SARS-CoV-2 immunoassays in a predominantly vaccinated population: Performances and qualitative agreements obtained with two analytical approaches and four immunoassays.

BACKGROUND AND OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurveys are typically analysed by applying a fixed threshold for seropositivity ('conventional approach'). However, this approach underestimates the seroprevalence of anti-nucleocapsid (N) in vaccinated individuals-who often exhibit a difficult-to-detect anti-N response. This limitation is compounded by delays between the onset of infection and sample collection. To address this issue, we compared the performance of four immunoassays using a new analytical approach ('ratio-based approach'), which determines seropositivity based on an increase in anti-N levels. MATERIALS AND METHODS: Two groups of plasma donors and four immunoassays (Elecsys total anti-N, VITROS total anti-N, Architect anti-N Immunoglobulin G (IgG) and in-house total anti-N) were evaluated. First-group donors (N = 145) had one positive SARS-CoV-2 polymerase chain reaction (PCR) test result and had made two plasma donations, including one before and one after the PCR test (median = 27 days post-PCR). Second-group donors (N = 100) had made two plasma donations early in the Omicron wave. RESULTS: Among first-group donors (97.9% vaccinated), sensitivity estimates ranged from 60.0% to 89.0% with the conventional approach, compared with 94.5% to 98.6% with the ratio-based approach. Among second-group donors, Fleiss's κ ranged from 0.56 to 0.83 with the conventional approach, compared with 0.90 to 1.00 with the ratio-based approach. CONCLUSION: With the conventional approach, the sensitivity of four immunoassays-measured in a predominantly vaccinated population based on samples collected ~1 month after a positive test result-fell below regulatory agencies requirement of ≥95%. The ratio-based approach significantly improved the sensitivities and qualitative agreement among immunoassays, to the point where all would meet this requirement.

XyloFUNS: Xylocaine to freeze during unpleasant nasopharyngeal swabs in children-a randomized controlled trial.

Objectives: To evaluate the efficacy of intranasal vaporized lidocaine in reducing pain for children undergoing a nasopharyngeal (NP) swab in the Emergency Department (ED). Study Design: A randomized blinded clinical trial was conducted in a paediatric ED. Both participants and the researcher evaluating the primary outcome were blinded. Children aged 6 to 17 years old requiring a NP swab were eligible. Participants were randomly allocated to receive intranasal lidocaine or a sham treatment prior to their NP swab. The primary outcome measure was pain during the swab as assessed by the visual analog scale. Secondary outcome measures were pain using the verbal numeric rating scale, fear using the children fear scale, and adverse effects of the intervention. Results: Eighty-eight participants were enrolled-45 in the lidocaine group and 43 controls. The mean visual analog scale scores for pain were 46 mm in the lidocaine group and 53 mm in the control group (mean difference 7 mm; 95% CI: -5 to 19 mm). No serious adverse events were observed. Conclusions: Intranasal lidocaine administered prior to NP swabs in the ED failed to show an improvement in pain scores for school-aged children and youth.

Multicenter Evaluation of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy-Based Method for Rapid Identification of Clinically Relevant Yeasts.

Fourier transform infrared (FTIR) spectroscopy has demonstrated applicability as a reagent-free whole-organism fingerprinting technique for both microbial identification and strain typing. For routine application of this technique in microbiology laboratories, acquisition of FTIR spectra in the attenuated total reflectance (ATR) mode simplifies the FTIR spectroscopy workflow, providing results within minutes after initial culture without prior sample preparation. In our previous central work, 99.7% correct species identification of clinically relevant yeasts was achieved by employing an ATR-FTIR-based method and spectral database developed by our group. In this study, ATR-FTIR spectrometers were placed in 6 clinical microbiology laboratories over a 16-month period and were used to collect spectra of routine yeast isolates for on-site identification to the species level. The identification results were compared to those obtained from conventional biochemical tests and/or matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Isolates producing discordant results were reanalyzed by routine identification methods, ATR-FTIR spectroscopy, and PCR gene sequencing of the D1/D2 and internal transcribed spacer (ITS) regions. Among the 573 routine clinical yeast isolates collected and identified by the ATR-FTIR-based method, 564 isolates (98.4%) were correctly identified at the species level, while the remaining isolates were inconclusive with no misidentifications. Due to the low prevalence of Candida auris in routine isolates, additional randomly selected C. auris (n = 24) isolates were obtained for evaluation and resulted in 100% correct identification. Overall, the data obtained in our multicenter evaluation study using multiple spectrometers and system operators indicate that ATR-FTIR spectroscopy is a reliable, cost-effective yeast identification technique that provides accurate and timely (∼3 min/sample) species identification promptly after the initial culture.

