Whole-genome sequencing resolves biochemical misidentification of Neisseria species from urogenital specimens.

Neisseria meningitidis (Nm) and Neisseria gonorrhoeae (Ng) are human pathogens that sometimes occupy the same anatomical niche. Ng, the causative agent of gonorrhea, infects 87 million individuals annually worldwide and is an urgent threat due to increasing drug resistance. Ng is a pathogen of the urogenital tract and may infect the oropharyngeal or rectal site, often asymptomatically. Conversely, Nm is an opportunistic pathogen. While often a commensal in the oropharyngeal tract, it is also the leading cause of bacterial meningitis with 1.2 million cases globally, causing significant morbidity and mortality. Horizontal gene transfer (HGT) is likely to occur between Ng and Nm due to their shared anatomical niches and genetic similarity, which poses challenges for accurate detection and treatment. Routine surveillance through the Gonococcal Isolate Surveillance Project and Strengthening the U.S. Response to Resistant Gonorrhea detected six concerning urogenital Neisseria isolates with contradicting species identification in Milwaukee (MIL). While all six isolates were positive for Ng using nucleic acid amplification testing (NAAT) and matrix-assisted laser desorption/ionization time of flight identified the isolates as Ng, two biochemical tests, Gonochek-II and API NH, classified them as Nm. To address this discrepancy, we performed whole-genome sequencing (WGS) using Illumina MiSeq on all isolates and employed various bioinformatics tools. Species detection analysis using BMScan, which uses WGS data, identified all isolates as Ng. Furthermore, Kraken revealed over 98% of WGS reads mapped to the Ng genome and <1% to Nm. Recombination analysis identified putative HGT in all MIL isolates within the γ-glutamyl transpeptidase (ggt) gene, a key component in the biochemical tests used to differentiate between Nm and Ng. Further analysis identified Nm as the source of HGT event. Specifically, the active Nm ggt gene replaced the Ng pseudogenes, ggt1 and ggt2. Together, this study demonstrates that closely related Neisseria species sharing a niche underwent HGT, which led to the misidentification of species following biochemical testing. Importantly, NAAT accurately detected Ng. The misidentification highlights the importance of using WGS to continually evaluate diagnostic or bacterial identification tests.

Assessing the National Representativeness of Estimates of Antimicrobial-Resistant Urogenital Neisseria gonorrhoeae in US Men, Gonococcal Isolate Surveillance Project, 2008-2018.

BACKGROUND: The percentage of Neisseria gonorrhoeae (GC) isolates with resistance or elevated minimum inhibitory concentrations to antimicrobials has steadily increased. Current estimates are based on the Gonococcal Isolate Surveillance Project (GISP), a sentinel surveillance study of male GC in the United States. This analysis seeks to assess for adjustment before treating aggregated GISP estimates as nationally representative of all reported male urogenital infections. METHODS: We used multilevel regression with poststratification (MRP) to compute national estimates of the proportion of antimicrobial resistance (AMR) (defined as exceeding minimum inhibitory concentration thresholds) in male GC using data from 2008 to 2018 GISP and case reports. Sensitivity analyses investigated the impact of analysis assumptions and unmeasured variables. We additionally produced estimates of 2018 AMR GC cases among US men. RESULTS: National estimates were consistent with unweighted estimates. The estimated proportion of incident AMR GC infections in men with urogenital GC in 2018 was 51.5% (95% confidence interval [CI], 50.1%-52.9%), equating to an estimated 366,300 incident AMR GC infections in US men aged 15 to 39 years. Estimates of AMR for tested antimicrobials in male GC infections in 2018 ranged from 0.16% (95% CI, 0.08%-0.24%) for ceftriaxone to 29.9% (95% CI, 28.6%-31.1%) for ciprofloxacin. Sensitivity analyses revealed that unmeasured data on sex of sex partners could substantially impact weighted estimates. CONCLUSIONS: Antimicrobial resistance among reported incident male urogenital GC infections remains rare for ceftriaxone, the current standard of care. Aggregated GISP data are generally representative of men in the US who are reported with urogenital gonorrhea.

Sustained Transmission of Neisseria gonorrhoeae with High-Level Resistance to Azithromycin, in Indianapolis, Indiana, 2017-2018.

