Search

A rapid and affordable point-of-care test is a priority for Neisseria gonorrhoeaecontrol. WHO and Foundation for Innovative New Diagnostics (FIND) have a target product profile for a non-molecular N gonorrhoeaerapid 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.

ObjectivesPharyngeal 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.MethodsThis 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.ResultsOverall, 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.ConclusionsThe 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.

Chlamydia trachomatisand Neisseria gonorrhoeaeinfections in the rectum and pharynx are important extragenital reservoirs of infection. Few assays approved by the US Food and Drug Administration are commercially available to diagnose pharyngeal or rectal infections. The current study reports on the analytical performance of the Abbott RealTime CT/NG assay, including the limit of detection, inclusivity, and analytical specificity for C. trachomatisand N. gonorrhoeaein rectal and pharyngeal specimens. The limit of detection was performed using known concentrations of organisms, elementary bodies per milliliter (EB/mL) for C. trachomatisand colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae, in clinical rectal and pharyngeal swab matrices. Inclusivity was performed against 12 serovars of C. trachomatisand seven strains of N. gonorrhoeae. The analytical specificity was performed using 28 different bacteria and viruses. The limit of detection for C. trachomatiswas 2.56 EB/mL in pharyngeal specimens and 12.8 EB/mL in rectal specimens. The limit of detection for N. gonorrhoeaewas 0.0256 CFU/mL for both pharyngeal and rectal specimens. The inclusivity and analytical specificity were 100% for both rectal and pharyngeal specimens. These analytical performance data demonstrate that the Abbott CT/NG RealTime assay is an accurate, sensitive, and specific assay in rectal and pharyngeal specimens, supporting the potential of the assay for detection of rectal and pharyngeal C. trachomatisand N. gonorrhoeaeinfections.

ABSTRACTListeria monocytogenesis a Gram-positive intracellular pathogen that is naturally resistant to lysozyme. Recently, it was shown that peptidoglycan modification by N-deacetylation or O-acetylation confers resistance to lysozyme in various Gram-positive bacteria, including L. monocytogenes. L. monocytogenespeptidoglycan is deacetylated by the action of N-acetylglucosamine deacetylase (Pgd) and acetylated by O-acetylmuramic acid transferase (Oat). We characterized Pgd−, Oat−, and double mutants to determine the specific role of L. monocytogenespeptidoglycan acetylation in conferring lysozyme sensitivity during infection of macrophages and mice. Pgd−and Pgd−Oat−double mutants were attenuated approximately 2 and 3.5 logs, respectively, in vivo. In bone-marrow derived macrophages, the mutants demonstrated intracellular growth defects and increased induction of cytokine transcriptional responses that emanated from a phagosome and the cytosol. Lysozyme-sensitive mutants underwent bacteriolysis in the macrophage cytosol, resulting in AIM2-dependent pyroptosis. Each of the in vitrophenotypes was rescued upon infection of LysM−macrophages. The addition of extracellular lysozyme to LysM−macrophages restored cytokine induction, host cell death, and L. monocytogenesgrowth inhibition. This surprising observation suggests that extracellular lysozyme can access the macrophage cytosol and act on intracellular lysozyme-sensitive bacteria.

Listeria monocytogenes is a Gram-positive intracellular pathogen that is naturally resistant to lysozyme. Recently, it was shown that peptidoglycan modification by N-deacetylation or O-acetylation confers resistance to lysozyme in various Gram-positive bacteria, including L. monocytogenes. L. monocytogenes peptidoglycan is deacetylated by the action of N-acetylglucosamine deacetylase (Pgd) and acetylated by O-acetylmuramic acid transferase (Oat). We characterized Pgd–, Oat–, and double mutants to determine the specific role of L. monocytogenes peptidoglycan acetylation in conferring lysozyme sensitivity during infection of macrophages and mice. Pgd–and Pgd–Oat–double mutants were attenuated approximately 2 and 3.5 logs, respectively, in vivo. In bone-marrow derived macrophages, the mutants demonstrated intracellular growth defects and increased induction of cytokine transcriptional responses that emanated from a phagosome and the cytosol. Lysozyme-sensitive mutants underwent bacteriolysis in the macrophage cytosol, resulting in AIM2-dependent pyroptosis. Each of the in vitro phenotypes was rescued upon infection of LysM–macrophages. The addition of extracellular lysozyme to LysM–macrophages restored cytokine induction, host cell death, and L. monocytogenes growth inhibition. This surprising observation suggests that extracellular lysozyme can access the macrophage cytosol and act on intracellular lysozyme-sensitive bacteria.