Natural spring water gargle and direct RT-PCR for the diagnosis of COVID-19 (COVID-SPRING study).

BACKGROUND: Nasopharyngeal swab has long been considered the specimen of choice for the diagnosis of respiratory viral infections, including SARS-CoV-2 infection, but it suffers from several drawbacks: its discomfort limits screening acceptability, and it is vulnerable to shortages in both specialized materials and trained healthcare workers in the context of a pandemic. METHODS: We prospectively compared natural spring water gargle to combined oro-nasopharyngeal swab (ONPS) for the diagnosis of coronavirus disease 2019 (COVID-19) in paired clinical specimens (1005 ONPS and 1005 gargles) collected from 987 unique early symptomatic as well as asymptomatic individuals from the community. RESULTS: Using a direct RT-PCR method with the Allplex™ 2019-nCoV Assay (Seegene), the clinical sensitivity of the gargle was 95.3% (95% confidence interval [CI], 90.2 - 98.3%), similar to the sensitivity of the ONPS (93.8%; 95% CI, 88.2 - 97.3%), despite significantly lower viral RNA concentration in gargles, as reflected by higher cycle threshold values. No single specimen type detected all COVID-19 cases. SARS-CoV-2 RNA was stable in gargles at room temperature for at least 7 days. CONCLUSION: The simplicity of this sampling method coupled with the accessibility of spring water are clear advantages in a pandemic situation where testing frequency, turnaround time and shortage of consumables and trained staff are critical elements.

Oropharyngeal Carriage of Kingella kingae and Transient Synovitis of the Hip in Young Children: A Case-control Study.

BACKGROUND: Transient synovitis of the hip affects mostly preschool children, and its etiology is unknown. Kingella kingae has been identified recently as a common etiologic agent of osteoarticular infections (OAI) in young children and could potentially be associated to transient synovitis of the hip. The main objective of this study was to evaluate the association between transient synovitis of the hip and oropharyngeal carriage of K. kingae among preschool children. METHODS: This was a prospective case-control study conducted at a tertiary care pediatric emergency department. Cases were children between 6 and 71 months of ages with a diagnosis of transient synovitis of the hip. For each transient synovitis case, an age-matched control was recruited among children presenting for a trauma. A second control group included children with any OAI. The independent variable was the presence of oropharyngeal K. kingae identified by a specific polymerase chain reaction assay. The primary analysis was the association between oropharyngeal K. kingae carriage and final diagnosis. RESULTS: A total of 73 children were included in the study. Among them, 25 had a transient synovitis, 16 an OAI, and 22 controls. Baseline demographics were similar between the groups. There was no difference in oropharyngeal carriage of K. kingae for children with transient synovitis (5/25; 0.20) in comparison to controls (3/22; 0.14), while it was higher for children with OAI (10/16; 0.63). CONCLUSIONS: There is no association between oropharyngeal K. kingae and transient synovitis of the hip among preschool children.

Chronic suppurative otomastoiditis due to nontuberculous mycobacteria: A case series.

