Azithromycin-resistant Neisseria Gonorrhoeae Research Articles

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

In South Africa, Neisseria gonorrhoeae , which is the predominant cause of male urethritis, is treated syndromically using dual ceftriaxone and azithromycin therapy. We determined antimicrobial susceptibilities of N. gonorrhoeae isolates from urethral discharge specimens, and genetically characterised those with elevated minimum inhibitory concentrations (MICs) for first-line antimicrobials. Routine antimicrobial susceptibility testing (AST) of N. gonorrhoeae isolates included E-test for ceftriaxone, cefixime and gentamicin and agar dilution for azithromycin and spectinomycin. Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) was performed for isolates with elevated MICs to identify antimicrobial resistance (AMR) determinants, and Neisseria gonorrhoeae Multi-Antigen Sequence Typing (NG-MAST) was used to determine strain relatedness. N. gonorrhoeae was cultured from urethral discharge swab specimens obtained from 196 of 238 (82.4%) men presenting to a primary healthcare facility in Johannesburg in 2021. All viable isolates were susceptible to extended-spectrum cephalosporins. Four isolates had high azithromycin MICs ranging from 32mg/L to >256mg/L and grouped into two novel NG-MAST and NG-STAR groups. Two isolates from Group 1 (NG-MAST ST20366, NG-STAR ST4322) contained mutated mtrR (G45D) and 23S rRNA (A2059G) alleles, while the two isolates from Group 2 (NG-MAST ST20367, NG-STAR ST4323) had different mutations in mtrR (A39T) and 23S rRNA (C2611T). We report the first cases of high-level azithromycin resistance in N. gonorrhoeae from South Africa. Continued AMR surveillance is critical to detect increasing azithromycin resistance prevalence in N. gonorrhoeae , which may justify future modifications to the STI syndromic management guidelines.

Genetic characteristics of azithromycin-resistant Neisseria gonorrhoeae collected in Hyogo, Japan during 2015-2019.

Introduction. Azithromycin (AZM) is a therapeutic drug for sexually transmitted infections and is used for Neisseria gonorrhoeae when first- and second-line drugs are not available. Recently, the susceptibility of N. gonorrhoeae against AZM has been decreasing worldwide.Hypothesis/Gap Statement. Azithromycin-resistance (AZM-R) rates among N. gonorrhoeae in Japan are increasing, and the gene mutations and epidemiological characteristics of AZM-R in N. gonorrhoeae have not been fully investigated.Aim. We determined the susceptibility to AZM and its correlation with genetic characteristics of N. gonorrhoeae.Methodology. We investigated the susceptibility to AZM and genetic characteristics of N. gonorrhoeae. Mutations in domain V of the 23S rRNA gene and mtrR were examined in 93 isolates, including 13 AZM-R isolates. Spread and clonality were examined using sequence types (STs) of multi-antigen sequence typing for N. gonorrhoeae (NG-MAST), and whole genome analysis (WGA) to identify single nucleotide polymorphisms.Results. The number of AZM-R isolates increased gradually from 2015 to 2019 in Hyogo (P=0.008). C2599T mutations in 23S rRNA significantly increased in AZM-R isolates (P<0.001). NG-MAST ST4207 and ST6762 were frequently detected in AZM-R isolates, and they had higher MICs to AZM from 6 to 24 µg/ml. The phylogenic tree-based WGA showed that all isolates with ST4207 were contained in the same clade, and isolates with ST6762 were divided into two clades, AZM-S isolates and AZM-R isolates, which were different from the cluster containing ST1407.Conclusion. Our study showed yearly increases in AZM-R rates in N. gonorrhoeae. NG-MAST ST4207 and ST6762 were not detected in our previous study in 2015 and were frequently identified in isolates with higher MICs to AZM. WGA confirmed that isolates with these STs are closely related to each other. Continued surveillance is needed to detect the emergence and confirm the spread of NG-MAST ST4207 and ST6762.

