Gonococcal Antimicrobial Resistance Research Articles

Local emergence and global evolution of Neisseria gonorrhoeae with high-level resistance to azithromycin.

Antimicrobial resistance in Neisseria gonorrhoeae (Ng) has severely reduced treatment options, including azithromycin (AZM), which had previously been recommended as dual therapy with ceftriaxone. This study characterizes the emergence of high-level resistance to AZM (HLR-AZM) Ng in Baltimore, Maryland, USA, and describes the global evolution of HLR-AZM Ng. Whole genome sequencing (WGS) of 30 Ng isolates with and without HLR-AZM from Baltimore was used to identify clonality and resistance determinants. Publicly available WGS data from global HLR-AZM Ng (n = 286) and the Baltimore HLR-AZM Ng (n = 3) were used to assess the distribution, clonality, and diversity of HLR-AZM Ng. The HLR-AZM Ng isolates from Baltimore identified as multi-locus sequencing typing sequence type (ST) 9363 and likely emerged from circulating strains. ST9363 was the most widely disseminated ST globally represented in eight countries and was associated with sustained transmission events. The number of global HLR-AZM Ng, countries reporting these isolates, and strain diversity increased in the last decade. The majority (89.9%) of global HLR-AZM Ng harbored the A2059G mutation in all four alleles of the 23S rRNA gene, but isolates with two or three A2059G alleles, and alternative HLR-AZM mechanisms were also identified. In conclusion, HLR-AZM in Ng has increased in the last few years, with ST9363 emerging as an important gonococcal lineage globally. The 23S rRNA A2059G mutation is the most common resistance mechanism, but alternative mechanisms are emerging. Continued surveillance of HLR-AZM Ng, especially ST9363, and extensively drug-resistant Ng is warranted.

MOLECULAR SURVEILLANCE OF GONOCOCCAL CIPROFLOXACIN SUSCEPTIBILITY/RESISTANCE IN BULGARIA, 2022-2023

Background: The emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is a significant public health issue, with Euro-GASP conducting surveillance across the EU-EEA. The advent of molecular diagnostics for N. gonorrhoeae may possibly limit the surveillance data because it is dependent on gonococcal culture for phenotypic susceptibility testing. Ideally, molecular diagnostics should combine identification and resistance detection but the complexity of gonococcal molecular genetics of resistance is a major barrier for test development. Currently, resistance prediction in N. gonorrhoeae is accurate only for fluoroquinolones and there are commercial kits available on the market that allow antimicrobial resistance surveillance and individualized treatment. The study examined Bulgaria's gonococcal fluoroquinolone resistance rate for 2022-2023 by molecular methods and compared it with previous years and EU-EEA trends. Methods: The commercial ResistancePlus® GC assay was used to predict ciprofloxacin susceptibility/resistance in 66 Neisseria gonorrhoeae-positive DNA samples from patients, diagnosed in 2022-2023. Results: The identified fluoroquinolone resistance rate in 2022-2023 was 68.2%. The majority of the cases were males in the age group 20-29 (50.8%), the most common mode of transmission was MSM (77%) and 17% of the cases with known HIV status were positive. Conclusion: This study found a higher than before fluoroquinolone resistance rate (68.2%) in Bulgaria, following the trend in Europe. In the EU-EEA, ciprofloxacin resistance increased to 65.9% in 2022. Molecular testing for predicting susceptibility/resistance is suitable for effective antimicrobial resistance surveillance and individualized treatment decisions.