INTRODUCTION: Eight new cases of chronic otomastoiditis due to nontuberculous mycobacteria were reported at Center Hospitalier Universitaire Sainte-Justine (CHUSJ) between 2008 and 2018. In the literature, only 89 cases have been described since 1972. This case series aims to define the clinical presentation, infectious pathogens, as well as diagnostic and therapeutic means employed in cases of nontuberculous mycobacteria otitis media encountered in our tertiary pediatric reference center. METHODS: All cases of otitis media caused by nontuberculous mycobacteria diagnosed at Sainte-Justine between 2008 and 2018 were reviewed. Species identification was retrieved from the Laboratoire de Santé Publique du Québec, Quebec's provincial public health and reference laboratory. RESULTS: All 8 cases occurred in immunocompetent children. Clinical features on presentation were chronic tympanostomy tube otorrhea with abundant granulation tissue in 7 cases. CT scan demonstrated coalescent mastoiditis in 3 cases. The median delay between initial presentation and identification of nontuberculous mycobacteria was 81 days. Seven patients had a Mycobacterium (M.) abscessus complex infection. Treatment consisted of weekly microscopic granulation debridement, a combined systemic antibiotic therapy for an average duration of 21 weeks, as well as instillation of boric acid into the middle ear. While 3 cases required at least one mastoidectomy, 2 cases were treated only medically. CONCLUSION: Nontuberculous mycobacteria otitis media is a rare clinical entity, for which high clinical suspicion and specific microbiological analyses could minimize diagnostic delay. The use of boric acid as a desiccating agent may allow for a better local control.

Identification of Candida auris by Use of the Updated Vitek 2 Yeast Identification System, Version 8.01: a Multilaboratory Evaluation Study.

Candida auris is an emerging multidrug-resistant yeast that has been systematically incorrectly identified by phenotypic methods in clinical microbiology laboratories. The Vitek 2 automated identification system (bioMérieux) recently included C. auris in its database (version 8.01). We evaluated the performance of the Vitek 2 YST ID card to identify C. auris and related species. A panel of 44 isolates of Candida species (C. auris, n = 35; Candida haemulonii, n = 5; Candida duobushaemulonii, n = 4) were tested by three different hospital-based microbiology laboratories. Among 35 isolates of C. auris, Vitek 2 yielded correct identification in an average of 52% of tested samples. Low-discrimination (LD) results with an inability to distinguish between C. auris, C. duobushaemulonii, and Candida famata were obtained in an average of 27% of samples. Incorrect identification results were obtained in an average of 21% of samples, the majority (91%) of which were reported as C. duobushaemulonii and the remaining 9% of which were reported as Candida lusitaniae/C. duobushaemulonii. The proportion of correct identification was not statistically different across different centers (P = 0.78). Stratification by genetic clades demonstrated that 100% (n = 8) of the strains of the South American clade were correctly identified compared to 7% (n = 10) and 0% (n = 4) from the African and East Asian clades, respectively. None of the non-auris Candida strains (n = 9) were incorrectly identified as C. auris Our results show that the Vitek 2 (version 8.01) yeast identification system has a limited ability to correctly identify C. auris These data suggest that an identification result for C. duobushaemulonii should warrant further testing to rule out C. auris The overall performance of the Vitek 2 seems to differ according to C. auris genetic clade, with the South American isolates yielding the most accurate results.

Evaluation of the Abbott ARCHITECT™ cytomegalovirus IgM/IgG, rubella IgM/IgG, and syphilis treponemal antibodies enzyme immunoassays in a mother and child health center population.

This study evaluated the concordance of Architect™ chemiluminescent microparticle immunoassays with Captia™ ELISA for cytomegalovirus (CMV) IgM and IgG, with Enzygnost™ and Captia™ ELISA for rubella IgM and IgG and with Trep-Sure™ ELISA for syphilis treponemal antibodies in a mixed pediatric and obstetrical population. Total agreement between assays and Kappa statistic value were 82.5% (95% CI: 75.6-87.7) and 0.65 (95% CI: 0.54-0.77) for CMV IgM, 82.8% (95% CI: 76.7-87.6) and 0.65 (95% CI: 0.55-0.75) for CMV IgG, 89.2% (95% CI: 82.9-93.4) and 0.56 (95% CI: 0.36-0.75) for rubella IgM, 88.6% (95% CI: 82.9-92.6) and 0.74 (95% CI: 0.63-0.84) for rubella IgG, and 97.9% (95% CI: 94.5-99.4) and 0.89 (95% CI: 0.79-1.00) for syphilis treponemal antibodies. This study demonstrates that the Architect™ chemiluminescent microparticle immunoassays correlate well with other FDA-approved ELISA assays in this specific population.