Just Google it! Impact of media coverage of an outbreak of high-level azithromycin-resistant Neisseria gonorrhoeae on online searches, and attendances, testing and diagnoses at sexual health clinics in England between 2015 and 2016: an interrupted time series analysis using surveillance data

ObjectivesTo determine if media coverage of an outbreak of high-level azithromycin-resistant Neisseria gonorrhoeae (HL-AziR) impacted online search interest or was temporally associated with health-seeking behaviours in several English cities.MethodsA descriptive...

Genetic relatedness of ceftriaxone-resistant and high-level azithromycin resistant Neisseria gonorrhoeae cases, United Kingdom and Australia, February to April 2018.

Between February and April 2018, three ceftriaxone-resistant and high-level azithromycin-resistant Neisseria gonorrhoeae cases were identified; one in the United Kingdom and two in Australia. Whole genome sequencing was used to show that the isolates from these cases belong to a single gonococcal clone, which we name the A2543 clone.

Evidence for Clonally Associated Increasing Rates of Azithromycin Resistant Neisseria gonorrhoeae in Rio de Janeiro, Brazil.

Azithromycin is one of the drugs used in the combined therapy for syndromic treatment of gonorrhoea in many countries, including Brazil. Our research group, which receives isolates from clinical laboratories since 2006, has detected, after 2016, a tendency of rising rates of azithromycin resistance, with isolates showing higher minimal inhibitory concentrations (MICs) than those previously reported in this country. In this study, we report the susceptibility to azithromycin of 93 N. gonorrhoeae isolates obtained between 2014 and 2017. Strains with MIC ≥2 μg/mL were characterized according to azithromycin resistance mechanisms and strain typing. Results indicate that azithromycin resistance has emerged in all these years in unrelated MLST-STs, but after 2016 a clonal complex connected with ST1901 has been more frequently detected, grouping isolates with MIC varying from 2 to 64 μg/mL, with DelA mutations at the mtrR promoter region associated or not with mutations at rrl alleles. High rates of azithromycin resistance may compromise the use of this drug in the combined therapy with ceftriaxone. Inclusion of Rio de Janeiro in the Brazilian gonococcal surveillance program is important to evaluate if this data indicates an epidemiological phenomenon in the country.

Persistence of an outbreak of gonorrhoea with high-level resistance to azithromycin in England, November 2014‒May 2018.

Between November 2014 and May 2018, 118 laboratory-confirmed cases of high-level azithromycin resistant Neisseria gonorrhoeae were identified in England. Cases emerged among heterosexuals in Leeds but spread across England and into sexual networks of men who have sex with men as the outbreak progressed. The few epidemiological links identified indicate substantial under-diagnosis of cases and this, along with the upturn in cases in 2017, highlights the difficulties in controlling the outbreak.

Sustained transmission of high-level azithromycin-resistant Neisseria gonorrhoeae in England: an observational study

Between Nov 3, 2014, and Feb 24, 2017, 70 cases of high-level azithromycin-resistant (HL-AziR; minimum inhibitory concentration [MIC] ≥256 mg/L) Neisseria gonorrhoeae were reported from across England. Whole-genome sequencing was done to investigate this outbreak to determine whether the ongoing outbreak represented clonal spread of an HL-AziR N gonorrhoeae strain identified in Leeds. We also wanted to elucidate the molecular mechanisms of azithromycin resistance in N gonorrhoeae in the UK. In this observational study, whole-genome sequencing was done on the HL-AziR N gonorrhoeae isolates from England. As comparators, 110 isolates from the UK and Ireland with a range of azithromycin MICs were also sequenced, including eight isolates from Scotland with azithromycin MICs ranging from 0·12 mg/L to 1·00 mg/L that were N gonorrhoeae multi-antigen sequence type 9768 (ST9768), which was the sequence type initially responsible for the outbreak. The presence of mutations or genes associated with azithromycin resistance was also investigated. 37 of the 60 HL-AziR isolates from England belonged to ST9768, and were genetically similar (mean 4·3 single-nucleotide polymorphisms). A 2059A→G mutation was detected in three or all four alleles of the 23S rRNA gene. Five susceptible ST9768 isolates had one mutated 23S rRNA allele and one low-level resistant ST9768 isolate had two mutated alleles. Sustained transmission of a successful HL-AziR clone was seen across England. Mutation 2059A→G was found in isolates with lower azithromycin MICs. Azithromycin exposure might have provided the selection pressure for one or two mutated copies of the 23S rRNA gene to recombine with wild-type copies, leading to three or four mutated copies and the HL-AziR phenotype. HL-AziR could emerge in isolates with low azithromycin MICs and eliminate the effectiveness of azithromycin as part of dual therapy for the treatment of gonorrhoea. Public Health England.

