Usability of a novel lateral flow assay for the point-of-care detection of Neisseria gonorrhoeae : a qualitative time-series assessment among healthcare workers in South Africa

DATA AVAILABILITY STATEMENT : The dataset for the System Usability Scale (SUS) has been uploaded to the Open Science Framework data repository. The identifier for this dataset is DOI 10.17605/OSF.IO/ EFVHS. The qualitative data are not publicly available due to privacy or ethical restrictions as ensured by participant informed consent and South Africa’s protection of personal information act (POPIA). The relevant contact for any data inquiries and access upon reasonable request is: Freedom Mukomana Data Manager, Foundation for Professional DevelopmentSUPPORTING INFORMATION : FILE S1. FIND NG-LFA testing and reader- set up instructions (QuickCards). FILE S2. Study participation flow for time series assessment: SUS surveys and IDIs.Accurate and user-friendly rapid point-of-care diagnostic tests (POCT) are needed to optimize treatment of Neisseria gonorrhoeae, especially in low-resource settings where syndromic management is the standard of care for sexually transmitted infections. This study aimed to assess the acceptability and usability of a novel lateral flow assay and portable reader for the point-of-care detection of N. gonorrhoeae infection (NG-LFA). This mixedmethods study was conducted as part of a diagnostic performance and usability evaluation of a prototype NG-LFA for detection of N. gonorrhoeae in symptomatic men and women at primary healthcare facilities in the Buffalo City Metro, South Africa. The Standardized System Usability Scale (SUS) was administered, and in-depth interviews were conducted among healthcare professionals (HCPs) and fieldworkers (FWs) at pre-implementation, initial use and 3- and 6-month study implementation to assess user expectations, practical experience, and future implementation considerations for the NG-LFA. Data collection and analysis was guided by the Health Technology Adoption Framework, including new health technology attributes, learnability, satisfaction, and suitability. The framework was adapted to include perceived durability. A total of 21 HCPs and FWs were trained on the NG-LFA use. SUS scores showed good to excellent acceptability ranging from 78.8–90.6 mean scores between HCPs and FWs across study time points. All transcripts were coded using Dedoose and qualitative findings were organized by learnability, satisfaction, suitability, and durability domains. Usability themes are described for each time point. Initial insecurity dissipated and specimen processing dexterity with novel POCT technology was perfected over time especially amongst FWs through practical learning and easy-to-use instructions (learnability). Participants experienced both positive and negative test results, yielding perceived accuracy and minimal testing challenges overall (satisfaction). By 3- and 6-month use, both HCPs and FWs found the NG-LFA convenient to use in primary health care facilities often faced with space constraints and outlined perceived benefits for patients (suitability and durability). Findings show that the NG-LFA device is acceptable and usable even amongst paraprofessionals. High SUS scores and qualitative findings demonstrate high learnability, ease-of-use and suitability that provide valuable information for first-step scale-up requirements at primary healthcare level. Minor prototype adjustments would enhance robustness and durability aspects.The performance evaluation was funded by a sub-award from the Global Antimicrobial Resistance Innovation Fund (GAMRIF) via FIND. (Funder website: https://www.gov.uk/government/groups/theglobal- amr-innovation-fund).https://journals.plos.org/plosone/am2024Medical MicrobiologySDG-03:Good heatlh and well-bein

Evaluation of a Novel Culture System for Rapid Pathogen Identification and Detection of Cephalosporin Resistance in Neonatal Gram-negative Sepsis at a Tertiary Referral Unit in Harare, Zimbabwe.

BACKGROUND: Neonatal sepsis accounts for a large proportion of neonatal deaths in sub-Saharan Africa. The lack of access to diagnostic testing and excessively long turnaround times to result contributes to delays in sepsis identification and initiation of appropriate treatment. This study aims to evaluate the novel InTrays COLOREX Screen and extended-spectrum beta-lactamase for rapid identification of bacterial pathogens causing sepsis and detection of resistance. METHODS: Neonates with suspected sepsis admitted to the Harare Central Hospital were prospectively enrolled. One blood culture was collected and incubated using the BacT/ALERT automated system. Positive blood cultures with potential pathogens identified by Gram stain were inoculated on the InTray COLOREX Screen and extended-spectrum beta-lactamase culture plates. RESULTS: A total of 216 neonates with suspected sepsis were recruited. Pathogens were isolated from blood cultures in 56 (25.9%) neonates of which 54 were Klebsiella pneumoniae. All K. pneumoniae were resistant to ceftriaxone and 53 (98%) were resistant to gentamicin. Sensitivity and specificity for ceftriaxone-resistant K. pneumoniae detection using InTrays were 100%. InTrays results were interpretable as early as 5-10 hours (median 7 hours, interquartile range 7-7) post blood culture positivity enabling rapid identification and notification of result and leading to a 60% reduction in time to result from blood culture collection. CONCLUSIONS: This study shows that the implementation of a novel culture method was feasible and reduced turnaround times for results by 60% compared with standard microbiologic techniques. An impact on patient outcomes and cost-effectiveness of this method needs to be demonstrated

Evaluation of the InTray and Compact Dry culture systems for the diagnosis of urinary tract infections in patients presenting to primary health clinics in Harare, Zimbabwe.