BACKGROUND: Since 2014, Neisseria gonorrhoeae azithromycin (AZM) susceptibility has declined in the United States, but high-level AZM resistance (HL-AZMR) has been infrequent and sporadic. We describe a cluster of 14 N. gonorrhoeae isolates with HL-AZMR identified in Indianapolis over 13 months. METHODS: N. gonorrhoeae culture specimens (genital and extragenital) were collected from attendees of the Bell Flower Clinic. Isolates underwent antimicrobial susceptibility testing (AST) using Etest. AZM minimum inhibitory concentrations ≥256 µg/mL were classified as HL-AZMR. Local disease intervention specialists interviewed patients whose isolates demonstrated HL-AZMR and conducted partner services. Relatedness of isolates was investigated by genomic analyses. RESULTS: During 2017-2018, AST was performed in 1016 N. gonorrhoeae isolates collected at the Bell Flower Clinic. Fourteen isolates (1.4%) from 12 men collected over 13 months demonstrated HL-AZMR; all were cephalosporin susceptible. Of the 12 men, 9 were white and reported male sex partners. Nine of the men were able to be retested; all were cured with 250-mg ceftriaxone plus 1-g AZM. Two men named each other as partners; no other partners in common were reported. Genomic analysis demonstrated close relatedness of the HL-AZMR isolates and a novel combination of a mosaic-mtrR promoter along with 23S ribosomal RNA mutations that appear to have emerged from circulating strains. CONCLUSIONS: The close genetic relatedness with limited epidemiologic linkages between patients highlights the challenges of gonorrhea partner investigations and suggests undetected local transmission. Local AST, rapid public health action, and epidemiologic investigations combined with genomic analysis provides a multipronged approach to understanding an outbreak of sexually transmitted disease.

Atypical Mutation in Neisseria gonorrhoeae 23S rRNA Associated with High-Level Azithromycin Resistance.

A2059G mutation in the 23S rRNA gene is the only reported mechanism conferring high-level azithromycin resistance (HL-AZMR) in Neisseria gonorrhoeae Through U.S. gonococcal antimicrobial resistance surveillance projects, we identified four HL-AZMR gonococcal isolates lacking this mutational genotype. Genetic analysis revealed an A2058G mutation of 23S rRNA alleles in all four isolates. In vitro selected gonococcal strains with homozygous A2058G recapitulated the HL-AZMR phenotype. Taken together, we postulate that the A2058G mutation confers HL-AZMR in N. gonorrhoeae.

Outcomes of Traditional and Enhanced Gonorrhea Partner Services in the Strengthening the US Response to Resistant Gonorrhea Project, 2017 to 2019.

INTRODUCTION: The Centers for Disease Control and Prevention implemented Strengthening the US Response to Resistant Gonorrhea (SURRG) to build local detection and response capacity and evaluate responses to antibiotic-resistant gonorrhea outbreaks, including partner services for gonorrhea. We evaluated outcomes of traditional partner services conducted under SURRG, which involved (1) counseling index patients and eliciting sexual partners; (2) interviewing, testing, and treating partners; and (3) providing partner services to partners newly diagnosed with gonorrhea. We also evaluated outcomes of enhanced partner services, which additionally involved interviewing and testing partners of persons who tested negative, and social contacts of index patients and partners. METHODS: We analyzed partner services investigation data from 8 jurisdictions participating in SURRG from 2017 to 2019. We summed total index patients, partners from traditional partner services, and partners and contacts from enhanced partner services, and calculated partner services outcomes among partners and contacts. We also visualized sexual networks from partner services data. RESULTS: Of 1242 index patients identified, 506 named at least 1 sexual partner. Traditional partner services yielded 1088 sexual partners, and 105 were newly diagnosed with gonorrhea. Enhanced partner services yielded an additional 59 sexual partners and 52 social contacts. Of those partners and contacts, 3 were newly diagnosed with gonorrhea. Network visualization revealed sparse networks with few complex partnership clusters. CONCLUSIONS: Traditional partner services for gonorrhea may be useful for eliciting, notifying, and diagnosing partners of index patients in an outbreak setting. Enhanced partner services are unlikely to be effective for eliciting, notifying, and diagnosing a substantial number of additional people.

Enhancing U.S. Local, State, and Federal Preparedness Through Simulated Interactive Tabletop Exercises of a Mock Antibiotic-Resistant Gonorrhea Outbreak, 2018-2019.

