Novel lateral flow assay for point-of-care detection of Neisseria gonorrhoeae infection in syndromic management settings: a cross-sectional performance evaluation.

BACKGROUND: A rapid and affordable point-of-care test is a priority for Neisseria gonorrhoeae control. WHO and Foundation for Innovative New Diagnostics (FIND) have a target product profile for a non-molecular N gonorrhoeae rapid point-of-care test that requires a clinical sensitivity of greater than 80% and a specificity over 95% to be considered useful in syndromic management; test turnaround time should be 30 min or under, and the test should cost less than US$3. A novel lateral flow assay (LFA) was developed to achieve that profile. METHODS: In this cross-sectional study we evaluated the performance of the novel N gonorrhoeae lateral flow assay (NG-LFA) at the primary health-care level in South Africa. Male patients with urethral discharge syndrome and female patients with vaginal discharge syndrome were recruited from five primary health-care facilities in the Buffalo City Metropolitan Municipality health district of South Africa. First-void urine specimens and nurse-collected vaginal swabs were tested in-facility with the NG-LFA and Xpert CT/NG PCR assay. N gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed on all LFA positive specimens. FINDINGS: Between March 7, and Sept 19, 2022, we enrolled 200 male patients with urethral discharge and 200 female patients with vaginal discharge. The median age of male patients was 24 years (IQR 21-31 years), and the median age of female patients was 25 years (IQR 21-32 years). In addition, 23 male patients and 12 female patients who presented at the facility with a partner notification slip were enrolled of whom one (4%) and five (42%) were symptomatic, respectively. NG-LFA and Xpert results were available for all participants. In urine specimens, NG-LFA sensitivity was 96·1% (Wilson 95% CI 91·2-98·3; 123 LFA-positive among 128 PCR-positive specimens) and 91·7% in vaginal swab specimens (78·2-97·1; 33 LFA-positive among 36 PCR-positive). The specificity was 97·2% in urine specimens (90·4-99·2; 70 LFA-negative among 72 PCR-negative) and 96·3% in vaginal specimens (92·2-98·3; 158 LFA-negative among 164 PCR-negative). In 156 LFA-positive specimens, NG-MAST showed 93 different sequence types. INTERPRETATION: The novel NG-LFA had excellent clinical sensitivity and specificity in symptomatic male and female patients. The test met the optimal requirement for sensitivity and the minimal requirement for specificity specified in the target product profile. NG-LFA could provide an important tool to optimise clinical management and reduce excess antibiotic use in settings without direct access to laboratory testing. FUNDING: Global Antimicrobial Resistance Innovation Fund (GAMRIF) via FIND and National Institutes of Health.

Machine learning to predict ceftriaxone resistance using single nucleotide polymorphisms within a global database of Neisseria gonorrhoeae genomes.

IMPORTANCE: Antimicrobial resistance in Neisseria gonorrhoeae is an urgent global health issue. The objectives of the study were to use a global collection of 12,936 N. gonorrhoeae genomes from the PathogenWatch database to evaluate different machine learning models to predict ceftriaxone susceptibility/decreased susceptibility using 97 mutations known to be associated with ceftriaxone resistance. We found the random forest classifier model had the highest performance. The analysis also reported the relative contributions of different mutations within the ML model predictions, allowing for the identification of the mutations with the highest importance for ceftriaxone resistance. A machine learning model retrained with the top five mutations performed similarly to the model using all 97 mutations. These results could aid in the development of molecular tests to detect resistance to ceftriaxone in N. gonorrhoeae. Moreover, this approach could be applied to building and evaluating machine learning models for predicting antimicrobial resistance in other pathogens.

Why charging Li-air batteries with current low-voltage mediators is slow and singlet oxygen does not explain degradation.

