Surveillance for Disseminated Gonococcal Infections, Active Bacterial Core surveillance (ABCs) - United States, 2015-2019

Antimicrobial activity of compounds identified by artificial intelligence discovery engine targeting enzymes involved in Neisseria gonorrhoeae peptidoglycan metabolism

BACKGROUND

Neisseria gonorrhoeae (Ng) causes the sexually transmitted disease gonorrhoea. There are no vaccines and infections are treated principally with antibiotics. However, gonococci rapidly develop resistance to every antibiotic class used and there is a need for developing new antimicrobial treatments. In this study we focused on two gonococcal enzymes as potential antimicrobial targets, namely the serine protease L,D-carboxypeptidase LdcA (NgO1274/NEIS1546) and the lytic transglycosylase LtgD (NgO0626/NEIS1212). To identify compounds that could interact with these enzymes as potential antimicrobials, we used the AtomNet virtual high-throughput screening technology. We then did a computational modelling study to examine the interactions of the most bioactive compounds with their target enzymes. The identified compounds were tested against gonococci to determine minimum inhibitory and bactericidal concentrations (MIC/MBC), specificity, and compound toxicity in vitro.

RESULTS

AtomNet identified 74 compounds that could potentially interact with Ng-LdcA and 84 compounds that could potentially interact with Ng-LtgD. Through MIC and MBC assays, we selected the three best performing compounds for both enzymes. Compound 16 was the most active against Ng-LdcA, with a MIC50 value < 1.56 µM and MBC50/90 values between 0.195 and 0.39 µM. In general, the Ng-LdcA compounds showed higher activity than the compounds directed against Ng-LtgD, of which compound 45 had MIC50 values of 1.56-3.125 µM and MBC50/90 values between 3.125 and 6.25 µM. The compounds were specific for gonococci and did not kill other bacteria. They were also non-toxic for human conjunctival epithelial cells as judged by a resazurin assay. To support our biological data, in-depth computational modelling study detailed the interactions of the compounds with their target enzymes. Protein models were generated in silico and validated, the active binding sites and amino acids involved elucidated, and the interactions of the compounds interacting with the enzymes visualised through molecular docking and Molecular Dynamics Simulations for 50 ns and Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA).

CONCLUSIONS

We have identified bioactive compounds that appear to target the N. gonorrhoeae LdcA and LtgD enzymes. By using a reductionist approach involving biological and computational data, we propose that compound Ng-LdcA-16 and Ng-LtgD-45 are promising anti-gonococcal compounds for further development.

Antimicrobial Resistance in Gonorrhea

Antimicrobial resistance is a global public health emergency. The World Health Organization recently highlighted the growing number of new sexually transmitted infections such as gonorrhea, syphilis, and Chlamydia, which are resistant to common antibiotics. The phenomenon is also on the rise due to increasing intercontinental travel. Emerging antibiotic-resistant strains of gonorrhea are particularly associated with international spread from Southeast Asian travelers. Infection with Neisseria gonorrhoeae can cause a wide spectrum of associated diseases such as dermatitis, arthritis and septic arthritis, and pelvic inflammatory disease, and can even lead to serious health consequences for the individual. Natural infection confers no immunity, and vaccination is not available currently, although in several countries, it has been reported that the antimeningococcal vaccine may protect against gonorrhea. Implementing all necessary preventive measures is crucial, as well as appropriate and timely diagnostic methods and effective antimicrobial therapeutic treatments in the correct modalities to avoid the increase of forms of gonorrhea that are resistant to common antibiotics and difficult to eradicate.

Evaluation of Surveillance System Changes to Improve Detection of Disseminated Gonococcal Infections in Virginia, 2018 to 2021

BACKGROUND

Disseminated gonococcal infection (DGI), a complication of untreated gonorrhea, is rarely reported through routine surveillance. We sought to improve local surveillance system capacity to estimate and monitor the incidence of DGI in Virginia.

METHODS

We modified surveillance protocols to identify possible DGI cases using information extracted from gonorrhea case reports and performed provider follow-up using standardized case report forms to confirm DGI diagnosis and collect clinical information. Suspect cases included those with a laboratory report indicating sterile site of specimen collection (e.g., blood, synovial fluid) and/or intravenous (IV) treatment. We performed descriptive analyses to summarize the characteristics of suspect and confirmed DGIs and estimated incidence.