Ventilator-Associated Pneumonia and Events in Pediatric Intensive Care: A Single Center Study.

OBJECTIVES: Ventilator-associated pneumonia is the second most common nosocomial infection in pediatric intensive care. The Centers for Disease Control and Prevention recently issued diagnosis criteria for pediatric ventilator-associated pneumonia and for ventilator-associated events in adults. The objectives of this pediatric study were to determine the prevalence of ventilator-associated pneumonia using these new Centers for Disease Control and Prevention criteria, to describe the risk factors and management of ventilator-associated pneumonia, and to assess a simpler method to detect ventilator-associated pneumonia with ventilator-associated event in critically ill children. DESIGN: Retrospective, observational, single-center. SETTING: PICU in a tertiary-care university hospital. PATIENTS: Consecutive critically ill children mechanically ventilated for greater than or equal to 48 hours between November 2013 and November 2015. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 304 patients mechanically ventilated for greater than or equal to 48 hours, 284 were included. Among them, 30 (10.6%) met clinical and radiologic Centers for Disease Control and Prevention criteria for ventilator-associated pneumonia, yielding an prevalence of 7/1,000 mechanical ventilation days. Median time from mechanical ventilation onset to ventilator-associated pneumonia diagnosis was 4 days. Semiquantitative culture of tracheal aspirates was the most common microbiological technique. Gram-negative bacteria were found in 60% of patients, with a predominance of Haemophilus influenzae and Pseudomonas aeruginosa. Antibiotic therapy complied with adult guidelines. Compared with patients without ventilator-associated pneumonia, those with ventilator-associated pneumonia had significantly longer median durations of mechanical ventilation (15 vs 6 d; p < 0.001) and PICU stay (19 vs 9 d; p < 0.001). By univariate analysis, risk factors for ventilator-associated pneumonia were younger age, reintubation, acute respiratory distress syndrome, and continuous enteral feeding. Among the 30 patients with ventilator-associated pneumonia, 17 met adult ventilator-associated event's criteria (sensitivity, 56%). CONCLUSIONS: Ventilator-associated pneumonia is associated with longer times on mechanical ventilation and in the PICU. Using the ventilator-associated event criteria is of interest to rapidly screen for ventilator-associated pneumonia in children. However, sensitivity must be improved by adapting these criteria to children.

MRSA eradication of newly acquired lower respiratory tract infection in cystic fibrosis.

UK cystic fibrosis (CF) guidelines recommend eradication of methicillin-resistant Staphylococcus aureus (MRSA) when cultured from respiratory samples. As there is no clear consensus as to which eradication regimen is most effective, we determined the efficacy of eradication regimens used in our CF centre and long-term clinical outcome. All new MRSA positive sputum cultures (n=37) that occurred between 2000 and 2014 were reviewed. Eradication regimen characteristics and clinical, microbiological and long-term outcome data were collected. Rifampicin plus fusidic acid was the most frequently used regimen (24 (65%) out of 37 patients), with an overall success rate of 79% (19 out of 24 patients). Eradication failure was more likely in patients with an additional MRSA-positive peripheral screening swab (p=0.03) and was associated with worse survival (p=0.04). Our results demonstrate the feasibility and clinical benefits of MRSA eradication. As peripheral colonisation was associated with lower eradication success, strategies combining systemic and topical treatments should be considered to optimise outcomes in CF patients.

Evaluation of the abbot Architect(™) epstein-barr virus viral capsid antigen IgM, viral capsid antigen IgG and nuclear antigen IgG assays in a pediatric and adult population.