Although Li-air rechargeable batteries offer higher energy densities than lithium-ion batteries, the insulating Li2O2 formed during discharge hinders rapid, efficient re-charging. Redox mediators are used to facilitate Li2O2 oxidation; however, fast kinetics at a low charging voltage are necessary for practical applications and are yet to be achieved. We investigate the mechanism of Li2O2 oxidation by redox mediators. The rate-limiting step is the outer-sphere one-electron oxidation of Li2O2 to LiO2, which follows Marcus theory. The second step is dominated by LiO2 disproportionation, forming mostly triplet-state O2. The yield of singlet-state O2 depends on the redox potential of the mediator in a way that does not correlate with electrolyte degradation, in contrast to earlier views. Our mechanistic understanding explains why current low-voltage mediators (<+3.3 V) fail to deliver high rates (the maximum rate is at +3.74 V) and suggests important mediator design strategies to deliver sufficiently high rates for fast charging at potentials closer to the thermodynamic potential of Li2O2 oxidation (+2.96 V).

Discovery of a novel sub-lineage of multi-drug resistant Shigella flexneri in Southern California.

Clustered outbreaks of multi-drug resistant (MDR) Shigella are on the rise among men who have sex with men (MSM). Identification of MDR sub-lineages is critical for clinical management and public health interventions. Here, we describe a novel MDR sub-lineage of Shigella flexneri isolated from an MSM patient without a travel history in Southern California. Detailed genomic characterization of this novel strain would serve as a reference to aid monitoring and future outbreak investigation of MDR Shigella among MSM.

Whole-Genome Sequencing to Predict Antimicrobial Susceptibility Profiles in Neisseria gonorrhoeae.

BACKGROUND: Neisseria gonorrhoeae is a major public health problem due to increasing incidence and antimicrobial resistance. Genetic markers of reduced susceptibility have been identified; the extent to which those are representative of global antimicrobial resistance is unknown. We evaluated the performance of whole-genome sequencing (WGS) used to predict susceptibility to ciprofloxacin and other antimicrobials using a global collection of N. gonorrhoeae isolates. METHODS: Susceptibility testing of common antimicrobials and the recently developed zolifodacin was performed using agar dilution to determine minimum inhibitory concentrations (MICs). We identified resistance alleles at loci known to contribute to antimicrobial resistance in N. gonorrhoeae from WGS data. We tested the ability of each locus to predict antimicrobial susceptibility. RESULTS: A total of 481 N. gonorrhoeae isolates, collected between 2004 and 2019 and making up 457 unique genomes, were sourced from 5 countries. All isolates with demonstrated susceptibility to ciprofloxacin (MIC ≤0.06 µg/mL) had a wild-type gyrA codon 91. Multilocus approaches were needed to predict susceptibility to other antimicrobials. All isolates were susceptible to zoliflodacin, defined by an MIC ≤0.25 µg/mL. CONCLUSIONS: Single marker prediction can be used to inform ciprofloxacin treatment of N. gonorrhoeae infection. A combination of molecular markers may be needed to determine susceptibility for other antimicrobials.

A Position Statement on Mpox as a Sexually Transmitted Disease.

The global outbreak of mpox virus constituted an international public health emergency. Reports have highlighted (1) a temporal association between sexual activity and mpox, (2) an association between specific sexual practices and location of lesion development, (3) a high frequency of sexual practices conferring risk for other sexually transmitted infections among cases of mpox, (4) that mpox virus can be isolated from sexual fluids, (4) that isolated virus is infectious, and (5) a high frequency of anogenital lesions prior to disease dissemination suggesting direct inoculation during sexual activities. Finally, a growing body of evidence suggests that sexual transmission is the predominant mode of transmission for mpox virus. We therefore conclude that mpox is a sexually transmitted disease. Labeling it as such will help focus public health interventions, such as vaccinations, testing, and treatment, as well as facilitate focused awareness and education programs toward behavioral modifications to reduce exposures.

Prevalence and Factors Associated With Antigen Test Positivity Following SARS-CoV-2 Infection Among Health Care Workers in Los Angeles.