A molecular and phenotypic analysis of the prevalence and patterns of antimicrobial resistance in Neisseria gonorrhoeae isolates from Kwazulu Natal, South Africa

Antimicrobial drug resistance in Neisseria gonorrhoeae has been documented worldwide; however, the situation in Sub-Saharan Africa has received little attention. It is critical to establish diagnostics and extend surveillance to prevent the emergence of illnesses resistant to multiple treatments. Monitoring antimicrobial susceptibility is crucial to gather data that can inform treatment recommendations, resulting in effective therapy, reduced gonorrhea-related complications and transmission, and efficient treatment. Government authorities may set research and preventive objectives, as well as treatment recommendations, using data from the Gonococcal Antimicrobial Surveillance Program (GISP). Local and state health authorities may use GISP data to make decisions about the allocation of STI prevention services and resources, to guide preventive planning, and to disseminate information about the most successful treatment practices. Using molecular and culture approaches, we investigated the occurrence of antibiotic resistance in isolates from KwaZulu Natal, South Africa. The majority of gonococcal isolates (48 %) showed absolute resistance to ciprofloxacin, with penicillin and tetracycline resistance rates of 14 % each. Only one gonococcal isolate tested positive for azithromycin resistance, with a minimum inhibitory concentration (MIC) of 1.5 µg/mL. Ceftriaxone was effective against all gonococcal isolates tested.

Providing adolescent-friendly sexually transmitted infection screening and treatment services.

There are high rates of sexually transmitted infections (STIs) worldwide. Adolescents and young adults (AYA) ages 15-24 years remain one of the populations that is most vulnerable to STIs. The goal of this review is to summarize recent international updates in adolescent STI screening and treatment. Normalizing sexual history taking and STI testing, and advocating for adolescents to receive comprehensive sexuality education improves stigma surrounding sexual health. The global rise in syphilis is pervasive and includes high rates of infection among AYA and women of reproductive age - universal screening may be indicated depending on local epidemiology. Gonococcal antimicrobial resistance remains a significant public health concern worldwide, thus judicious use of antimicrobials and reporting cases of resistance is crucial. Sexual health services are increasingly using virtual platforms, which may be an effective strategy for STI testing and treatment among AYA. Specific areas of focus to address the STI epidemic among AYA include reducing stigma surrounding sexual health, screening, and treatment of STIs, especially with the global rise in syphilis and high rates of gonorrhea resistance, in addition to increased use of telehealth services as effective education and intervention strategies.

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

MDR and XDR Neisseria gonorrhoeae strains remain major public health concerns internationally, and quality-assured global gonococcal antimicrobial resistance (AMR) surveillance is imperative. The WHO global Gonococcal Antimicrobial Surveillance Programme (GASP) and WHO Enhanced GASP (EGASP), including metadata and WGS, are expanding internationally. We present the phenotypic, genetic and reference genome characteristics of the 2024 WHO gonococcal reference strains (n = 15) for quality assurance worldwide. All superseded WHO gonococcal reference strains (n = 14) were identically characterized. The 2024 WHO reference strains include 11 of the 2016 WHO reference strains, which were further characterized, and four novel strains. The superseded WHO reference strains include 11 WHO reference strains previously unpublished. All strains were characterized phenotypically and genomically (single-molecule PacBio or Oxford Nanopore and Illumina sequencing). The 2024 WHO reference strains represent all available susceptible and resistant phenotypes and genotypes for antimicrobials currently and previously used (n = 22), or considered for future use (n = 3) in gonorrhoea treatment. The novel WHO strains include internationally spreading ceftriaxone resistance, ceftriaxone resistance due to new penA mutations, ceftriaxone plus high-level azithromycin resistance and azithromycin resistance due to mosaic MtrRCDE efflux pump. AMR, serogroup, prolyliminopeptidase, genetic AMR determinants, plasmid types, molecular epidemiological types and reference genome characteristics are presented for all strains. The 2024 WHO gonococcal reference strains are recommended for internal and external quality assurance in laboratory examinations, especially in the WHO GASP, EGASP and other GASPs, but also in phenotypic and molecular diagnostics, AMR prediction, pharmacodynamics, epidemiology, research and as complete reference genomes in WGS analysis.

Australian Gonococcal Surveillance Programme, 1 October to 31 December 2023

The Australian National Neisseria Network (NNN) comprises reference laboratories in each state and territory that report data on antimicrobial susceptibility testing to an agreed group of antimicrobial agents for the Australian Gonococcal Surveillance Programme (AGSP). The AGSP data are presented quarterly in tabulated form, as well as in the AGSP annual report. This report presents national gonococcal antimicrobial resistance surveillance data from 1 October to 31 December 2023

Australian Gonococcal Surveillance Programme, 1 October to 31 December 2023.