BACKGROUND: The detection of antibodies against Epstein-Barr viral capsid (VCA) and nuclear (EBNA) antigens is routinely performed with different commercially available immunoassays. OBJECTIVES: In this study, we evaluated the concordance and performance of the Architect(™) chemiluminescent microparticle immunoassays (CMIAs) using Captia(™) enzyme linked immunosorbent assays (ELISA) for VCA IgM, and standard immunofluorescence (IF) assays for VCA IgG and EBNA IgG as comparative techniques. STUDY DESIGN: Sera were selected from a heterogeneous population including pediatric and adult patients. RESULTS: Concordance between CMIAs and comparative assays was high with total agreement percentages of 84,1% (95% CI: 77.8-88.9) for VCA IgM, 90,6% (95% CI: 84.2-94.7) for EBNA IgG and 98,0% (95% CI: 93.9-99.6) for VCA IgG. Moreover, kappa statistic values showed good to excellent correlation with values of 0.68 (95% CI: 0.57-0.79) for VCA IgM, 0.73 (95% CI: 0.58-0.87) for EBNA IgG and 0.95 (95% CI: 0.89-1.00) for VCA IgG. A correlation was observed between positivity levels on CMIAs and semi-quantitative fluorescence intensity on IF for VCA IgG and EBNA IgG assays. With regard to an accepted gold standard IF assays, CMIA was 98,1% (95% CI: 93.3-99.8) sensitive and 97,4% (95% CI: 86.5-99.9) specific for the detection of VCA IgG. For the detection of EBNA IgG, it was 92,2% (95% CI: 85.1-96.6) sensitive and 84,6% (95% CI: 65.1-95.6) specific. CONCLUSION: In summary, we demonstrated that the CMIA EBV antibody detection panel has high performance and high concordance with other commercially available immunoassays.

Evaluation of a fluorescent immunoassay rapid test (Sofia™) for detection of influenza A+B and RSV in a tertiary pediatric setting.

In response to the lack of sensitivity and reproducibility of previously marketed rapid antigen detection tests, a novel fluorescent immunoassay was recently developed. This new assay offers rapidity and automated reading. More characterization of this assay is needed. The aim of this study was to assess diagnostic performance of Sofia influenza A+B and respiratory syncytial virus (RSV) while compared to traditional viral cell culture. A total of 416 respiratory samples were analyzed prospectively with both methods in a tertiary pediatric center. Sensitivity and specificity of the Sofia™ test were 90.0% and 98.0% for influenza A, 90.9% and 98.9% for influenza B, and 87.7% and 94.7% for RSV compared to traditional cell culture. Overall, Sofia influenza A+B and RSV assays performed well in comparison to culture in a pediatric population.

Clinical and economical impact of multiplex respiratory virus assays.

During the last decade, a variety of molecular assays targeting respiratory viruses have been developed and commercialized. Therefore, multiplex PCR are increasingly used in everyday clinical practice. This improves our understanding of respiratory virus epidemiology and enhances our concerns about their clinical impact in specific patient populations. However, questions remain regarding cost-effectiveness of performing these diagnostic tests in routine and their real impact on patient care. This article will review available data and highlight unresolved questions about cost-effectiveness, infection control, clinical utility and public health impact of multiplex respiratory virus assays.

Comparison of three different methods for detection of Shiga toxin-producing Escherichia coli in a tertiary pediatric care center.

Shiga toxin-producing Escherichia coli (STEC) is a well-known cause of sporadic and epidemic food-borne gastroenteritis. A low infectious dose, approximately 10 microorganisms, is sufficient to cause disease that may lead to hemolytic-uremic syndrome. The objective of this study was to compare the performances of an in-house real-time PCR, a commercial enzyme immunoassay (EIA) (Premier EHEC; Meridian Bioscience), and culture on sorbitol MacConkey agar for the detection of STEC in a tertiary care pediatric hospital. Of 632 stool samples tested, 21 were positive for STEC. All were detected by PCR, 6 were detected by EIA, and only 5 O157 STEC isolates were identified by culture. Among the 15 specimens falsely negative by EIA, there were 9 Stx1, 2 Stx2, and 4 Stx1 and Stx2 STEC isolates. The latter group included 2 O157 STEC isolates that would have been missed if only EIA had been performed. To our knowledge, this is the first prospective study performed in a pediatric hospital which demonstrates the superiority of PCR over EIA for the detection of STEC. We conclude that PCR is specific and more sensitive than EIA. PCR should be considered for routine use in clinical settings where molecular detection facilities are available. Its lower limit of detection, equivalent to the infectious dose, is an obvious advantage for patient care and public health surveillance.