Surges of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among health care workers (HCWs) have led to critical staffing shortages. From January 4 to February 4, 2022, we implemented a return-to-work antigen testing program for HCWs, and 870 HCWs participated. Antigen test positivity was 60.5% for those ≤5 days from symptom onset or positive polymerase chain reaction (PCR), and 47.4% were positive at day 7. Antigen positivity was associated with receiving a booster vaccination and being ≤6 days from symptom onset or PCR test, but not age or a symptomatic infection. Rapid antigen testing can be a useful tool to guide return-to-work and isolation precautions for HCWs following infection.

Endofungal Mycetohabitans rhizoxinica Bacteremia Associated with Rhizopus microsporus Respiratory Tract Infection.

We report Mycetohabitans rhizoxinica bacteremia in a 65-year-old woman in California, USA, who was undergoing chimeric antigen receptor T-cell therapy for multiple myeloma. Acute brain infarction and pneumonia developed; Rhizopus microsporus mold was isolated from tracheal suction. Whole-genome sequencing confirmed bacteria in blood as genetically identical to endofungal bacteria inside the mold.

Resistance-Guided Therapy for Neisseria gonorrhoeae.

Antimicrobial-resistant Neisseria gonorrhoeae infections are a threat to public health. Novel strategies for combating such resistance include the development of molecular assays to facilitate real-time prediction of antimicrobial susceptibility. Resistance to ciprofloxacin is determined by the presence of a single mutation at codon 91 of the gyrase A gene; molecular assays to guide therapy are commercially available. Resistance to cefixime is conferred via 1 of 6 critical mutations in either the mosaic penA gene or specific loci in the nonmosaic region. Resistance to ceftriaxone is conferred through mutations in 1 of 4 genes: penA, ponA, penB, and mtr; however, the ability to predict reduced susceptibility based on those genes varies by geographic region. Here, we highlight the work done toward the development of 3 such assays for ciprofloxacin, cefixime, and ceftriaxone, discuss the status of our current understanding and ongoing challenges, and suggest future directions.

Prevalence, Anatomic Distribution, and Correlates of Chlamydia trachomatis and Neisseria gonorrhoeae Infections Among a Cohort of Men Who Have Sex With Men in Hanoi, Vietnam.

BACKGROUND: Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) disproportionately affect men who have sex with men (MSM). Data on the prevalence, anatomical distribution, and correlates of NG and CT infections among MSM in Vietnam are limited. METHODS: Between July 2017 and April 2019, MSM 16 years or older without HIV were enrolled into an observational cohort study. Baseline data, including sociodemographics, sexual behavior, and HIV status, were collected. Testing for NG and CT were performed on urine, rectal, and pharyngeal specimens. Multivariate logistic regression models identified factors associated with NG and CT infections at baseline. RESULTS: In total, 1489 participants underwent NG/CT testing. The median age was 22 years (interquartile range, 20-26 years). There were 424 (28.5%) NG or CT infections: 322 (21.6%) with CT and 173 (11.6%) with NG. Rectal infections were most common for CT (73.9%), whereas pharyngeal infections were most common for NG (70.5%). Independent risk factors for CT or NG infection included ≥2 sex partners in the prior month (adjusted odds ratio [aOR], 2.04; 95% confidence interval [CI], 1.44-2.91), condomless anal sex (aOR, 1.44; 95% CI, 1.12-1.86), and meeting sex partners online (aOR, 1.35; 95% CI, 1.03-1.76). Recent genitourinary or rectal symptoms were not associated with infections. CONCLUSIONS: The overall and extragenital prevalences of NG and CT infections were high within this sample of young MSM without HIV in Hanoi. Testing limited to urethral specimens would have missed nearly three-quarters of CT and NG infections, supporting the need for routine testing at multiple anatomic sites.

Reliability of Genetic Alterations in Predicting Ceftriaxone Resistance in Neisseria gonorrhoeae Globally.