The Australian National Neisseria Network (NNN) comprises reference laboratories in each state and territory that report data on antimicrobial susceptibility testing to an agreed group of antimicrobial agents for the Australian Gonococcal Surveillance Programme (AGSP). The AGSP data are presented quarterly in tabulated form, as well as in the AGSP annual report. This report presents national gonococcal antimicrobial resistance surveillance data from 1 October to 31 December 2023.

Antimicrobial-resistant Neisseria gonorrhoeae in Europe in 2020 compared with in 2013 and 2018: a retrospective genomic surveillance study

Regular quality-assured whole-genome sequencing linked to antimicrobial resistance (AMR) and patient metadata is imperative to elucidate the shifting gonorrhoea epidemiology, both nationally and internationally. We aimed to examine the gonococcal population in the European Economic Area (EEA) in 2020, elucidate emerging and disappearing gonococcal lineages associated with AMR and patient metadata, compare with 2013 and 2018 whole-genome sequencing data, and explain changes in gonococcal AMR and gonorrhoea epidemiology. In this retrospective genomic surveillance study, we analysed consecutive gonococcal isolates that were collected in EEA countries through the European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) in 2020, and made comparisons with Euro-GASP data from 2013 and 2018. All isolates had linked AMR data (based on minimum inhibitory concentration determination) and patient metadata. We performed whole-genome sequencing and molecular typing and AMR determinants were derived from quality-checked whole-genome sequencing data. Links between genomic lineages, AMR, and patient metadata were examined. 1932 gonococcal isolates collected in 2020 in 21 EEA countries were included. The majority (81·2%, 147 of 181 isolates) of azithromycin resistance (present in 9·4%, 181 of 1932) was explained by the continued expansion of the Neisseria gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) clonal complexes (CCs) 63, 168, and 213 (with mtrD/mtrR promoter mosaic 2) and the novel NG-STAR CC1031 (semi-mosaic mtrD variant 13), associated with men who have sex with men and anorectal or oropharyngeal infections. The declining cefixime resistance (0·5%, nine of 1932) and negligible ceftriaxone resistance (0·1%, one of 1932) was largely because of the progressive disappearance of NG-STAR CC90 (with mosaic penA allele), which was predominant in 2013. No known resistance determinants for novel antimicrobials (zoliflodacin, gepotidacin, and lefamulin) were found. Azithromycin-resistant clones, mainly with mtrD mosaic or semi-mosaic variants, appear to be stabilising at a relatively high level in the EEA. This mostly low-level azithromycin resistance might threaten the recommended ceftriaxone-azithromycin therapy, but the negligible ceftriaxone resistance is encouraging. The decreased genomic population diversity and increased clonality could be explained in part by the COVID-19 pandemic resulting in lower importation of novel strains into Europe. European Centre for Disease Prevention and Control and Örebro University Hospital.

Australian Gonococcal Surveillance Programme, 1 April to 30 June 2023.

The Australian National Neisseria Network (NNN) comprises reference laboratories in each state and territory that report data on antimicrobial susceptibility testing to an agreed group of antimicrobial agents for the Australian Gonococcal Surveillance Programme (AGSP). The AGSP data are presented quarterly in tabulated form, as well as in the AGSP annual report. This report presents national gonococcal antimicrobial resistance surveillance data from 1 April to 30 June 2023.

Australian Gonococcal Surveillance Programme, 1 July to 30 September 2023.

The Australian National Neisseria Network (NNN) comprises reference laboratories in each state and territory that report data on antimicrobial susceptibility testing to an agreed group of antimicrobial agents for the Australian Gonococcal Surveillance Programme (AGSP). The AGSP data are presented quarterly in tabulated form, as well as in the AGSP annual report. This report presents national gonococcal antimicrobial resistance surveillance data from 1 July to 30 September 2023.