BACKGROUND: Responding effectively to outbreaks of antibiotic-resistant gonorrhea (ARGC) in the future will likely prove challenging. Tabletop exercises (TTXs) may assist local, state, and federal public health officials evaluate existing ARGC outbreak response plans, strengthen preparedness and response effectiveness, and identify critical gaps to address before an outbreak. METHODS: In 2018 to 2019, Centers for Disease Control and Prevention (CDC) collaborated with state partners to develop and implement TTXs to simulate a public health emergency involving an ARGC outbreak. Before the TTXs, 2 state-local health department pairs developed ARGC outbreak response plans. During each 1-day exercise (in Indiana and Illinois), participants discussed roles, clinical management, public health response, and communication based on predeveloped response plans. Observers identified outbreak response strengths and gaps, and participants completed feedback forms. RESULTS: Forty-one (Illinois) and 48 people (Indiana) participated in each TTX, including sexually transmitted disease clinical staff, laboratorians, public health infectious disease program staff, and CDC observers. Strengths and gaps varied by jurisdiction, but identified gaps included: (1) local access to gonorrhea culture and timely antimicrobial susceptibility testing, (2) protocols for clinical management of suspected treatment failures, (3) communication plans, and (4) clarity regarding state and local responsibilities. The CDC observers identified opportunities to provide national-level technical assistance, foster local antimicrobial susceptibility testing, and develop further response guidance. Tabletop exercises summary reports were used to guide modifications to local response plans to address gaps. CONCLUSIONS: The TTXs allowed participants to practice responding to a simulated public health emergency and may have enhanced local response capacity. Centers for Disease Control and Prevention made TTX implementation materials publicly available.

Genomic Analysis of the Predominant Strains and Antimicrobial Resistance Determinants Within 1479 Neisseria gonorrhoeae Isolates From the US Gonococcal Isolate Surveillance Project in 2018.

BACKGROUND: The prevalence of Neisseria gonorrhoeae (GC) isolates with elevated minimum inhibitory concentrations to various antibiotics continues to rise in the United States and globally. Genomic analysis provides a powerful tool for surveillance of circulating strains, antimicrobial resistance determinants, and understanding of transmission through a population. METHODS: Neisseria gonorrhoeae isolates collected from the US Gonococcal Isolate Surveillance Project in 2018 (n = 1479) were sequenced and characterized. Whole-genome sequencing was used to identify sequence types, antimicrobial resistance profiles, and phylogenetic relationships across demographic and geographic populations. RESULTS: Genetic characterization identified that (1) 80% of the GC isolates were represented in 33 multilocus sequence types, (2) isolates clustered in 23 major phylogenetic clusters with select phenotypic and demographic prevalence, and (3) common antimicrobial resistance determinants associated with low-level or high-level decreased susceptibility or resistance to relevant antibiotics. CONCLUSIONS: Characterization of this 2018 Gonococcal Isolate Surveillance Project genomic data set, which is the largest US whole-genome sequence data set to date, sets the basis for future prospective studies, and establishes a genomic baseline of GC populations for local and national monitoring.

Test of Cure Return Rate and Test Positivity, Strengthening the US Response to Resistant Gonorrhea, United States, 2018-2019.

BACKGROUND: Reduced antibiotic susceptibility (RS) in Neisseria gonorrhoeae (GC) may increase treatment failure. Conducting tests of cure (TOC) for patients with RS-GC may facilitate identification of treatment failures. METHODS: We examined 2018 to 2019 data from 8 jurisdictions participating in the US Centers for Disease Control and Prevention's Strengthening US Response to Resistant Gonorrhea project. Jurisdictions collected GC isolates and epidemiological data from patients and performed antimicrobial susceptibility testing. Minimum inhibitory concentrations of ceftriaxone, 0.125 µg/mL or greater; cefixime, 0.250 µg/mL or greater; or azithromycin, 2.0 µg/mL or greater were defined as RS. Patients with RS infections were asked to return for a TOC 8 to 10 days posttreatment. We calculated a weighted TOC return rate and described time to TOC and suspected reasons for any positive TOC results. RESULTS: Overall, 1165 patients were diagnosed with RS infections. Over half returned for TOC (weighted TOC, 61%; 95% confidence interval, 50.1%-72.6%; range by jurisdiction, 32%-80%). Test of cure rates were higher among asymptomatic (68%) than symptomatic patients (53%, P = 0.001), and men who have sex with men (62%) compared with men who have sex with women (50%; P < 0.001). Median time between treatment and TOC was 12 days (interquartile range, 9-16). Of the 31 (4.5%) TOC patients with positive results, 13 (42%) were suspected because of reinfection and 11 (36%) because of false-positive results. There were no treatment failures suspected to be due to RS-GC. CONCLUSIONS: Most patients with a RS infection returned for a TOC, though return rates varied by jurisdiction and patient characteristics. Test of cure can identify and facilitate treatment of reinfections, but false-positive TOC results may complicate interpretation and clinical management.