Antimicrobial resistance surveillance data is lacking from many resource-limited settings mainly due to limited laboratory testing. Novel culture systems may address some of the limitations of conventional culture media and expand the availability of microbiology services. The aims of this study were to evaluate the performance of InTray COLOREX Screen/ESBL and Compact Dry for the detection of uropathogens and of extended-spectrum beta-lactamase (ESBL)-producing organisms from urine samples. Urines samples were collected from patients presenting with symptoms of urinary tract infection to primary care clinics in Harare. Performance of the InTray COLOREX Screen, ESBL and Compact Dry chromogenic media were compared to the reference of culture using Brilliance UTI agar and conventional antimicrobial susceptibility testing. A total of 414 samples were included in the analysis. Of the included samples, 98 were positive on Brilliance UTI agar and 83 grew Enterobacterales. The sensitivities and specificities for Enterobacterales were 89.2% (95% CI 80.4-94.9) and 98.2% (95% CI 96.1-99.3) for InTray Screen and 95.2% (95% CI 88.1-98.7) and 99.7% (95% CI 98.3-100) for Compact Dry. Extended-spectrum beta-lactamases were present in 22 isolates from the Brilliance UTI agar. The sensitivity of the InTray COLOREX ESBL culture plates for the detection of ESBL-producing organisms was 95.5% (95% CI 77.2-99.9) and specificity was 99.5% (95% CI 98.2-99.9%). Our findings show good performance of the novel culture systems for the detection of uropathogens and ESBL-producing organisms. Both systems have several advantages over conventional media and have the potential to expand and decentralize laboratory testing

Distribution of the ribosome associated endonuclease Rae1 and the potential role of conserved amino acids in codon recognition

We recently identified a novel ribonuclease in Bacillus subtilis called Rae1 that cleaves mRNAs in a translation-dependent manner. Rae1 is a member of the NYN/PIN family of ribonucleases and is highly conserved in the Firmicutes, the Cyanobacteria and the chloroplasts of photosynthetic algae and plants. We have proposed a model in which Rae1 enters the A-site of ribosomes that are paused following translation of certain sequences that are still ill-defined. In the only case identified thus far, Rae1 cleaves between a conserved glutamate and lysine codon during translation of a short peptide called S1025. Certain other codons are also tolerated on either side of the cleavage site, but these are recognized less efficiently. The model of Rae1 docked in the A-site allows us to make predictions about which conserved residues may be important for recognition of mRNA, the tRNA in the adjacent P-site and binding to the 50S ribosome subunit

Structural studies of Mycobacterium tuberculosis DprE1 interacting with its inhabitors

The flavoenzyme DprEl catalyses a crucial step in arabinan production for cell wall biosynthesis in Mycobacterium tuberculosis and is a highly vulnerable drug target. It was first discovered using benzothiazinones (BTZ): exquisitely potent bactericidal agents that are being developed as drugs to treat tuberculosis. Subsequently, many compounds with diverse scaffolds were found to act as either covalent or noncovalent DprEl inhibitors. Covalent inhibitors, like the BTZ, are all nitroaromatic compounds that serve as suicide substrates after DprEl-mediated nitroreduction. Here, we describe how high resolution structures of DprEl, alone and in complex with various ligands, explain enzyme activity and inhibition

Polarly Localized EccE(1) Is Required for ESX-1 Function and Stabilization of ESX-1 Membrane Proteins in Mycobacterium tuberculosis