Australian Gonococcal Surveillance Programme, 1 January to 31 March 2023.

The Australian National Neisseria Network (NNN) comprises reference laboratories in each state and territory that report data on antimicrobial susceptibility testing to an agreed group of antimicrobial agents for the Australian Gonococcal Surveillance Programme (AGSP). The AGSP data are presented quarterly in tabulated form, as well as in the AGSP annual report. This report presents national gonococcal antimicrobial resistance surveillance data from 1 January to 31 March 2023.

Ceftriaxone-Resistant Gonorrhea - China, 2022.

Gonorrhea is a widespread sexually transmitted infection; in 2022, China reported 96,313 cases of gonorrhea, making it the fourth most common notifiable infectious disease in the country after viral hepatitis, pulmonary tuberculosis, and syphilis. The rise in prevalence in antimicrobial-resistant strains, particularly the international spread of ceftriaxone-resistant clones, poses a formidable challenge to gonorrhea control. The China Gonococcal Resistance Surveillance Program (China-GRSP), established in 1987 and covering 19 of 34 provincial-level administrative units, continuously monitors gonococcal antimicrobial resistance. In 2022, 13 China-GRSP sentinel sites collected 2,804 gonococcal isolates, representing 2.9% of all cases reported in China, and 4.1% of cases reported in the 13 participating provinces. The prevalence of Neisseria gonorrhoeae resistance to ceftriaxone was 8.1%, approximately three times the 2017 rate of 2.9%; five provinces reported >10% ceftriaxone resistance. Resistance prevalences to cefixime, azithromycin, tetracycline, penicillin, and ciprofloxacin were 16.0%, 16.9%, 77.1%, 77.8%, and 97.6%, respectively. Only one case of spectinomycin resistance was reported. These data highlight a substantial increase in ceftriaxone resistance from 2017 to 2022. Effective diagnosis and treatment and appropriate management of sex partners are essential to protect the health of infected persons and prevent ongoing transmission of gonorrhea, including transmission of resistant strains. Identifying reasons for the spread of ceftriaxone-resistant N. gonorrhoeae in China could guide strategies, such as antibiotic stewardship, to mitigate the rising resistance rate and curb the spread of resistant strains.

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

Antimicrobial resistance in Neisseria gonorrhoeae is a global public health concern. Tetracycline resistance (TetR) increased from 39.4% to 75.2% between 2016 and 2021 in N. gonorrhoeae isolates collected through national surveillance in England, despite the absence of use of tetracyclines for the treatment of gonorrhoea. We investigated whether there was correlation between bacterial sexually transmitted infection (STI) tests performed and treatment with antimicrobials, with increased TetR in N. gonorrhoeae. We examined correlations between bacterial STI tests, antimicrobial treatment and TetR in N. gonorrhoeae, using national surveillance data from three large sexual health services (SHS) in London during 2016-20. Doxycycline prescribing data and antibiograms of a non-STI pathogen from distinct patient groups (sexual health, obstetric and paediatric), at a large London hospital, were analysed to identify if doxycycline use in SHS was associated with resistance in a non-STI organism. A substantial increase in TetR was observed, particularly in isolates from gay, bisexual and other MSM (GBMSM). Strong positive correlations were observed exclusively in GBMSM between N. gonorrhoeae TetR and both bacterial STI tests (r = 0.97, P = 0.01) and antimicrobial treatment (r = 0.87, P = 0.05). Doxycycline prescribing increased dramatically during the study period in SHS. Prevalence of TetR in Staphylococcus aureus was higher in isolates sourced from SHS attendees than those from other settings. Frequent screening of GBMSM at higher risk of STIs, such as those on pre-exposure prophylaxis (PrEP) leading to/and increased use of doxycycline for the treatment of diagnosed infections, may account for the increase in TetR in N. gonorrhoeae.