RESULTS

After piloting protocols in 2018 to 2019, we identified 405 suspect DGI cases from 29,294 gonorrhea cases reported in 2020 to 2021 (1.4%). We initiated investigations for 298 (73.6%) of the suspect cases, received provider responses for 105 (25.9%), and confirmed 19 DGI cases (4.7%). Positive laboratory reports from nonmucosal sites were the most reliable predictor of confirmed DGI status, but most were not confirmed as DGI even when provider follow-up was successful. The confirmed and estimated incidence of DGI were 0.06% and 0.22%, respectively. Sixteen (84%) of the confirmed cases were older than 25 years, 3 (16%) were HIV positive, and approximately half were male and non-Hispanic Black. Most (15 [74%]) were hospitalized, and common manifestations included septic arthritis and bacteremia.

CONCLUSIONS

We improved surveillance for DGI in Virginia while incurring minor programmatic costs. Additional efforts to improve the completeness and quality of surveillance data for DGI are needed.

Ten Years of Disseminated Gonococcal Infections in North Carolina: A Review of Cases From a Large Tertiary Care Hospital

BACKGROUND

The detection and reporting of disseminated gonococcal infection (DGI) has been increasing across the United States.

METHODS

We conducted a retrospective chart review of DGI case-patients diagnosed between 2010 and 2019 at a large tertiary care hospital in North Carolina.

RESULTS

We identified 12 DGI case-patients (7 men and 5 women, aged 20 to 44 years), of whom 5 had Neisseria gonorrheae isolated from a sterile site (confirmed), 2 had N. gonorrheae detected at a nonsterile mucosal site and had clinical manifestations consistent with DGI (probable), and 5 did not have N. gonorrheae isolated from any site, but DGI was the most likely diagnosis (suspect). Among the 12 DGI case-patients, the most common manifestation was arthritis or tenosynovitis (n = 11); 1 patient had endocarditis. Half of the patients had significant underlying comorbidities or predisposing factors, including complement deficiency. Eleven of the 12 case-patients were hospitalized, and 4 required surgical intervention.

CONCLUSIONS

This case series highlights the difficulty of making a definitive diagnosis of DGI, which could negatively affect reporting to public health authorities and hinder surveillance efforts to determine the true prevalence of DGI. A high index of suspicion is required, and a full diagnostic workup should be pursued in all cases of suspected DGI.

A Mysterious Case of Left Shoulder Pain in AIDS: A Case Report and Literature Review

Neisseria (N.) gonorrhea is a gram-negative diplococcus and one of the most commonly reported sexually transmitted infections (STIs) in the United States. Disseminated gonococcal infection is a rare but serious complication of N. gonorrhoeae infection that can result in arthritis-dermatitis syndrome or purulent gonococcal arthritis. Co-infection with human immunodeficiency virus (HIV) has been shown to reduce the efficacy of complement recruitment, which may lead to an increased risk of disseminated gonococcal spread. We present a case of a 41-year-old male with concomitant HIV-gonorrhea infection complicated by rare chronic subacute septic arthritis localized to the left shoulder. The patient had a history of HIV, hypertension, and diabetes, and presented with symptoms, including diarrhea, oral thrush, body aches, and fevers. During his hospitalization, the patient developed increasing left shoulder pain, and imaging and joint aspiration revealed N. gonorrhoeae as the causative agent. The patient was treated with appropriate antibiotics and showed improvement. This case highlights the importance of considering disseminated gonococcal infection as a potential complication of N. gonorrhoeae infection, particularly in patients with concomitant HIV infection, and the need for prompt diagnosis and appropriate treatment to prevent complications.

Genomic analysis of 1710 surveillance-based Neisseria gonorrhoeae isolates from the USA in 2019 identifies predominant strain types and chromosomal antimicrobial-resistance determinants

This study characterized high-quality whole-genome sequences of a sentinel, surveillance-based collection of 1710 Neisseria gonorrhoeae (GC) isolates from 2019 collected in the USA as part of the Gonococcal Isolate Surveillance Project (GISP). It aims to provide a detailed report of strain diversity, phylogenetic relationships and resistance determinant profiles associated with reduced susceptibilities to antibiotics of concern. The 1710 isolates represented 164 multilocus sequence types and 21 predominant phylogenetic clades. Common genomic determinants defined most strains' phenotypic, reduced susceptibility to current and historic antibiotics (e.g. bla _TEM plasmid for penicillin, tetM plasmid for tetracycline, gyrA for ciprofloxacin, 23S rRNA and/or mosaic mtr operon for azithromycin, and mosaic penA for cefixime and ceftriaxone). The most predominant phylogenetic clade accounted for 21 % of the isolates, included a majority of the isolates with low-level elevated MICs to azithromycin (2.0 µg ml^-1), carried a mosaic mtr operon and variants in PorB, and showed expansion with respect to data previously reported from 2018. The second largest clade predominantly carried the GyrA S91F variant, was largely ciprofloxacin resistant (MIC ≥1.0 µg ml^-1), and showed significant expansion with respect to 2018. Overall, a low proportion of isolates had medium- to high-level elevated MIC to azithromycin ((≥4.0 µg ml^-1), based on C2611T or A2059G 23S rRNA variants). One isolate carried the penA 60.001 allele resulting in elevated MICs to cefixime and ceftriaxone of 1.0 µg ml^-1. This high-resolution snapshot of genetic profiles of 1710 GC sequences, through a comparison with 2018 data (1479 GC sequences) within the sentinel system, highlights change in proportions and expansion of select GC strains and the associated genetic mechanisms of resistance. The knowledge gained through molecular surveillance may support rapid identification of outbreaks of concern. Continued monitoring may inform public health responses to limit the development and spread of antibiotic-resistant gonorrhoea.