Is previous azithromycin treatment associated with azithromycin resistance in Neisseria gonorrhoeae? A cross-sectional study using national surveillance data in England

ObjectivesIt has been suggested that treatment of STIs with azithromycin may facilitate development of azithromycin resistance in Neisseria gonorrhoeae (NG) by exposing the organism to suboptimal doses. We investigated whether...

Whole genome sequencing to characterise azithromycin resistant Neisseria gonorrhoeae from New South Wales in 2017

Gonococcal antimicrobial resistance is a global concern. Treatment failure is reported for every class of clinically assessed antimicrobial agent. The World Health Organization (WHO) recommends dual therapy (azithromycin and ceftriaxone) to forestall ceftriaxone resistance, although azithromycin resistance is now increasing. In 2016, a major outbreak of azithromycin resistant Neisseria gonorrhoeae occurred in South Australia, with secondary outbreaks detected in other states including New South Wales (NSW).

Azithromycin-resistant Neisseria gonorrhoeae spreading amongst men who have sex with men (MSM) and heterosexuals in New South Wales, Australia, 2017.

To identify the genetic basis of resistance as well as to better understand the epidemiology of a recent surge in azithromycin-resistant Neisseria gonorrhoeae in New South Wales, Australia. Azithromycin-resistant N. gonorrhoeae isolates (n = 118) collected from 107 males, 10 females and 1 transsexual between January and July 2017 were genotyped using a previously described iPLEX method. The results were compared with phenotypic resistance profiles and available patient data. The iPLEX results revealed 10 different N. gonorrhoeae genotypes (designated AZI-G1 to AZI-G10) of which three were responsible for the majority of infections; AZI-G10 (74.6%, 88 isolates; 87 males and 1 transsexual), AZI-G4 (11.0%, 13 isolates; 7 males and 6 females) and AZI-G7 (6.8%, 8 isolates; 7 males and 1 female). The observed resistance was attributable to one of two different azithromycin resistance mechanisms; the 23S rRNA C2611T mutation was identified in 24% of isolates, whereas the majority of resistance (76%) was associated with a meningococcal-type mtrR variant. Additionally, one isolate was found to harbour both the 23S rRNA C2611T mutation and a type XXXIV mosaic penA sequence associated with cephalosporin resistance. These data indicate outbreaks of azithromycin-resistant gonococci amongst networks of MSM and heterosexuals in New South Wales. The results also provide further evidence that azithromycin may soon be an ineffective treatment option for gonococcal infection and highlight the urgent need to explore alternative therapies.

Fourteen Draft Genome Sequences for the First Reported Cases of Azithromycin-Resistant Neisseria gonorrhoeae in Ireland.

ABSTRACTHere, we report the draft genome assemblies of 14 azithromycin-resistant Neisseria gonorrhoeae clinical isolates, representing the first such strains identified in Ireland. Among these isolates are the first reported highly resistant strains (MIC >256 mg/liter), which both belonged to the ST1580 sequence type.

Antibiotic resistant mechanism and epidemiological characteristics of azithromycin-resistant Neisseria gonorrhoeae strains in Shenzhen