Implementation and Evaluation of Gradient Strip Antimicrobial Susceptibility Testing in US Public Health Laboratories to Respond to Resistant Gonorrhea.

BACKGROUND: Gradient strip antimicrobial susceptibility testing using Etest is conducted by local public health jurisdictions participating in the Strengthening the US Response to Resistant Gonorrhea (SURRG) program to inform public health responses to resistant gonorrhea. Proficiency testing results across the participating laboratories were analyzed and a comparison of Etest with the agar dilution method was conducted. METHODS: Laboratories participating in SURRG performed Etest for azithromycin (AZM), cefixime (CFX), and ceftriaxone (CRO). Concurrence between minimum inhibitory concentrations (MICs) obtained with Etest versus the agar dilution method using corresponding isolates was defined as ±1 double dilution. Specific levels of reduced susceptibility were termed "alerts" and included isolates with the following MICs: ≥2.0 µg/mL (AZM), ≥0.25 µg/mL (CFX), and ≥0.125 µg/mL (CRO). Categorical (alert/nonalert) agreement was calculated for MICs determined using Etest and agar dilution methods. RESULTS: Strengthening the US Response to Resistant Gonorrhea laboratories had high proficiency testing scores (≥98%) and low levels of interlaboratory variations in MICs. The overall concurrence of MICs (essential agreement) determined using agar dilution, and Etest was 96% (CRO), 96% (CFX), and 95% (AZM). Depending on the antibiotic tested, between 27% and 66% of isolates with alert MICs determined by Etest also had alert MICs using the reference agar dilution methodology; however, most of these alert MICs were detected at threshold levels. CONCLUSIONS: This study demonstrates that MICs produced by SURRG laboratories using Etest have a high level of concurrence with agar dilution. Although confirmation of specific alert MICs varied, Etest facilities rapid detection and response to emerging resistant gonorrhea.

Impact of Anatomic Site, Specimen Collection Timing, and Patient Symptom Status on Neisseria gonorrhoeae Culture Recovery.

BACKGROUND: Neisseria gonorrhoeae culture is required for antimicrobial susceptibility testing, but recovering isolates from clinical specimens is challenging. Although many variables influence culture recovery, studies evaluating the impact of culture specimen collection timing and patient symptom status are limited. This study analyzed urogenital and extragenital culture recovery data from Centers for Disease Control and Prevention's Strengthening the US Response to Resistant Gonorrhea (SURRG) program, a multisite project, which enhances local N. gonorrhoeae culture and antimicrobial susceptibility testing capacity. METHODS: Eight SURRG jurisdictions collected gonococcal cultures from patients with N. gonorrhoeae-positive nucleic acid amplification test (NAAT) results attending sexually transmitted disease and community clinics. Matched NAAT and culture specimens from the same anatomic site were collected, and culture recovery was assessed. Time between NAAT and culture specimen collection was categorized as same day, 1 to 7 days, 8 to 14 days, or ≥15 days, and patient symptoms were matched to the anatomic site where culture specimens were collected. RESULTS: From 2018 to 2019, among persons with N. gonorrhoeae-positive NAAT, urethral infections resulted in the highest culture recovery (5927 of 6515 [91.0%]), followed by endocervical (222 of 363 [61.2%]), vaginal (63 of 133 [47.4%]), rectal (1117 of 2805 [39.8%]), and pharyngeal (1019 of 3678 [27.7%]) infections. Culture recovery was highest when specimens were collected on the same day as NAAT specimens and significantly decreased after 7 days. Symptoms were significantly associated with culture recovery at urethral (P = <0.0001) and rectal (P = <0.0001) sites of infection but not endocervical, vaginal, or pharyngeal sites. CONCLUSIONS: Culture specimen collection timing and patient symptomatic status can impact culture recovery. These findings can guide decisions about culture collection protocols to maximize culture recovery and strengthen detection of antimicrobial-resistant infections.

