MIC ≤ 0.125 mg/L to meropenem, 13 isolates (2.9%) showed MIC > 64 mg/L to fosfomycin, 8 isolates (1.8%) demonstrated MIC > 64 mg/L to berberine hydrochloride, and 271 isolates (60.1%) demonstrated MIC > 1 mg/L to doxycycline. Comparing all 540 tested isolates, a correlation of r = 0.50 (P < 0.001) between meropenem and ceftriaxone MIC was observed. In 24 ceftriaxone-decreased susceptibility isolates, all isolates showed an MIC ≤ 0.125 mg/L for meropenem, 1 isolate (4.2%) showed an MIC > 64 mg/L for fosfomycin, 1 isolate (4.2%) showed an MIC > 64 mg/L for berberine hydrochloride, and 13 isolates (54.2%) showed an MIC > 1 mg/L for doxycycline. In 87 azithromycin resistant isolates, all isolates showed an MIC ≤ 0.125 mg/L for meropenem, 2 isolates (2.3%) showed an MIC > 64 mg/L for fosfomycin, 4 isolates (4.6%) showed an MIC > 64 mg/L for berberine hydrochloride, and 64 isolates (73.6%) showed an MIC > 1 mg/L for doxycycline.

CONCLUSION

The in vitro results suggest that meropenem might be a promising treatment option for resistant gonococcal infections, while the effects of fosfomycin and berberine hydrochloride should be further evaluated as potential therapeutic agents. The effectiveness of these drugs in animal experiments and clinical use may need further study.

Impact of the gonococcal FC428 penA allele 60.001 on ceftriaxone resistance and biological fitness

Global dissemination of the Neisseria gonorrhoeae ceftriaxone-resistant FC428 clone jeopardizes the currently recommended ceftriaxone-based first-line therapies. Ceftriaxone resistance in the FC428 clone has been associated with the presence of its mosaic penA allele 60.001. Here we investigated the contribution penA allele 60.001 to ceftriaxone resistance and its impact on biological fitness. Gonococcal isolates expressing penA allele 60.001 and mosaic penA allele 10.001, which is widespread in the Asia-Pacific region and associated with reduced susceptibility to ceftriaxone and cefixime, were genetic engineered to exchange their penA alleles. Subsequent antimicrobial susceptibility analyses showed that mutants containing penA 60.001 displayed 8- to 16-fold higher ceftriaxone and cefixime minimal inhibitory concentrations (MICs) compared with otherwise isogenic mutants containing penA 10.001. Further analysis of biological fitness showed that in vitro liquid growth of single strains and in the competition was identical between the isogenic penA allele exchange mutants. However, in the presence of high concentrations of palmitic acid or lithocholic acid, the penA 60.001-containing mutants grew better than the isogenic penA 10.001-containing mutants when grown as single strains. In contrast, the penA 10.001 mutants outcompeted the penA 60.001 mutants when grown in competition at slightly lower palmitic acid or lithocholic acid concentrations. Finally, the penA 60.001 mutants were outcompeted by their penA 10.001 counterparts for in vivo colonization and survival in a mouse vaginal tract infection model. In conclusion, penA allele 60.001 is essential for ceftriaxone resistance of the FC428 clone, while its impact on biological fitness is dependent on the specific growth conditions.

Shanghai Neisseria gonorrhoeae Isolates Exhibit Resistance to Extended-Spectrum Cephalosporins and Clonal Distribution

The emergence of Neisseria gonorrhoeae strains with resistance (R) to extended-spectrum cephalosporins (ESCs^R) represents a public health threat of untreatable gonococcal infections. This study was designed to determine the prevalence and molecular mechanisms of ESC^R of Shanghai N. gonorrhoeae isolates. A total of 366 N. gonorrhoeae isolates were collected in 2017 in Shanghai. Susceptibility to ceftriaxone (CRO), cefixime (CFM), azithromycin (AZM), ciprofloxacin (CIP), spectinomycin, penicillin, and tetracycline was determined using the agar dilution method. A subset of 124 isolates was subjected to phylogenetic analysis for nine antimicrobial resistance-associated genes, i.e., penA, porB, ponA, mtrR, 23S rRNA, gyrA, parC, 16S rRNA, and rpsE. Approximately 20.0% of the isolates exhibited CFM^R [minimum inhibitory concentration (MIC) >0.125 mg/L], and 5.5% were CRO^R (MIC > 0.125 mg/L). In total, 72.7% of ESC^R isolates were clonal and associated with mosaic penA 10 and 60 alleles. Non-mosaic penA 18 allele and substitutions of PenA A501T, G542S, and PorB1b G213S/Y were observed in non-clonal ESC^R. Approximately 6.8% of the isolates showed AZM MIC above the epidemiological cutoff (ECOFF, 1 mg/L), were associated with 23S rRNA A2059G mutation, and did not exhibit clonal distribution. Almost all isolates were CIP^R (resistance to ciprofloxacin) and associated with GyrA-91/92 and ParC-85/86/87/88/89/91 alterations. Isolates with ParC S88P substitution were clustered into the ESC^R clade. The Shanghai isolates exhibited a high level of ESC^R and distinct resistant patterns.

