Validation of the Colibrí Instrument for Automated Preparation of MALDI-TOF MS Targets for Yeast Identification.

Recently, Copan (Italy) introduced the Colibrí instrument for automated colony picking and preparation of matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) target plates. Our study aimed to validate this system for yeasts as such testing has not been performed yet and is a missing link needed to implement the system for routine use. Fifty-five Candida strains were selected to evaluate the accuracy of Colibrí. For each strain, a sheep blood agar plate supplemented with X and V factors (HEM) and a Sabouraud agar plate (SAB) were inoculated and incubated using the WASPlab specimen processing system (Copan). After 18 h and 36 h of incubation, the isolates were spotted in parallel using Colibrí and manually onto MALDI-TOF target plates with the addition of formic acid and identified using MALDI-TOF mass spectrometry. The reproducibility was evaluated using ATCC reference and clinical isolate-derived strains. The cumulative percentage of acceptable identification scores (IDs) after 36 h was 91% for strains cultured on HEM plates using both Colibrí and the manual method. The SAB plates showed inferior results for both Colibrí (76%) and the manual method (78%). We observed an overall agreement of 92% at 18 h for identification of the strains on the HEM plates between Colibrí and the manual method and 94% after 36 h. For the SAB plates, the agreement was 78% after 18 h and 84% after 36 h. Apart from Candida dubliniensis and Candida tropicalis, all Candida species were identified with 100% accuracy using Colibrí on HEM plates. We observed good agreement between Colibrí and the manual reference method. These results demonstrate that Colibrí is a reliable system for MALDI-TOF target preparation for yeast identification, allowing increased standardization and less hands-on time.

Validation of Rapid Antimicrobial Susceptibility Testing directly from blood cultures using WASPLab®, including Colibrí™ and Radian® in-Line Carousel.

With the increase in antimicrobial resistance, fast reporting of antimicrobial susceptibility testing (AST) results is becoming increasingly important. EUCAST developed a method for rapid AST (RAST) directly from the broth of positive blood cultures (BC). Inhibition zones are read after 4, 6, and 8 h, with specific breakpoints per time point. We evaluated the RAST method based on EUCAST disk diffusion methodology with inoculation of BC broth using WASPLab® (inclusive Colibrí™ and Radian®). Forty-nine non-duplicate strains were tested: Escherichia coli n = 17, Klebsiella pneumoniae n = 7, Pseudomonas aeruginosa n = 4, Acinetobacter baumannii n = 2, Staphylococcus aureus n = 10, Enterococcus faecalis n = 6, and Enterococcus faecium n = 3. Results were compared to direct AST and standardized AST. Good categorical agreement was obtained at all time points for all groups, except P. aeruginosa. RAST cut-offs for extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales enabled the detection of all included ESBL isolates (n = 5) at all time points, except for 1 E. coli ESBL after 4 h. RAST cut-offs for carbapenemase-producing Enterobacterales enabled the detection of only one carbapenemase after 6 h. However, all carbapenemases (n = 3) were correctly detected after 8 h. Two methicillin-resistant S. aureus were included; both were correctly categorized as cefoxitin-resistant at 6 and 8 h. At 4 h, there was insufficient growth for inhibition zone interpretation. EUCAST RAST is a fast supplementary tool for direct AST of positive BC. WASPLab® provides a significant advantage as pictures are made automatically implicating that we are not strictly bound to the time points for inhibition zone interpretation.

Severe rhabdomyolysis due to idiopathic inflammatory myopathies, a wary manifestation of a heterogenous pathology.

Idiopathic inflammatory myopathies (IIM) are historically classified by The Bohan and Peter criteria. The presentation of IIM is versatile and clinical-serological findings can aid in diagnosing the underlying form of IIM. Over the past years, the discovery and the use of myositis-specific autoantibodies (MSA) and myositis-associated autoantibodies (MAA) have led to a more heterogeneous classification by the European League Against Rheumatism and American College of Rheumatology (EULAR/ACR).This paper describes a case of dermatomyositis sine dermatitis. A 70-year -old woman presented with complaints of muscle weakness and was admitted because of severe oliguric renal failure due to rhabdomyolysis. Despite treatment with hemodialysis and initial recovery, her clinic worsened again. The disease course in combination with electromyography findings, PET-scan results, and positive myositis-specific autoantibodies, that is, anti-NXP-2 antibodies, ultimately led to the diagnosis.Today, commercial kits based on line immunoassay and dot blot have mostly replaced the labor-intensive immunoprecipitation of RNA and/or proteins for detecting MSA. Though it makes routine testing of multiple MSA easy to implement in clinical practice, more validation studies are required and clinicians should be aware of its limitations, including false-positive results. When clinical suspicion for IIM is high, a negative screening for antinuclear antibodies (ANA) result does not exclude IIM and the first test of choice remains a multi-specific immunoassay for the whole spectrum of MSA.In this paper, we want to underline that there is no shortcut in diagnosing IIM. Caution is required in interpreting different EMG, PET-scan, histological, and laboratory findings. Especially in the case of rhabdomyolysis, as this is a severe and wary manifestation of myositis.