Demographic and Epidemiological Characteristics Associated With Reduced Antimicrobial Susceptibility to Neisseria gonorrhoeae in the United States, Strengthening the US Response to Resistant Gonorrhea, 2018 to 2019.

BACKGROUND: Jurisdictions participating in Strengthening the US Response to Resistant Gonorrhea (SURRG) implemented specimen collection for culture and antimicrobial susceptibility testing from a sample of persons of all genders (at multiple anatomic sites) attending sexually transmitted disease clinics and community clinics. We describe the percentage and characteristics of patients whose isolates demonstrated reduced susceptibility (RS) to azithromycin, ceftriaxone, or cefixime. METHODS: We included patients from clinics that participated in SURRG whose isolates underwent antimicrobial susceptibility testing by Etest. We defined RS as azithromycin minimum inhibitory concentrations (MICs) ≥2 µg/mL (AZM-RS), ceftriaxone MICs ≥0.125 µg/mL (CRO-RS), or cefixime MICs ≥0.25 µg/mL (CFX-RS). Patients with repeated infections appeared >1 time in the data. We calculated the frequency and percentage of patients with an isolate demonstrating RS by epidemiological characteristics. RESULTS: During the period 2018-2019, 10,013 patients from 8 jurisdictions provided 10,735 isolates. Among 10,013 patients, 11.0% (n = 1099) had ≥1 isolate with AZM-RS (range by jurisdiction, 2.5%-18.0%). Approximately 11.3% of 8771 of patients visiting sexually transmitted disease clinics and approximately 8.8% of 1242 patients visiting community clinics had an AZM-RS isolate. Nearly 6% of 1013 females had an AZM-RS isolate; among males, the percents of patients with an AZM-RS isolate were 17.7% among 4177 men who have sex only with men and 6.1% among 3581 men who have sex only with women. Few (0.4%) patients had isolates with CFX-RS (n = 40) or CRO-RS (n = 43). CONCLUSIONS: Although infections with reduced cephalosporin susceptibility were rare, AZM-RS infections were prevalent in this sample of patients in multiple jurisdictions and across gender and gender of sex partner categories.

Enhancing Gonococcal Antimicrobial Resistance Surveillance in Cisgender Women, Strengthening the US Response to Resistant Gonorrhea, 2018 to 2019.

BACKGROUND: Cisgender women have been underrepresented in antibiotic-resistant gonorrhea (ARGC) surveillance systems. Three of 8 project sites (City of Milwaukee [MIL], Guilford County [GRB], Denver County [DEN]), funded under the Centers for Disease Control and Prevention's Strengthening the US Response to Resistant Gonorrhea (SURRG), focused efforts to better include cisgender women in ARGC surveillance. METHODS: MIL, GRB, and DEN partnered with diverse health care settings and developed gonorrhea culture criteria to facilitate urogenital specimen collection in cisgender women and men. Regional laboratories within the Antibiotic Resistance Laboratory Network performed agar dilution antibiotic susceptibility testing (AST) of gonococcal isolates. Data from 2018 and 2019 were analyzed. RESULTS: In SURRG, 90.5% (11,464 of 12,667) of the cisgender women from whom urogenital culture specimens were collected were from MIL, GRB, and DEN. Of women in SURRG whose gonococcal isolates underwent AST, 70% were from these 3 sites. In these 3 sites, a substantial proportion of cisgender women with positive urogenital cultures and AST were from health care settings other than sexually transmitted disease (STD) clinics (non-STD clinics; MIL, 56.0%; GRB, 80.4%; and DEN, 23.5%). Isolates with AST were obtained from 5.1%, 10.2%, and 2.4% of all diagnosed gonorrhea cases among cisgender women in MIL, GRB, and DEN, respectively, and were more often susceptible to all antibiotics than those from cisgender men from each of these sites. CONCLUSIONS: With focused efforts and partnerships with non-STD clinics, 3 SURRG sites were able to include robust ARGC surveillance from cisgender women. These findings may guide further efforts to improve gender equity in ARGC surveillance.