Objective To investigate the prevalence, molecular mechanism and genetic characteristics of azithromycin-resistant Neisseria gonorrhoeae (N.gonorrhoeae) strains isolated in Shenzhen. Methods N. gonorrhoeae strains were collected in Shenzhen from 2011 to 2015. Agar dilution method and E-test were used to detect the minimum inhibitory concentrations (MIC) of these strains to azithromycin. All azithromycin-resistant (AZM-R) strains (MIC≥2 μg/ml) and some azithromycin-sensitive strains (MIC≤0.25 μg/ml) which were randomly selected as the control group were screened for mutations in 23S rRNA, mtrR and erm genes and genotyped by using N. gonorrhoeae multi-antigen sequence typing (NG-MAST). Results A total of 788 N. gonorrhoeae strains were collected, 148 (18.8%) of which were AZM-R strains (MIC≥1 μg/ml). Eighteen out of 21 high-level AZM-R (AZM-HLR) strains had A2143G mutations in the four copies of the 23S rRNA gene. Twelve out of 29 middle-level AZM-R (AZ-MLR) strains had missense mutations, among which C2611T mutations in the four copies of the 23S rRNA were detected in 10 strains. Incidence of G45D/Y105H mutation in AZM-HLR strains was higher than that in AZM-MLR (χ2=12.702, P=0.000) or AZ-S (χ2=4.462, P=0.035) strains according to the analysis of the promoter and coding region of mtrR gene. PCR analysis revealed that only one strain carried ermB gene (MIC=2 μg/ml). The 788 N. gonorrhoeae strains were typed into 81 sequence types (STs) by NG-MAST, most of which were represented by one strain only. STs of ST3356 and ST1866 that were identified in the AZ-R strains in the current study had been noted in a previous report of emerging AZM-R N. gonorrhoeae strains in Nanjing, Chongqing and Guangzhou. Neighbor-joining (NJ) phylogenetic tree showed that the resistant strains did not form a separate cluster. Conclusion Currently, it is not suitable to use azithromycin as a monotherapy for gonorrhea in Shenzhen. Mutations of A2059G and C2611T in 23S rRNA of N. gonorrhoeae were respectively responsible for high-level and middle-level resistance to azithromycin. Repeated emergence of ST1866 and ST3356 will help us monitor and analyze the epidemiological characteristics of N. gonorrhoeae strains resistant to azithromycin in Shenzhen. Key words: Neisseria gonorrhoeae; Azithromycin; Resistance gene; NG-MAST

WGS analysis and molecular resistance mechanisms of azithromycin-resistant (MIC >2 mg/L) Neisseria gonorrhoeae isolates in Europe from 2009 to 2014.

To elucidate the genome-based epidemiology and phylogenomics of azithromycin-resistant (MIC >2 mg/L) Neisseria gonorrhoeae strains collected in 2009-14 in Europe and clarify the azithromycin resistance mechanisms. Seventy-five azithromycin-resistant (MIC 4 to >256 mg/L) N. gonorrhoeae isolates collected in 17 European countries during 2009-14 were examined using antimicrobial susceptibility testing and WGS. Thirty-six N. gonorrhoeae multi-antigen sequence typing STs and five phylogenomic clades, including 4-22 isolates from several countries per clade, were identified. The azithromycin target mutation A2059G (Escherichia coli numbering) was found in all four alleles of the 23S rRNA gene in all isolates with high-level azithromycin resistance (n = 4; MIC ≥256 mg/L). The C2611T mutation was identified in two to four alleles of the 23S rRNA gene in the remaining 71 isolates. Mutations in mtrR and its promoter were identified in 43 isolates, comprising isolates within the whole azithromycin MIC range. No mutations associated with azithromycin resistance were found in the rplD gene or the rplV gene and none of the macrolide resistance-associated genes [mef(A/E), ere(A), ere(B), erm(A), erm(B), erm(C) and erm(F)] were identified in any isolate. Clonal spread of relatively few N. gonorrhoeae strains accounts for the majority of the azithromycin resistance (MIC >2 mg/L) in Europe. The four isolates with high-level resistance to azithromycin (MIC ≥256 mg/L) were widely separated in the phylogenomic tree and did not belong to any of the main clades. The main azithromycin resistance mechanisms were the A2059G mutation (high-level resistance) and the C2611T mutation (low- and moderate-level resistance) in the 23S rRNA gene.