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

Regular quality-assured WGS with antimicrobial resistance (AMR) and epidemiological data of patients is imperative to elucidate the shifting gonorrhoea epidemiology, nationally and internationally. We describe the dynamics of the gonococcal population in 11 cities in Brazil between 2017 and 2020 and elucidate emerging and disappearing gonococcal lineages associated with AMR, compare to Brazilian WGS and AMR data from 2015 to 2016, and explain recent changes in gonococcal AMR and gonorrhoea epidemiology. WGS was performed using Illumina NextSeq 550 and genomes of 623 gonococcal isolates were used for downstream analysis. Molecular typing and AMR determinants were obtained and links between genomic lineages and AMR (determined by agar dilution/Etest) examined. Azithromycin resistance (15.6%, 97/623) had substantially increased and was mainly explained by clonal expansions of strains with 23S rRNA C2611T (mostly NG-STAR CC124) and mtr mosaics (mostly NG-STAR CC63, MLST ST9363). Resistance to ceftriaxone and cefixime remained at the same levels as in 2015-16, i.e. at 0% and 0.2% (1/623), respectively. Regarding novel gonorrhoea treatments, no known zoliflodacin-resistance gyrB mutations or gepotidacin-resistance gyrA mutations were found. Genomic lineages and sublineages showed a phylogenomic shift from sublineage A5 to sublineages A1-A4, while isolates within lineage B remained diverse in Brazil. Azithromycin resistance, mainly caused by 23S rRNA C2611T and mtrD mosaics/semi-mosaics, had substantially increased in Brazil. This mostly low-level azithromycin resistance may threaten the recommended ceftriaxone-azithromycin therapy, but the lack of ceftriaxone resistance is encouraging. Enhanced gonococcal AMR surveillance, including WGS, is imperative in Brazil and other Latin American and Caribbean countries.

Pharmacodynamic evaluation of ceftriaxone single-dose therapy (0.125-1 g) to eradicate ceftriaxone-susceptible and ceftriaxone-resistant Neisseria gonorrhoeae strains in a hollow fibre infection model for gonorrhoea.

Antimicrobial resistance in Neisseria gonorrhoeae is threatening the gonorrhoea treatment, and optimizations of the current ceftriaxone-treatment regimens are crucial. We evaluated the pharmacodynamics of ceftriaxone single-dose therapy (0.125-1 g) against ceftriaxone-susceptible and ceftriaxone-resistant gonococcal strains, based on EUCAST ceftriaxone-resistance breakpoint (MIC > 0.125 mg/L), in our hollow fibre infection model (HFIM) for gonorrhoea. Gonococcal strains examined were WHO F (ceftriaxone-susceptible, MIC < 0.002 mg/L), R (ceftriaxone-resistant, MIC = 0.5 mg/L), Z (ceftriaxone-resistant, MIC = 0.5 mg/L) and X (ceftriaxone-resistant, MIC = 2 mg/L). Dose-range HFIM 7 day experiments simulating ceftriaxone 0.125-1 g single-dose intramuscular regimens were conducted. Ceftriaxone 0.125-1 g single-dose treatments rapidly eradicated WHO F (wild-type ceftriaxone MIC). Ceftriaxone 0.5 and 1 g treatments, based on ceftriaxone human plasma pharmacokinetic parameters, eradicated most ceftriaxone-resistant gonococcal strains (WHO R and Z), but ceftriaxone 0.5 g failed to eradicate WHO X (high-level ceftriaxone resistance). When simulating oropharyngeal gonorrhoea, ceftriaxone 0.5 g failed to eradicate all the ceftriaxone-resistant strains, while ceftriaxone 1 g eradicated WHO R and Z (low-level ceftriaxone resistance) but failed to eradicate WHO X (high-level ceftriaxone resistance). No ceftriaxone-resistant mutants were selected using any ceftriaxone treatments. Ceftriaxone 1 g single-dose intramuscularly cure most of the anogenital and oropharyngeal gonorrhoea cases caused by the currently internationally spreading ceftriaxone-resistant gonococcal strains, which should be further confirmed clinically. A ceftriaxone 1 g dose (±azithromycin 2 g) should be recommended for first-line empiric gonorrhoea treatment. This will buy countries some time until novel antimicrobials are licensed. Using ceftriaxone 1 g gonorrhoea treatment, the EUCAST ceftriaxone-resistance breakpoint is too low.