Strengthening the US Response to Resistant Gonorrhea: An Overview of a Multisite Program to Enhance Local Response Capacity for Antibiotic-Resistant Neisseria gonorrhoeae.

BACKGROUND: In 2016, Centers for Disease Control and Prevention initiated Strengthening the US Response to Resistant Gonorrhea (SURRG) in multiple jurisdictions to enhance antibiotic resistant gonorrhea rapid detection and response infrastructure and evaluate the impact of key strategies. METHODS: Eight jurisdictions were funded to establish or enhance local gonococcal culture specimen collection in sexually transmitted disease and community clinics, conduct rapid antimicrobial susceptibility testing (AST) in local laboratories, modify systems for enhanced data collection and rapid communication of results, and initiate enhanced partner services among patients with gonorrhea demonstrating elevated minimum inhibitory concentrations (MICs) to ceftriaxone, cefixime or azithromycin. RESULTS: Grantees incorporated genital, pharyngeal, and rectal gonococcal culture collection from all genders at participating clinics. During 2018 to 2019, grantees collected 58,441 culture specimens from 46,822 patients and performed AST on 10,814 isolates (representing 6.8% [3412] and 8.9% [4883] of local reported cases in 2018 and 2019, respectively). Of isolates that underwent AST, 11% demonstrated elevated azithromycin MICs; fewer than 0.5% demonstrated elevated ceftriaxone or cefixime MICs. Among patients whose infections demonstrated elevated MICs, 81.7% were interviewed for partner elicitation; however, limited new cases were identified among partners and contacts. CONCLUSIONS: As a public health model to build capacity to slow the spread of emerging resistance, SURRG successfully expanded culture collection, implemented rapid AST, and implemented an enhanced partner services investigation approach in participating jurisdictions. Findings from SURRG may enhance preparedness efforts and inform a longer-term, comprehensive, and evidence-based public health response to emerging gonococcal resistance. Continued development of innovative approaches to address emerging resistance is needed.

Antimicrobial Susceptibility of Urogenital and Extragenital Neisseria gonorrhoeae Isolates Among Men Who Have Sex With Men: Strengthening the US Response to Resistant Gonorrhea and Enhanced Gonococcal Isolate Surveillance Project, 2018 to 2019.

BACKGROUND: We investigated differences in gonococcal antimicrobial susceptibility by anatomic site among cisgender men who have sex with men (MSM) using specimens collected through the Centers for Disease Control and Prevention's enhanced Gonococcal Isolate Surveillance Project and Strengthening the US Response to Resistant Gonorrhea. METHODS: During the period January 1, 2018-December 31, 2019, 12 enhanced Gonococcal Isolate Surveillance Project and 8 Strengthening the US Response to Resistant Gonorrhea sites collected urogenital, pharyngeal, and rectal isolates from cisgender MSM in sexually transmitted disease clinics. Gonococcal isolates were sent to regional laboratories for antimicrobial susceptibility testing by agar dilution. To account for correlated observations, linear mixed-effects models were used to calculate geometric mean minimum inhibitory concentrations (MICs), and mixed-effects logistic regression models were used to calculate the proportion of isolates with elevated or resistant MICs; comparisons were made across anatomic sites. RESULTS: Participating clinics collected 3974 urethral, 1553 rectal, and 1049 pharyngeal isolates from 5456 unique cisgender MSM. There were no significant differences in the geometric mean MICs for azithromycin, ciprofloxacin, penicillin, and tetracycline by anatomic site. For cefixime and ceftriaxone, geometric mean MICs for pharyngeal isolates were higher compared with anogenital isolates (P < 0.05). The proportion of isolates with elevated ceftriaxone MICs (≥0.125 µg/mL) at the pharynx (0.67%) was higher than at rectal (0.13%) and urethral (0.18%) sites (P < 0.05). CONCLUSIONS: Based on data collected from multijurisdictional sentinel surveillance projects, antimicrobial susceptibility patterns of Neisseria gonorrhoeae isolates may differ among MSM at extragenital sites, particularly at the pharynx. Continued investigation into gonococcal susceptibility patterns by anatomic site may be an important strategy to monitor and detect the emergence of antimicrobial resistant gonorrhea over time.

Genomic Characterization of Neisseria gonorrhoeae Strains from 2016 U.S. Sentinel Surveillance Displaying Reduced Susceptibility to Azithromycin.