Performance of Abbott Alinity hq hematology analyzer for automated cell counting of body fluids.

INTRODUCTION: Body fluid cell counting and differentiation provide essential information for diagnosis and monitoring of diverse pathologies. We evaluated the performance of the newly launched Abbott Alinity hq hematology analyzer for automated cell counting in body fluids and compared red blood cell (RBC) and total nucleated cell (TNC) counts with the Cell-Dyn Sapphire automated hematology analyzer. Differential counts were compared with microscopic differentiation on cytocentrifuged preparations. METHODS: Background concentration limits, limit of detection (LOD), linearity, imprecision, functional sensitivity and carryover were evaluated. For method comparison, we collected 172 body fluids (17 continuous ambulatory peritoneal dialysis fluids, 56 cerebrospinal fluids and 99 serous fluids). RESULTS: Background concentration limits were ≤1000 cells/µL for RBC counts and ≤3 cells/µL for TNC counts. The LOD was 1000 RBC/µL and 5 TNC/µL. Results from linear regression analysis revealed excellent linearity. Functional sensitivity was 3000 cells/µL for RBC counts and 50 cells/µL for TNC counts. Carryover was 0.6% and 0.1% for TNC and RBC, respectively. The Alinity hq shows good clinical performance. CONCLUSION: We demonstrated comparable performance for body fluid cell counting between the Alinity hq analyzer and the Cell-Dyn Sapphire. The Alinity hq can be very useful as a screening tool for body fluid cell counting.

Serum 25(OH)D Level on Hospital Admission Associated With COVID-19 Stage and Mortality.

OBJECTIVES: Vitamin D deficiency was previously correlated with incidence and severity of coronavirus disease 2019 (COVID-19). We investigated the association between serum 25-hydroxyvitamin D (25(OH)D) level on admission and radiologic stage and outcome of COVID-19 pneumonia. METHODS: A retrospective observational trial was done on 186 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals hospitalized from March 1, 2020, to April 7, 2020, with combined chest computed tomography (CT) and 25(OH)D measurement on admission. Multivariate regression analysis was performed to study if vitamin D deficiency (25(OH)D <20 ng/mL) correlates with survival independently of confounding comorbidities. RESULTS: Of the patients with COVID-19, 59% were vitamin D deficient on admission: 47% of females and 67% of males. In particular, male patients with COVID-19 showed progressively lower 25(OH)D with advancing radiologic stage, with deficiency rates increasing from 55% in stage 1 to 74% in stage 3. Vitamin D deficiency on admission was not confounded by age, ethnicity, chronic lung disease, coronary artery disease/hypertension, or diabetes and was associated with mortality (odds ratio [OR], 3.87; 95% confidence interval [CI], 1.30-11.55), independent of age (OR, 1.09; 95% CI, 1.03-1.14), chronic lung disease (OR, 3.61; 95% CI, 1.18-11.09), and extent of lung damage expressed by chest CT severity score (OR, 1.12; 95% CI, 1.01-1.25). CONCLUSIONS: Low 25(OH)D levels on admission are associated with COVID-19 disease stage and mortality.

Humoral Immune Response to SARS-CoV-2.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology tests are clinically useful to document prior SARS-CoV-2 infections. Data are urgently needed to select assays with optimal sensitivity at acceptable specificity for antibody detection. METHODS: A comparative evaluation was performed of 7 commercial SARS-CoV-2 serology assays on 171 sera from 135 subjects with polymerase chain reaction-confirmed SARS-CoV-2 infection (71 hospitalized patients and 64 paucisymptomatic individuals). Kinetics of IgA/IgM/IgG seroconversion to viral N and S protein epitopes were studied from 0 to 54 days after onset of symptoms. Cross-reactivity was verified on 57 prepandemic samples. RESULTS: Wantai SARS-COV-2 Ab ELISA and Orient Gene COVID-19 IgG/IgM Rapid Test showed superior overall sensitivity for detection of SARS-CoV-2 antibodies. Elecsys Anti-SARS-CoV-2 assay and EUROIMMUN Anti-SARS-CoV-2 combined IgG/IgA showed acceptable sensitivity (>95%) vs the consensus result of all assays from 10 days post onset of symptoms. Wantai SARS-COV-2 Ab ELISA, Elecsys Anti-SARS-CoV-2 assay, and Innovita 2019-nCoV Ab rapid test showed least cross-reactivity, resulting in an optimal analytical specificity greater than 98%. CONCLUSIONS: Wantai SARS-COV-2 Ab ELISA and Elecsys Anti-SARS-CoV-2 assays are suitable for sensitive and specific detection of SARS-CoV-2 antibodies from 10 days after onset of symptoms.