Antimicrobial resistance in N. gonorrhoeae is increasing globally, and ceftriaxone is the recommended treatment for empirical therapy in most settings. Developing molecular assays to detect decreased ceftriaxone susceptibility is critical. Using PathogenWatch, a public database of N. gonorrhoeae genomes, antibiotic susceptibility data and DNA sequences of different genes associated with ceftriaxone resistance were extracted. That information was used to determine the sensitivity and specificity of different molecular markers and algorithms to predict decreased susceptibility to ceftriaxone. A total of 12,943 N. gonorrhoeae genomes were extracted from the PathogenWatch database, of which 9,540 genomes were used in the analysis. The sensitivity and specificity of specific molecular markers and algorithms were largely consistent with prior reports. Small variation (<10%) in either sensitivity or specificity occurred. Certain algorithms using different molecular markers at various prevalence of decreased ceftriaxone susceptibility identified a potentially clinically useful range of positive and negative predictive values. We validated previously described mutations and algorithms in a large public database containing a global collection of N. gonorrhoeae genomes. Certain mutations and algorithms resulted in sensitivity and specificity values consistent with those of prior studies. Further research is needed to integrate these markers and algorithms into the development of molecular assays to predict decreased ceftriaxone susceptibility. IMPORTANCE Antimicrobial resistance in Neisseria gonorrhoeae (N. gonorrhoeae), the causative agent of gonorrhea, is rising globally. Ceftriaxone is the last remaining antibiotic for empirical treatment of gonorrhea. Developing molecular tests to predict ceftriaxone resistance can help to improve detection and surveillance of ceftriaxone resistance. Here, we utilized PathogenWatch, a public global online database of N. gonorrhoeae genomes, to evaluate different genetic markers in predicting decreased susceptibility to ceftriaxone. We compiled MICs for ceftriaxone from the PathogenWatch database and used a computational approach to extract all the genetic markers from the genomic data. We determined the sensitivity and specificity for predicting decreased ceftriaxone susceptibility among several combinations of genetic markers. We identified several combinations of genetic markers with high predictive values for decreased susceptibility to ceftriaxone. These combinations of genetic markers might be promising candidates for future molecular tests to predict ceftriaxone resistance.

High proportions of rectal and pharyngeal chlamydia and gonorrhoea cases among cisgender men are missed using current CDC screening recommendations.

OBJECTIVES: Pharyngeal and rectal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are often undiagnosed due to their asymptomatic nature. This study aims to determine (1) the prevalence of CT/NG infections by anatomical site among cisgender men; (2) the proportion of missed CT/NG rectal/pharyngeal infections if urogenital testing alone was performed or screening depended on self-reported behaviour alone; and (3) the predictive probability of self-reported behaviours for rectal CT/NG. METHODS: This cross-sectional study used electronic health records collected at a sexual health clinic in Los Angeles from 18 November 2018 until 28 February 2020. The included patients were ≥18 years of age cisgender men who received CT/NG testing at least once during the study period. We calculated the proportion of missed pharyngeal/rectal CT/NG infections if only urogenital testing had been done and if testing was based only on self-reported anal sex. Separately, we ran logistic regressions for predictive probability of self-reported anal sex on CT/NG rectal infections. RESULTS: Overall, there were 13 476 unique patients with 26 579 visits. The prevalence of any extragenital CT/NG infection was 37.28%. Over 80% rectal/pharyngeal CT cases and over 65% rectal/pharyngeal NG cases would be missed if urogenital testing alone was performed. Likewise, over 35% rectal CT/NG cases would be missed had testing relied on self-reported sexual behaviours alone. CONCLUSIONS: The proportion of missed rectal and pharyngeal CT/NG infections is high. Our data from a sexual health clinic lend support to three-site opt-out testing for cisgender men attending a sexual health/Lesbian, Gay, Bisexual, Transgender, Queer/Questioning (LGBTQ+) specialty clinic regardless of their sexual orientation or reported sexual behaviours.

Diagnostic Tests for Detecting Chlamydia trachomatis and Neisseria gonorrhoeae in Rectal and Pharyngeal Specimens.