Should we still use azithromycin for gonorrhoea treatment?

This review presents the evidence for azithromycin in the treatment of gonorrhoea, both as monotherapy and as a component of dual therapy. Uncertainties are explored regarding the efficacy of a dual treatment strategy, combining ceftriaxone and azithromycin, in the context of resistance trends and extra-genital infections. The association between microbiological testing and clinical outcome for the individual patient, and the effect of azithromycin use on other sexually transmissible infections, are considered. Finally, in the absence of imminent new antimicrobials, optimising the dose of azithromycin while maintaining tolerability is discussed.

Surveillance and molecular epidemiology of Neisseria gonorrhoeae isolates in Shenzhen, China, 2010-2017

OBJECTIVES

The development and emergence of antimicrobial resistance in Neisseria gonorrhoeae (NG) have become a major public-health problem worldwide. This study aimed to analyse the antimicrobial susceptibility and molecular characteristics of NG isolates in Shenzhen, China.

METHODS

A total of 1282 NG isolates were consecutively collected between 2010 and 2017. Patient demographic information was also collected. MICs of ceftriaxone, spectinomycin, ciprofloxacin, azithromycin and penicillin were determined by agar dilution. Isolates were genotyped using N. gonorrhoeae multi-antigen sequence typing (NG-MAST).

RESULTS

Among the isolates, 97.4% were resistant to ciprofloxacin and 68.2% to penicillin. Moreover, 5.0% showed decreased susceptibility to ceftriaxone (CRO^D) and 17.3% were resistant to azithromycin (AZM-R); 1.3% were simultaneously CRO^D and AZM-R. All isolates were susceptible to spectinomycin. Increasing ceftriaxone MICs were found from 2010 to 2017. A total of 427 sequence types (STs) and 68 genogroups were identified from 724 isolates. ST5061, ST3741 and ST1766 were observed across the study years. ST14638 (n = 3) was predominant among 32 CRO^D isolates. Prevalent STs were ST5061 (n = 6), ST1866 (n = 5) and ST11133 (n = 5) among 96 AZM-R isolates.

CONCLUSIONS

A high prevalence of isolates resistant to ciprofloxacin and penicillin was found in this study. Azithromycin, one antimicrobial of dual antimicrobial therapy recommended by the WHO, showed a high prevalence of resistance. The other, ceftriaxone, can be used continuously in this region owing to lower resistance levels. However, the emergence of CRO^D and decreasing susceptibility to ceftriaxone indicate that continuous antimicrobial resistance surveillance is essential.

Azithromycin resistant gonococci: a literature review

OBJECTIVE

Gonorrhea is the second most common sexually transmitted bacterial infection (STI) next to Chlamydia. Untreated cases could results in major complications like pelvic inflammatory disease (PID), ectopic pregnancy, infertility, miscarriage, fetal death and congenital infections. Gonorrhea has been treated with antibiotics for more than eight decades. However, the emergence and spread of antimicrobial resistance (AMR) in gonococcus seriously compromises the management of the disease. The aim of this review was to describe the current developments in the field of azithromycin resistant gonococci.

METHODS

Literatures published in English in the last 10 years were retrieved from PubMed, SCOPUS, Google scholar, Cochrane library and the Google databases using relevant searching terms.