Mycobacterium tuberculosis is a slow-growing intracellular bacterium with the ability to induce host cell death and persist indefinitely in the human body. This pathogen uses the specialized ESX-1 secretion system to secrete virulence factors and potent immunogenic effectors required for disease progression. ESX-1 is a multisubunit apparatus with a membrane complex that is predicted to form a channel in the cytoplasmic membrane. In M. tuberculosis this complex is composed of five membrane proteins: EccB(1), EccCa(1), EccCb(1), EccD(1), and EccE(1). In this study, we have characterized the membrane component EccE(1) and found that deletion of eccE(1) lowers the levels of EccB(1), EccCa(1), and EccD(1), thereby abolishing ESX-1 secretion and attenuating M. tuberculosis ex vivo. Surprisingly, secretion of EspB was not affected by loss of EccE(1). Furthermore, EccE(1) was found to be a membrane- and cell wall-associated protein that needs the presence of other ESX-1 components to assemble into a stable complex at the poles of M. tuberculosis. Overall, this investigation provides new insights into the role of EccE(1) and its localization in M. tuberculosis.IMPORTANCE Tuberculosis (TB), the world's leading cause of death of humans from an infectious disease, is caused by the intracellular bacterium Mycobacterium tuberculosis. The development of successful strategies to control TB requires better understanding of the complex interactions between the pathogen and the human host. We investigated the contribution of EccE(1), a membrane protein, to the function of the ESX-1 secretion system, the major virulence determinant of M. tuberculosis. By combining genetic analysis of selected mutants with eukaryotic cell biology and proteomics, we demonstrate that EccE(1) is critical for ESX-1 function, secretion of effector proteins, and pathogenesis. Our research improves knowledge of the molecular basis of M. tuberculosis virulence and enhances our understanding of pathogenesis

Structure-Based Drug Design and Characterization of Sulfonyl-Piperazine Benzothiazinone Inhibitors of DprE1 from Mycobacterium tuberculosis

Macozinone (MCZ) is a tuberculosis (TB) drug candidate that specifically targets the essential flavoenzyme DprE1, thereby blocking synthesis of the cell wall precursor decaprenyl phosphoarabinose (DPA) and provoking lysis of Mycobacterium tuberculosis. As part of the MCZ backup program, we exploited structure-guided drug design to produce a new series of sulfone-containing derivatives, 2-sulfonylpiperazin 8-nitro 6-trifluoromethyl 1,3-benzothiazin-4-one, or sPBTZ. These compounds are less active than MCZ but have a better solubility profile, and some derivatives display enhanced stability in microsomal assays. DprE1 was efficiently inhibited by sPBTZ, and covalent adducts with the active-site cysteine residue (C387) were formed. However, despite the H-bonding potential of the sulfone group, no additional bonds were seen in the crystal structure of the sPBTZ-DprE1 complex with compound 11326127 compared to MCZ. Compound 11626091, the most advanced sPBTZ, displayed good antitubercular activity in the murine model of chronic TB but was less effective than MCZ. Nonetheless, further testing of this MCZ backup compound is warranted as part of combination treatment with other TB drugs

Rae1/YacP, a new endoribonuclease involved in ribosome-dependent mRNA decay in Bacillus subtilis

The PIN domain plays a central role in cellular RNA biology and is involved in processes as diverse as rRNA maturation, mRNA decay and telomerase function. Here, we solve the crystal structure of the Rae1 (YacP) protein of Bacillus subtilis, a founding member of the NYN (Nedd4-BP1/YacP nuclease) subfamily of PIN domain proteins, and identify potential substrates in vivo. Unexpectedly, degradation of a characterised target mRNA was completely dependent on both its translation and reading frame. We provide evidence that Rae1 associates with the B. subtilis ribosome and cleaves between specific codons of this mRNA in vivo. Critically, we also demonstrate translation-dependent Rae1 cleavage of this substrate in a purified translation assay in vitro. Multiple lines of evidence converge to suggest that Rae1 is an A-site endoribonuclease. We present a docking model of Rae1 bound to the B. subtilis ribosomal A-site that is consistent with this hypothesis and show that Rae1 cleaves optimally immediately upstream of a lysine codon (AAA or AAG) in vivo

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

Structure of EspB, a secreted substrate of the ESX-1 secretion system of Mycobacterium tuberculosis

Mycobacterium tuberculosis secretes multiple virulence factors during infection via the general Sec and Tat pathways, and via specialized ESX secretion systems, also referred to as type VII secretion systems. The ESX-1 secretion system is an important virulence determinant because deletion of ESX-1 leads to attenuation of M. tuberculosis. ESX-1 secreted protein B (EspB) contains putative PE (Pro-Glu) and PPE (Pro-Pro-Glu) domains, and a C-terminal domain, which is processed by MycP(1) protease during secretion. We determined the crystal structure of PE-PPE domains of EspB, which represents an all-helical, elongated molecule closely resembling the structure of the PE25-PPE41 heterodimer despite limited sequence similarity. Also, we determined the structure of full-length EspB, which does not have interpretable electron density for the C-terminal domain confirming that it is largely disordered. Comparative analysis of EspB in cell lysate and culture filtrates of M. tuberculosis revealed that mature secreted EspB forms oligomers. Electron microscopy analysis showed that the N-terminal fragment of EspB forms donut-shaped particles. These data provide a rationale for the future investigation of EspB's role in M. tuberculosis pathogenesis. (C) 2015 Elsevier Inc. All rights reserved