In 2016, the proportion of Neisseria gonorrhoeae isolates with reduced susceptibility to azithromycin rose to 3.6%. A phylogenetic analysis of 334 N. gonorrhoeae isolates collected in 2016 revealed a single, geographically diverse lineage of isolates with MICs of 2 to 16 µg/ml that carried a mosaic-like mtr locus, whereas the majority of isolates with MICs of ≥16 µg/ml appeared sporadically and carried 23S rRNA mutations. Continued molecular surveillance of N. gonorrhoeae isolates will identify new resistance mechanisms.

Expanding U.S. Laboratory Capacity for Neisseria gonorrhoeae Antimicrobial Susceptibility Testing and Whole-Genome Sequencing through the CDC's Antibiotic Resistance Laboratory Network.

U.S. gonorrhea rates are rising, and antibiotic-resistant Neisseria gonorrhoeae (AR-Ng) is an urgent public health threat. Since implementation of nucleic acid amplification tests for N. gonorrhoeae identification, the capacity for culturing N. gonorrhoeae in the United States has declined, along with the ability to perform culture-based antimicrobial susceptibility testing (AST). Yet AST is critical for detecting and monitoring AR-Ng. In 2016, the CDC established the Antibiotic Resistance Laboratory Network (AR Lab Network) to shore up the national capacity for detecting several resistance threats including N. gonorrhoeae AR-Ng testing, a subactivity of the CDC's AR Lab Network, is performed in a tiered network of approximately 35 local laboratories, four regional laboratories (state public health laboratories in Maryland, Tennessee, Texas, and Washington), and the CDC's national reference laboratory. Local laboratories receive specimens from approximately 60 clinics associated with the Gonococcal Isolate Surveillance Project (GISP), enhanced GISP (eGISP), and the program Strengthening the U.S. Response to Resistant Gonorrhea (SURRG). They isolate and ship up to 20,000 isolates to regional laboratories for culture-based agar dilution AST with seven antibiotics and for whole-genome sequencing of up to 5,000 isolates. The CDC further examines concerning isolates and monitors genetic AR markers. During 2017 and 2018, the network tested 8,214 and 8,628 N. gonorrhoeae isolates, respectively, and the CDC received 531 and 646 concerning isolates and 605 and 3,159 sequences, respectively. In summary, the AR Lab Network supported the laboratory capacity for N. gonorrhoeae AST and associated genetic marker detection, expanding preexisting notification and analysis systems for resistance detection. Continued, robust AST and genomic capacity can help inform national public health monitoring and intervention.

Utility of MALDI-TOF MS for differentiation of Neisseria gonorrhoeae isolates with dissimilar azithromycin susceptibility profiles.

BACKGROUND: Antibiotic-resistant gonorrhoea has been a chronic public health burden since the mid-1930s. Recent emergence of isolates resistant to the current recommended antibiotics for gonorrhoea further magnifies the threat of untreatable gonorrhoea. The lack of new, effective antibiotics highlights the need for better understanding of the population structure of Neisseria gonorrhoeae in order to provide greater insight on how to curtail the spread of antimicrobial-resistant N. gonorrhoeae. OBJECTIVES: To explore a potential application of MALDI-TOF MS to differentiate N. gonorrhoeae displaying different levels of susceptibility to the antibiotic azithromycin. METHODS: We conducted MALDI-TOF MS using the Bruker Biotyper on 392 N. gonorrhoeae isolates collected through the Gonococcal Isolate Surveillance Project (GISP) and/or the Strengthening the United States Response to Resistant Gonorrhea (SURRG) project. The MALDI-TOF MS spectra were visually analysed to assess the presence of distinctive peak(s). Statistical analysis was performed to assess the relationship between gonococcal isolates with the distinct protein peak and antibiotic susceptibility. RESULTS: In this study, we were able to differentiate N. gonorrhoeae isolates into two distinct subpopulations using MALDI-TOF MS. Isolates were distinguished by the presence or absence of a spectral peak at 11 300 Da. Notably, these two groups exhibited different levels of susceptibility to azithromycin. CONCLUSIONS: We have shown that in addition to its ability to identify N. gonorrhoeae, MALDI-TOF MS could also be used to differentiate gonococcal isolates with different levels of susceptibility to azithromycin.

Update to CDC's Treatment Guidelines for Gonococcal Infection, 2020.