O036 An outbreak of high level azithromycin resistant gonorrhoea in a UK city - Actions taken by the clinical team and lessons learnt

Background Between November 2014 and March 2015, eight high level azithromycin resistant Neisseria gonorrhoeae (NG) isolates (MIC > 256 mg/l) were identified by Sexually Transmitted Bacteria Reference Unit Microbiology Services (STBRU) from our clinic. An Outbreak Control Team was established to actively manage the outbreak. We report the actions and outcomes of the clinical team. Immediate actions Clinicians reminded to take cultures from all exposed sites when NG suspected and before any treatment; first face-to-face contact is most effective in obtaining partner details; TOC at 2 weeks essential. Enhanced PN commenced. Where initial PN incomplete, or withheld, at least two further attempts of face-to-face interview or phone call. TOC non-attendees contacted by phone call and letter, giving further opportunity to pursue PN. Advice sought from STBRU about treating pharyngeal infections to avoid pressure on ceftriaxone by its use as monotherapy. Investigation of how the first eight cases were missed despite clinic systems in place for checking positive NG cultures. Outcomes By December 2015: 16 infected people identified with whole genome sequencing suggesting clonal outbreak. All were heterosexual, most aged 16–20 years. No ethnic or geographic clustering. 12/16 attended for TOC which were negative. 28 contacts disclosed, 16 traceable all attended - 3 NG negative, 13 NG positive, (12/13 azithromycin resistant, 1 NAAT positive but culture negative). PN identified 1 cluster of 4 and 3 clusters of 2 Lessons learned NG cultures and sensitivities remain essential to detect antimicrobial resistance. Despite enhanced PN there are many untraceable contacts in young heterosexuals. Clinics need robust administrative systems for timely detection of antimicrobial resistance

Genomic Epidemiology and Molecular Resistance Mechanisms of Azithromycin-Resistant Neisseria gonorrhoeae in Canada from 1997 to 2014

The emergence of Neisseria gonorrhoeae strains with decreased susceptibility to cephalosporins and azithromycin (AZM) resistance (AZM(r)) represents a public health threat of untreatable gonorrhea infections. Genomic epidemiology through whole-genome sequencing was used to describe the emergence, dissemination, and spread of AZM(r) strains. The genomes of 213 AZM(r) and 23 AZM-susceptible N. gonorrhoeae isolates collected in Canada from 1989 to 2014 were sequenced. Core single nucleotide polymorphism (SNP) phylogenomic analysis resolved 246 isolates into 13 lineages. High-level AZM(r) (MICs ≥ 256 μg/ml) was found in 5 phylogenetically diverse isolates, all of which possessed the A2059G mutation (Escherichia coli numbering) in all four 23S rRNA alleles. One isolate with high-level AZM(r) collected in 2009 concurrently had decreased susceptibility to ceftriaxone (MIC = 0.125 μg/ml). An increase in the number of 23S rRNA alleles with the C2611T mutations (E. coli numbering) conferred low to moderate levels of AZM(r) (MICs = 2 to 4 and 8 to 32 μg/ml, respectively). Low-level AZM(r) was also associated with mtrR promoter mutations, including the -35A deletion and the presence of Neisseria meningitidis-like sequences. Geographic and temporal phylogenetic clustering indicates that emergent AZM(r) strains arise independently and can then rapidly expand clonally in a region through local sexual networks.

An outbreak of high-level azithromycin resistant Neisseria gonorrhoeae in England

ObjectivesTo investigate a potential outbreak of high-level azithromycin resistant (HL-AziR) gonococcal infections diagnosed in eight patients attending a sexual health clinic in Leeds, North England, between November 2014 and March...