RESULTS

Gonococcus is capable of using a number of strategies to confer resistance as the bacterium has an extraordinary capacity to alter its genome. So far the accumulated data on the field showed that the world is heading towards a pandemic of extensively drug-resistant (XDR) gonococcus which is now seems to be evolving into a true "superbug". Hence, in the near future gonorrhea may become untreatable on the international basis unless new drugs become available. An antibiotic resistance in gonococcus has been noted beginning in 1940s against sulfonamides. Since then, resistance has rapidly emerged to penicillins, tetracyclines, macrolides, fluoroquinolones, and cephalosporins. Currently, in most nations, the injectable extended-spectrum cephalosporin (ESC), i.e. ceftriaxone based therapy is the only remaining option for gonorrhea. Based on the WHO and the US-CDC recommendations, countries are increasingly using a combination of cephalosporin and azithromycin for the treatment of gonorrhoea. Azithromycin revolutionized gonoccocal therapy as it shortened treatment time by more than half from 7 to 14 days and improved patient compliance due to high tissue levels and long half-life. However, constantly emerging reports from different parts of the globe showed that N. gonorrhoeae is developing significant level of resistance against azithromycin, and so far more than 33% level of resistance was reported. Two strategies have been commonly implicated in gonococcal resistance against azithromycin: over expression of an efflux pump (due to mutations at mtrR coding region) and decreased antimicrobial affinity (due to mutations in genes encoding the 23S ribosomal subunit).

CONCLUSIONS

With no alternative antimicrobial treatment options for gonorrhoea and only a few new drugs in the development pipeline, it is necessary to monitor drug resistance and optimize treatment regimens regularly. Moreover, investigations for novel drugs should be wired.

Novel education-based intervention to reduce inappropriate antibiotic prescribing for treatment of gonorrhoea in China: protocol for a cluster randomised controlled trial

INTRODUCTION

Inappropriate use of antibiotics to treat gonorrhoea can lead to antibiotic resistance. Education programmes may be helpful for improving physician prescribing behaviours in accordance with treatment guidelines. As traditional education based on printed materials may have limited effect on guideline-based treatment, innovative education strategies are needed. The current trial aims to assess the effectiveness of a novel education intervention to increase guideline-based treatment of gonorrhoea in China.

METHODS AND ANALYSIS

We will conduct a two-arm cluster randomised control trial at 144 hospitals (clusters) in eight Chinese provinces. The intervention will include an online training video developed on the WenJuanXing platform that covers workflows and requirements for managing a patient with uncomplicated gonorrhoea. Outpatient physicians in dermatology (dermatovenerology), urology, andrology and gynaecology will be given access to the video via a quick response code. In hospitals allocated to the control arm, physicians will continue to participate in their standard of care training programme. The primary outcome is the proportion of gonorrhoea antibiotic prescriptions adherent to Chinese national guidelines at the cluster level. In addition, to understand the reasons of physician's non-adherence to the intervention by conducting a questionnaire survey will be considered as the secondary outcome of the study.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Medical Ethics Committee of the Chinese Academy of Medical Sciences Institute of Dermatology (2020-LS-004). All physicians will provide an informed consent prior to participating in the study. Findings of the trial will be disseminated through conferences and peer-reviewed journals, and will be used to develop training programmes for physicians.

TRIAL REGISTRATION NUMBER

ChiCTR2000029591.

Comparison of Microdilution Method with Agar Dilution Method for Antibiotic Susceptibility Test of Neisseria gonorrhoeae

Introduction

Antimicrobial resistance (AMR) of Neisseria gonorrhoeae (N. gonorrhoeae) becomes a grave public health problem in the world. A strengthened Antimicrobial Resistance Surveillance Program is needed to track the trend of AMR development. However, the lack of a proper antimicrobial susceptibility test (AST) method is a barrier to expand the AMR surveillance in China. Traditional agar dilution (AD) method is laborious and E-test strips have no approval license for clinical use. Herein, a Chinese group modified the microdilution (MD) method for clinical ASTs. The objective of this study is to compare the MD method with the AD method for N. gonorrhoeae AST.

Materials and Methods

A total of 166 clinical isolates were tested for antimicrobial susceptibility of ceftriaxone, spectinomycin, azithromycin, ciprofloxacin, tetracycline, and penicillin using MD and AD method simultaneously. Results of MD method were read manually or automatically. Rates of essential agreement (EA), category agreement (CA), minor error, and very major error were compared.

Results

The total EAs (compared with results read manually) of penicillin, tetracycline, ciprofloxacin, spectinomycin, ceftriaxone, and azithromycin were 90.4%, 97.0%, 85.5%, 100.0%, 94%, and 72.3%; and CAs were 82.5%, 94.0%, 100%, 100%, 95.2%, and 94%, respectively.