Molecular epidemiological and antimicrobial-resistant mechanisms analysis of prolonged Neisseria gonorrhoeae collection between 1971 and 2005 in Japan.

As antimicrobial-resistant (AMR) Neisseria gonorrhoeae strains have emerged, humans have adjusted the antimicrobials used to treat infections. We identified shifts in the N. gonorrhoeae population and the determinants of AMR strains isolated during the recurring emergence of resistant strains and changes in antimicrobial therapies. We examined 243 N. gonorrhoeae strains corrected at the Kanagawa Prefectural Institute of Public Health, Kanagawa, Japan, these isolated in 1971-2005. We performed multilocus sequence typing and AMR determinants (penA, mtrR, porB, ponA, 23S rRNA, gyrA and parC) mainly using high-throughput genotyping methods together with draft whole-genome sequencing on the MiSeq (Illumina) platform. All 243 strains were divided into 83 STs. ST1901 (n = 17) was predominant and first identified after 2001. Forty-two STs were isolated in the 1970s, 34 in the 1980s, 22 in the 1990s and 13 in the 2000s, indicating a decline in ST diversity over these decades. Among the 29 strains isolated after 2001, 28 were highly resistant to ciprofloxacin (MIC ≥ 8 mg/L) with two or more amino-acid substitutions in quinolone-resistance-determining regions. Seven strains belonging to ST7363 (n = 3), ST1596 (n = 3) and ST1901 (n = 1) were not susceptible to cefixime, and six strains carried penA alleles with mosaic-like penicillin-binding protein 2 (PBP2; penA 10.001 and 10.016) or PBP2 substitutions A501V and A517G. We observed a significant reduction in the diversity of N. gonorrhoeae over 35 years in Japan. Since 2001, ST1901, which is resistant to ciprofloxacin, has superseded previous strains, becoming the predominant ST population.

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

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

Detection of antimicrobial resistance in

Antimicrobial resistance in Neisseria gonorrhoeae compromises gonorrhoea treatment and rapid antimicrobial susceptibility testing (AST) would be valuable. We have developed a rapid and accurate flow cytometry method (FCM) for AST of gonococci. The 2016 WHO gonococcal reference strains, and WHO Q, R and S (n = 17) were tested against seven clinically relevant antibiotics (ceftriaxone, cefixime, azithromycin, spectinomycin, ciprofloxacin, tetracycline and gentamicin). After 4.5 h incubation of inoculated broth, the fluorescent dye Syto™ 9 was added, followed by FCM analysis. After gating, the relative remaining population of gonococci, compared with unexposed growth control samples, was plotted against antimicrobial concentration, followed by non-linear curve regression analysis. Furthermore, the response at one single concentration/tested antibiotic was evaluated with the intention to use as a screening test for detection of resistant gonococci. A dose-dependent response was seen in susceptible isolates for all tested antimicrobials. There was a clear separation between susceptible/WT and resistant/non-WT isolates for ceftriaxone, cefixime, spectinomycin, ciprofloxacin and tetracycline. In contrast, for azithromycin, only high-level-resistant isolates were distinguished, while resistant isolates with MICs of 4 mg/L were indistinguishable from WT (MIC ≤ 1 mg/L) isolates. For gentamicin, all tested 17 isolates were WT and FCM analysis resulted in uniform dose-response curves. Using a single antibiotic concentration and a 50% remaining cell population cut-off, the overall sensitivity and specificity for resistance detection were 93% and 99%, respectively. By providing results in <5 h for gonococcal isolates, FCM-based AST can become a rapid screening method for antimicrobial resistance or antimicrobial susceptibility in gonococci.