001.2 Azithromycin-resistantneisseria gonorrhoeaein men who have sex with men (msm) in seattle, washington: 2014–2015

Background The emergence of azithromycin-resistant Neisseria gonorrhoeae threatens recommended first-line treatment regimens. Methods We investigated cases of azithromycin-resistant gonorrhoea detected at Public Health – Seattle and King County STD Clinic between January 2014 and February 2015. In 2012–2013, zero of 237 MSM urethral isolates were azithromycin-resistant. The US Centres for Disease Control and Prevention (CDC) and Clinical and Laboratory Standards Institute (CLSI) do not define an azithromycin-resistance breakpoint. CDC uses ≥2 mcg/mL as an “Alert Value” minimal inhibitory concentration (MIC) (here called resistant). We used agar dilution to determine MICs. Results Of 179 urethral, 83 pharyngeal and 87 rectal isolates from MSM, 11 (6.1%), 6 (7.2%) and 5 (5.7%) had azithromycin MIC ≥2 mcg/mL, respectively. We identified no cases of azithromycin-resistance among 56 heterosexuals. Overall, 19 (6.9%) of 276 MSM with culture-positive gonorrhoea had an azithromycin-resistant isolate. The median azithromycin MIC was 4.0 mcg/mL (range 2 to >256 mcg/mL). Eight patients’ isolates also demonstrated tetracycline resistance (MIC ≥2 mcg/mL); one was ciprofloxacin-resistant (MIC 16.0 mcg/mL). None exhibited reduced susceptibility to cefixime or ceftriaxone. Clinicians treated thirteen (68%) cases with ceftriaxone and azithromycin, one (5.3%) with ceftriaxone and doxycycline, two (10.6%) with study drug, and three (15.8%) with 2g of azithromycin. Two of three men treated with azithromycin-monotherapy had a test of cure (TOC) and both had persistent infection; their isolates demonstrated azithromycin MICs of 32 mcg/mL and 4.0 mcg/mL. One rectal treatment-failure was cured with 360 mg of gentamicin intramuscularly; the other (urethra/pharynx positive), was treated with ceftriaxone and doxycycline. He did not undergo repeat TOC. The individual with high-level azithromycin-resistance (MIC >256 mcg/mL) was an international traveller and not locatable for TOC. Conclusions Clinically important azithromycin-resistant Neisseria gonorrhoeae now are found in >5% of MSM with gonorrhoea in Seattle. These findings support new CDC recommendations to avoid treating gonorrhoea with azithromycin alone. Disclosure of interest statement This work was funded by the US National Institutes of Health and CDC. No pharmaceutical grants were received in the development of this study.

Emergence of Increased Azithromycin Resistance During Unsuccessful Treatment of Neisseria gonorrhoeae Infection With Azithromycin (Portland, OR, 2011)

We describe the emergence of an azithromycin-resistant Neisseria gonorrhoeae variant in a man from Portland, Oregon, during sole treatment with 2 g azithromycin. This report highlights the ease with which gonococcal macrolide resistance can emerge, the threat of multidrug resistant N. gonorrhoeae, and the need for adherence to Centers for Disease Control and Prevention treatment guidelines.

Emergence of High Level Azithromycin-Resistant Neisseria gonorrhoeae Strain Isolated in Argentina

One Neisseria gonorrhoeae strains highly resistant to azithromycin AzHLR (MIC >2048 mg/L) was isolated in Argentina in 2001 and it has been characterized by N. gonorrhoeae multiantigen sequence typing (NG-MAST) as ST696, suggesting a different event to other isolates in Europe. Neither, mtrR mutations or presence of mef gene were detected.

Azithromycin-resistant Neisseria gonorrhoeae strains recently isolated in Italy

The aim of this study was to characterize 22 azithromycin-resistant Neisseria gonorrhoeae isolates, collected in Italy from January 2007 through June 2008, during a study of the prevalence of antibiotic resistance. MICs of azithromycin, ciprofloxacin, ceftriaxone, penicillin and tetracycline were determined by the Etest method. Azithromycin-resistant strains (MIC > or = 1 mg/L) were genetically analysed by N. gonorrhoeae multi-antigen sequence typing (NG-MAST) and PFGE. A total of 22 azithromycin-resistant isolates were found among the 219 collected. Five of the 22 isolates showed high-level azithromycin resistance (MICs of 128 or 256 mg/L). Sixteen of the 22 were isolated from men who have sex with men. Among the 14 sequence types (STs) found by NG-MAST, 5 STs, containing clusters of two, three or four strains, were homogeneous with respect to epidemiology and/or antibiotic susceptibility. PFGE divided the 22 strains into two main groups that were possibly related. This is the first report of gonococci with high-level resistance to azithromycin circulating in Italy. Correlation between NG-MAST results and epidemiological data for some of the analysed strains and patients could be established. This study represents a reference point for future surveillance in Italy and suggests the need to add azithromycin to the antibiotic susceptibility panel for gonococci.