Conclusion

We conclude that the MD method might be an alternative for clinical AST of N. gonorrhoeae in China. In particular, MD method has the potency of accurate differentiation of isolates resistant to ceftriaxone or azithromycin, which were empirically recommended for gonococcal treatment, but its quality remained suboptimal, and further improvement is needed for clinical use.

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.

<p>Disk-Diffusion Testing Is an Inappropriate Screening Tool for Cephalosporin-Resistant Gonorrhoea Strains in Clinical Practice in China</p>

Purpose

Injectable ceftriaxone and oral cefixime are the last agents effective against Neisseria gonorrhoeae. In vitro antimicrobial-susceptibility testing (AST) is done to identify the most efficacious antibiotic needed to combat the infection in that particular individual. The objective of this study was to evaluate whether Kirby–Bauer (KB) disk-diffusion tests can detect N. gonorrhoeae isolates that have decreased susceptibility to ceftriaxone and cefixime for appropriate clinical management.

Methods

A total of 1,633 consecutive clinical isolates of N. gonorrhoeae were collected from January 1, 2013 to December 31, 2017 from seven dermatology clinics located in five provinces in China. Consistency between KB disk-diffusion tests and the agar-dilution method, as well as sensitivity of the KB test for detecting N. gonorrhoeae isolates with decreased susceptibility to ceftriaxone and cefixime, were determined using 1,306 clinical isolates that had been recovered to complete agar-dilution AST.

Results

The prevalence of isolates with decreased susceptibility to ceftriaxone and cefixime was 12.1% (198 of 1,633) and 12.7% (208 of 1,633), respectively, using KB disk-diffusion tests. The prevalence of isolates with decreased susceptibility was 9.9% (129 of 1,306) for ceftriaxone and 9.9% (129 of 1,305) for cefixime using agar-dilution AST. The categorical agreement of these two methods was 80.9% for both ceftriaxone and cefixime. Compared to agar-dilution AST, the sensitivity of the KB test for detecting N. gonorrhoeae isolates with decreased susceptibility was 22.5% (29 of 129) for ceftriaxone and 29.5% (38 of 129) for cefixime, and its specificity 87.3% (1,028 of 1,177) for ceftriaxone and 86.7% (1,018 of 1,176) for cefixime.

Conclusion

Although KB tests are easy to carry out in clinical practice, their ability to detect cephalosporin-resistant gonorrhoea strains is limited. This method is not an appropriate selection for screening cephalosporin-resistant gonorrhoea strains in clinical practice in China.

Zoliflodacin: An Oral Spiropyrimidinetrione Antibiotic for the Treatment of Neisseria gonorrheae, Including Multi-Drug-Resistant Isolates

The Centers for Disease Control and the World Health Organization have issued a list of priority pathogens for which there are dwindling therapeutic options, including antibiotic-resistant Neisseria gonorrheae, for which novel oral agents are urgently needed. Zoliflodacin, the first in a new class of antibacterial agents called the spiropyrimidinetriones, is being developed for the treatment of gonorrhea. It has a unique mode of inhibition against bacterial type II topoisomerases with binding sites in bacterial gyrase that are distinct from those of the fluoroquinolones. Zoliflodacin is bactericidal, with a low frequency of resistance and potent antibacterial activity against N. gonorrheae, including multi-drug-resistant strains (MICs ranging from ≤0.002 to 0.25 μg/mL). Although being developed for the treatment of gonorrhea, zoliflodacin also has activity against Gram-positive, fastidious Gram-negative, and atypical pathogens. A hollow-fiber infection model using S. aureus showed that that pharmacokinetic/pharmacodynamic index of fAUC/MIC best correlated with efficacy in in vivo neutropenic thigh models in mice. This data and unbound exposure magnitudes derived from the thigh models were subsequently utilized in a surrogate pathogen approach to establish dose ranges for clinical development with N. gonorrheae. In preclinical studies, a wide safety margin supported progression to phase 1 studies in healthy volunteers, which showed linear pharmacokinetics, good oral bioavailability, and no significant safety findings. In a phase 2 study, zoliflodacin was effective in treating gonococcal urogenital and rectal infections. In partnership with the Global Antibiotic Research Development Program (GARDP), zoliflodacin is currently being studied in a global phase 3 clinical trial. Zoliflodacin represents a promising new oral therapy for drug-resistant infections caused by N. gonorrheae.

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.