Sexually transmitted infections (STIs) caused by the bacteria Neisseria gonorrhoeae (gonococcal infections) have increased 63% since 2014 and are a cause of sequelae including pelvic inflammatory disease, ectopic pregnancy, and infertility and can facilitate transmission of human immunodeficiency virus (HIV) (1,2). Effective treatment can prevent complications and transmission, but N. gonorrhoeae's ability to acquire antimicrobial resistance influences treatment recommendations and complicates control (3). In 2010, CDC recommended a single 250 mg intramuscular (IM) dose of ceftriaxone and a single 1 g oral dose of azithromycin for treatment of uncomplicated gonococcal infections of the cervix, urethra, and rectum as a strategy for preventing ceftriaxone resistance and treating possible coinfection with Chlamydia trachomatis (4). Increasing concern for antimicrobial stewardship and the potential impact of dual therapy on commensal organisms and concurrent pathogens (3), in conjunction with the continued low incidence of ceftriaxone resistance and the increased incidence of azithromycin resistance, has led to reevaluation of this recommendation. This report, which updates previous guidelines (5), recommends a single 500 mg IM dose of ceftriaxone for treatment of uncomplicated urogenital, anorectal, and pharyngeal gonorrhea. If chlamydial infection has not been excluded, concurrent treatment with doxycycline (100 mg orally twice a day for 7 days) is recommended. Continuing to monitor for emergence of ceftriaxone resistance through surveillance and health care providers' reporting of treatment failures is essential to ensuring continued efficacy of recommended regimens.

Evidence of Recent Genomic Evolution in Gonococcal Strains With Decreased Susceptibility to Cephalosporins or Azithromycin in the United States, 2014-2016.

BACKGROUND: Given the lack of new antimicrobials or a vaccine, understanding the evolutionary dynamics of Neisseria gonorrhoeae is a significant public and global health priority. We investigated the emergence and spread of gonococcal strains with decreased susceptibility to cephalosporins and azithromycin using detailed genomic analyses of gonococcal isolates collected in the United States, 2014-2016. METHODS: We sequenced genomes of 649 isolates collected through the Gonococcal Isolate Surveillance Project. We examined the genetic relatedness of isolates and assessed associations between clades and various genotypic and phenotypic combinations. RESULTS: We identified a large and clonal lineage of strains (MLST ST9363) associated with elevated azithromycin minimum inhibitory concentration (AZIem), characterized by a mosaic mtr locus (C substitution in the mtrR promoter, mosaic mtrR and mtrD). Mutations in 23S rRNA were sporadically distributed among AZIem strains. Another clonal group (MLST ST1901) possessed 7 unique PBP2 patterns, and it shared common mutations in other genes associated with cephalosporin resistance. CONCLUSIONS: Whole-genome sequencing methods can enhance monitoring of antimicrobial resistant gonococcal strains by identifying gonococcal populations containing mutations of concern. These methods could inform the development of point-of-care diagnostic tests designed to determine the specific antibiotic susceptibility profile of a gonococcal infection in a patient.

Emergence of Neisseria gonorrhoeae Strains Harboring a Novel Combination of Azithromycin-Attenuating Mutations.

The nimbleness of Neisseria gonorrhoeae to evade the effect of antibiotics has perpetuated the fight against antibiotic-resistant gonorrhea for more than 80 years. The ability to develop resistance to antibiotics is attributable to its indiscriminate nature in accepting and integrating exogenous DNA into its genome. Here, we provide data demonstrating a novel combination of the 23S rRNA A2059G mutation with a mosaic-multiple transferable resistance (mosaic-mtr) locus haplotype in 14 N. gonorrhoeae isolates with high-level azithromycin MICs (≥256 µg/ml), a combination that may confer more fitness than in previously identified isolates with high-level azithromycin resistance. To our knowledge, this is the first description of N. gonorrhoeae strains harboring this novel combination of resistance determinants. These strains were isolated at two independent jurisdictions participating in the Gonococcal Isolate Surveillance Project (GISP) and in the Strengthening the U.S. Response to Resistant Gonorrhea (SURRG) project. The data suggest that the genome of N. gonorrhoeae continues to shuffle its genetic material. These findings further illuminate the genomic plasticity of N. gonorrhoeae, which allows this pathogen to develop mutations to escape the inhibitory effects of antibiotics.