Neisseria gonorrhoeae cervical spine epidural abscess requiring spinal decompression and instrumented fusion

Disseminated gonococcal infection (DGI) is an uncommon complication of Neisseria gonorrhoeae infection, and typically presents with either a triad of tenosynovitis, dermatitis and polyarthralgia, or with extra-axial large joint septic arthritis. Spinal epidural abscess is a rare manifestation of DGI, with only a few previously reported cases, none of which required placement of metalware into the infected space. Here we report a severe case of isolated N. gonorrhoeae cervical spine epidural abscess necessitating surgical source control (C7/T1 laminectomy and debridement) and metalware placement (C6-T2 posterior instrumented fusion). The case was successfully managed by a combination of surgical intervention followed by six weeks of predominantly oral, targeted antimicrobial therapy.

Characterizing the Rise of Disseminated Gonococcal Infections in California, July 2020-July 2021

BACKGROUND

California has experienced an increase in reported cases of disseminated gonococcal infection (DGI). Given significant morbidity associated with DGI and the ability of Neisseria gonorrhoeae to rapidly develop antibiotic resistance, characterization of these cases can inform diagnosis, management, and prevention of DGI.

METHODS

As part of the public health response to increased reports of DGI, we used gonorrhea surveillance data reported to the California Department of Public Health to identify all DGI cases in a geographically-bound region. Standardized case report forms were used to collect epidemiologic risk factors and clinical information obtained from provider/laboratory reports, medical records, and patient interviews.

RESULTS

From 1 July 2020 to 31 July 2021, we identified 149 DGI patients among 63 338 total gonorrhea infections, representing 0.24% of gonorrhea cases. Estimated incidence was 0.47 DGI cases per 100 000 person-years. Mean age of DGI patients was 40 years, and 75 (50%) were cisgender men, of whom only 13 were known to have male partners. Where reported, more than one-third (36%) used methamphetamine and nearly one-quarter (23%) experienced homelessness. Clinically, 61% lacked urogenital, pharyngeal, or rectal symptoms; 2 patients died in the hospital. Among 47 isolates from patients with antimicrobial susceptibility testing (AST) results available, all were susceptible to ceftriaxone and cefixime.

CONCLUSIONS

Most DGI patients lacked urogenital symptoms and were not among populations for which routine gonorrhea screening is currently recommended. Expanding gonorrhea screening might prevent DGI. Cefixime is likely the best option if transitioning from parenteral to oral therapy when AST results are unavailable.

Phylogenomic comparison of Neisseria gonorrhoeae causing disseminated gonococcal infections and uncomplicated gonorrhea in Georgia, United States

Disseminated gonococcal infection (DGI) is a rare complication caused by the systemic dissemination of Neisseria gonorrhoeae (Ng) to normally sterile anatomical sites. Little is known about the genetic diversity of DGI gonococcal strains and how they relate to other gonococcal strains causing uncomplicated mucosal infections. We used whole genome sequencing to characterize DGI isolates (n = 30) collected from a surveillance system in Georgia (GA), USA during 2017-2020 to understand phylogenetic clustering among DGI as well as uncomplicated uro-and-extragenital gonococcal (UGI) isolates (n = 110) collected in Fulton County, GA during 2017-2019. We also investigated the presence or absence of genetic markers related to antimicrobial resistance (AMR) as well as surveyed the genomes for putative virulence genetic factors associated with normal human-serum (NHS) resistance that might facilitate DGI. We found that DGI strains demonstrated significant genetic variability similar to the population structure of isolates causing UGI, with sporadic incidences of geographically clustered DGI strains. DGI isolates contained various AMR markers and genetic mechanisms associated with NHS resistance. DGI isolates had a higher frequency of the porB1A allele compared with UGI (67% vs. 9%, p &lt; 0.0001); however, no single NHS resistance marker was found in all DGI isolates. Continued DGI surveillance with genome-based characterization of DGI isolates is necessary to better understand specific factors that promote systemic dissemination.