Antimicrobial resistance and molecular characteristics of Neisseria gonorrhoea isolates in Ghana.

Gonorrhoea is a disease associated with humans and caused by Neisseria gonorrhoea. N. gonorrhoea's ability to evolve and evade various treatment regimens can lead to untreatable gonorrhoea. In the absence of a viable vaccine and a national database on the antimicrobial resistance (AMR) and molecular characteristics of N. gonorrhoea, and with reliance on a syndromic management regime, continuous national antimicrobial resistance surveillance and molecular characterization of N. gonorrhoea remain imperative. Only two gonococcal studies have described N. gonorrhoea's molecular characteristics linked to AMR in Ghana. Secondary N. gonorrhoea isolates (n=4) were collected from two metropolises in Ghana: Tamale in the northern sector (n=1) and Accra in the southern sector (n=3). The isolates were confirmed and characterized using polymerase chain reaction (PCR) targeting the porB and tbpB genes, and the disc diffusion method was used to evaluate AMR. N. gonorrhoea multi-antigen sequence typing (NG-MAST) and porin B (porB) gene sequence analyses were employed to reveal the molecular epidemiology and evolutionary trajectory, respectively. All four isolates showed resistance to at least four of the tested antibiotics. One isolate showed resistance to all seven antibiotics, i.e. ceftriaxone, azithromycin, ciprofloxacin, tetracycline, erythromycin, togamycin and penicillin. NG-MAST typing revealed isolate S3 (MZ313864) as ST211. The locus of S2 (MZ313863) (transferrin-binding protein B; tbpB) was identified as tbpB1844, and its porB locus, as porB6412, with only 4 closely related variants but with 15 nucleotide differences. However, its sequence type does not exist. The porB analysis identified isolate S3 (MZ313864) to be found globally, while S2 (MZ313863) is unique to this study. Despite the small number of isolates tested, this study recorded multidrug resistance and previously unknown gonococcal variants based on porB gene. Additionally, the molecular typing schemes revealed a disparity between NG-MAST and the National Center for Biotechnology Information (NCBI) platforms. There is a need for continuous gonococcal AMR and molecular surveillance in Ghana to contribute to the global efforts to describe circulating strains and support proper application of the syndromic management regime to gonorrhoea.

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

While ceftriaxone resistance remains scarce in Switzerland, global Neisseria gonorrhoeae (NG) antimicrobial resistance poses an urgent threat. This study describes clinical characteristics in MSM (men who have sex with men) diagnosed with NG infection and analyses NG resistance by phenotypic and genotypic means. Data of MSM enrolled in three clinical cohorts with a positive polymerase chain reaction test (PCR) for NG were analysed between January 2019 and December 2021 and linked with antibiotic susceptibility testing. Bacterial isolates were subjected to whole genome sequencing (WGS). Of 142 participants, 141 (99%) were MSM and 118 (84%) living with HIV. Participants were treated with ceftriaxone (N = 79), azithromycin (N = 2), or a combination of both (N = 61). No clinical or microbiological failures were observed. From 182 positive PCR samples taken, 23 were available for detailed analysis. Based on minimal inhibitory concentrations (MICs), all isolates were susceptible to ceftriaxone, gentamicin, cefixime, cefpodoxime, ertapenem, zoliflodacin, and spectinomycin. Resistance to azithromycin, tetracyclines and ciprofloxacin was observed in 10 (43%), 23 (100%) and 11 (48%) of the cases, respectively. Analysis of WGS data revealed combinations of resistance determinants that matched with the corresponding phenotypic resistance pattern of each isolate. Among the MSM diagnosed with NG mainly acquired in Switzerland, ceftriaxone MICs were low for a subset of bacterial isolates studied and no treatment failures were observed. For azithromycin, high occurrences of in vitro resistance were found. Gentamicin, cefixime, cefpodoxime, ertapenem, spectinomycin, and zoliflodacin displayed excellent in vitro activity against the 23 isolates underscoring their potential as alternative agents to ceftriaxone.