Chlamydia trachomatis and Neisseria gonorrhoeae are two of the most often reported bacterial infections in the United States. The rectum and oropharynx are important anatomic sites of infection and can contribute to ongoing transmission. Nucleic acid amplification tests (NAATs) are the mainstays for the detection of C. trachomatis and N. gonorrhoeae infections owing to their high sensitivity and specificity. Several NAATs have been evaluated for testing in rectal and pharyngeal infections. A few assays recently received clearance by the Food and Drug Administration, including one point-of-care test. Those assays can be used for testing in symptomatic individuals, as well as for asymptomatic screening in certain patient populations. Routine screening for C. trachomatis in pharyngeal specimens is not recommended by the Centers for Disease Control and Prevention, though it is often performed due to the use of multiplex assays. While expanding the types of settings for screening and using self-collected rectal and pharyngeal specimens can help to increase access and uptake of testing, additional research is needed to determine the potential benefits and costs associated with increased screening for rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections on a population level.

Adolescents may accurately self-collect pharyngeal and rectal clinical specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae infection.

BACKGROUND: The COVID-19 pandemic illuminated the benefits of telemedicine. Self-collected specimens are a promising alternative to clinician-collected specimens when in-person testing is not feasible. In this study, we assessed the adequacy of self-collected pharyngeal and rectal specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae among individuals undergoing chlamydia and gonorrhea screening. METHODS: We used data from a large cohort study that included male and female adolescents between the ages of 12-24 years. We considered self-collected specimens adequate for clinical use if the human synthase gene (a control target of the assay) was detected in the specimen. RESULTS: In total, 2,458 specimens were included in the analysis. The human synthase gene was detected in 99.2% (2,439/2,458) of all self-collected specimens, 99.5% (1,108/1,114) of the pharyngeal specimens, and 99.0% (1,331/1,344) of the rectal specimens. CONCLUSION: Self-collected pharyngeal and rectal specimens demonstrated a very high proportion of human gene presence, suggesting that self-collection was accurate. A limitation of this study is that the sample adequacy control detects the presence or absence of the human hydroxymethylbilane synthase gene, but it does not indicate the specific anatomic origin of the human hydroxymethylbilane synthase gene. Self-collected specimens may be an appropriate alternative to clinician-collected specimens.

Using a public database of Neisseria gonorrhoeae genomes to detect mutations associated with zoliflodacin resistance.

BACKGROUND: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is an urgent global health threat. Zoliflodacin is a novel antibiotic undergoing clinical trials for the treatment of gonorrhoea. While there are limited data regarding zoliflodacin resistance in N. gonorrhoeae, three amino acid mutations have been associated with increased MICs of zoliflodacin. OBJECTIVES: To determine the prevalence of three amino acid mutations associated with zoliflodacin resistance within a large, public database of nearly 13 000 N. gonorrhoeae genomes. METHODS: PathogenWatch is an online genomic epidemiology platform with a public database of N. gonorrhoeae genomes. That database was used to extract gyrB sequence data and a Basic Local Alignment Search Tool (BLAST) search was performed to identify any of the three amino acid mutations in GyrB that are associated with increased zoliflodacin MICs: D429N, K450N or K450T. As a control for the search methodology, all GyrA sequences were also extracted and S91F mutations were identified and compared with the PathogenWatch database. RESULTS: In total, 12 493 N. gonorrhoeae genomes from the PathogenWatch database were included. Among those genomes, none was identified that harboured any of the three mutations associated with increased zoliflodacin MICs. One genome was identified to have a mutation at position 429 in GyrB (D429V). CONCLUSIONS: The findings suggest that the prevalence of the three mutations associated with zoliflodacin resistance in N. gonorrhoeae is very low. However, further research into the mechanisms of zoliflodacin resistance in N. gonorrhoeae is needed. Genomic epidemiology platforms like PathogenWatch can be used to enhance the global surveillance of AMR.