New Diagnostic Strategy for Onychomycosis: First-Line Utilization of DermaGenius® PCR and Calcofluor Microscopy Combined with Selective Culturing.

Onychomycosis (OM) is a widespread infection requiring prolonged treatment with potential side effects. Diagnostic certainty is therefore essential before initiating antifungal therapy. Molecular biology has already shown benefits in reducing the time to diagnosis, providing technical ease, and increasing sensitivity for the respective species that molecular tests can detect. Nevertheless, causative agents are numerous, and culture remains essential, particularly for detecting non-dermatophytes mold infections. This study compared the performance of three different diagnostic strategies: conventional culture technique, the multiplex DermaGenius® 2.0 PCR (DG), and a mixed PCR/culture algorithm guided by the result of direct examination with calcofluor (DEC). The mixed algorithm (MA) prioritizes DG PCR and DEC as the primary diagnostic tools, supplemented by selective sample inoculation when mycelial elements are visualized in DEC and when DG PCR fails to detect any fungus or identifies a fungus with morphology differing from that observed in DEC (filamentous fungi versus yeasts). With only 13% of samples requiring inoculation, MA emerged as the most effective strategy, demonstrating significantly higher sensitivity (98.18%; p < 0.001) compared to single-method approaches (78.18% for DG PCR alone and 74.55% for culture alone) while maintaining a specificity comparable to DG PCR (100%). This new approach saves time in result delivery, requires fewer human resources, and increases diagnostic accuracy to better meet the needs of clinicians.

Estimation of antimicrobial resistance of Mycoplasma genitalium, Belgium, 2022.

BackgroundAntimicrobial resistance (AMR) of Mycoplasma genitalium (MG) is a growing concern worldwide and surveillance is needed. In Belgium, samples are sent to the National Reference Centre of Sexually Transmitted Infections (NRC-STI) on a voluntary basis and representative or robust national AMR data are lacking.AimWe aimed to estimate the occurrence of resistant MG in Belgium.MethodsBetween July and November 2022, frozen remnants of MG-positive samples from 21 Belgian laboratories were analysed at the NRC-STI. Macrolide and fluoroquinolone resistance-associated mutations (RAMs) were assessed using Sanger sequencing of the 23SrRNA and parC gene. Differences in resistance patterns were correlated with surveillance methodology, socio-demographic and behavioural variables via Fisher's exact test and logistic regression analysis.ResultsOf the 244 MG-positive samples received, 232 could be sequenced for macrolide and fluoroquinolone RAMs. Over half of the sequenced samples (55.2%) were resistant to macrolides. All sequenced samples from men who have sex with men (MSM) (24/24) were macrolide-resistant. Fluoroquinolone RAMs were found in 25.9% of the samples and occurrence did not differ between socio-demographic and sexual behaviour characteristics.ConclusionAlthough limited in sample size, our data suggest no additional benefit of testing MG retrieved from MSM for macrolide resistance in Belgium, when making treatment decisions. The lower occurrence of macrolide resistance in other population groups, combined with emergence of fluoroquinolone RAMs support macrolide-resistance testing in these groups. Continued surveillance of resistance in MG in different population groups will be crucial to confirm our findings and to guide national testing and treatment strategies.

Relevance of cycle threshold values in mass screening by reverse-transcription-PCR during COVID-19 pandemic in Belgium: a decision-making support?

Aim: The Belgium's strategy against COVID-19 was partly based on mass screening. Here, we reported the results observed in a Belgian mass screening center. Materials & methods: Between October 2020 and February 2021, 32,089 samples were collected analyzed with reverse-transcription PCR (Thermo Fisher Scientific kits and apparatus). Patients were categorized according to their contagiousness (extrapolated from the cycle threshold [Ct] values and the recommendation of Sciensano). Results: We observed association between Ct values and age, with higher Ct observed in extreme age groups (<6 years and >75 years). Conclusion: The analysis of the evolution of the contagiousness of these patients tested twice within a 7-day period showed the relevancy of the recommendation edited by Sciensano.

Nationwide Harmonization Effort for Semi-Quantitative Reporting of SARS-CoV-2 PCR Test Results in Belgium.

From early 2020, a high demand for SARS-CoV-2 tests was driven by several testing indications, including asymptomatic cases, resulting in the massive roll-out of PCR assays to combat the pandemic. Considering the dynamic of viral shedding during the course of infection, the demand to report cycle threshold (Ct) values rapidly emerged. As Ct values can be affected by a number of factors, we considered that harmonization of semi-quantitative PCR results across laboratories would avoid potential divergent interpretations, particularly in the absence of clinical or serological information. A proposal to harmonize reporting of test results was drafted by the National Reference Centre (NRC) UZ/KU Leuven, distinguishing four categories of positivity based on RNA copies/mL. Pre-quantified control material was shipped to 124 laboratories with instructions to setup a standard curve to define thresholds per assay. For each assay, the mean Ct value and corresponding standard deviation was calculated per target gene, for the three concentrations (107, 105 and 103 copies/mL) that determine the classification. The results of 17 assays are summarized. This harmonization effort allowed to ensure that all Belgian laboratories would report positive PCR results in the same semi-quantitative manner to clinicians and to the national database which feeds contact tracing interventions.

Multicenter Evaluation of the Idylla GeneFusion in Non-Small-Cell Lung Cancer.

Targeted therapy in lung cancer requires the assessment of multiple oncogenic driver alterations, including fusion genes. This retrospective study evaluated the Idylla GeneFusion prototype, an automated and ease-of-use (<2 minutes) test, with a short turnaround time (3 hours) to detect fusions involving ALK, ROS1, RET, and NTRK1/2/3 genes and MET exon 14 skipping. This multicenter study (18 centers) included 313 tissue samples from lung cancer patients with 97 ALK, 44 ROS1, 20 RET, and 5 NTRKs fusions, 32 MET exon 14 skipping, and 115 wild-type samples, previously identified with reference methods (RNA-based next-generation sequencing/fluorescence in situ hybridization/quantitative PCR). Valid results were obtained for 306 cases (98%), overall concordance between Idylla and the reference methods was 89% (273/306); overall sensitivity and specificity were 85% (165/193) and 96% (108/113), respectively. Discordances were observed in 28 samples, where Idylla did not detect the alteration identified by the reference methods; and 5 samples where Idylla identified an alteration not detected by the reference methods. All of the ALK-, ROS1-, and RET-specific fusions and MET exon 14 skipping identified by Idylla GeneFusion were confirmed by reference method. To conclude, Idylla GeneFusion is a clinically valuable test that does not require a specific infrastructure, allowing a rapid result. The absence of alteration or the detection of expression imbalance only requires additional testing by orthogonal methods.

Covid-19: contribution of clinical characteristics and laboratory features for early detection of patients with high risk of severe evolution.

BACKGROUND: The aim of this study was to identify early clinical and laboratory predictive factors of a severe coronavirus disease 2019 (COVID-19). METHODS: A retrospective study was conducted on adult patients hospitalized for COVID-19 in our hospital. Diagnosis was based on a positive real-time reverse transcription-polymerase chain reaction (RT-PCR) on nasopharyngeal samples. The cohort was divided into two groups, i.e. a favorable evolution (FE) group and an unfavorable evolution (UFE) group, including intensive care unit (ICU) and deceased patients.Results: A total of 198 patients were enrolled in the study, with 138 FE (70%) and 60 UFE (30%). Older age, male gender, comorbidities and dyspnea at admission constituted significantly worse prognosis factors. Among laboratory features, lymphocyte and platelet counts as well as corrected glomerular filtration rate were significantly lower in UFE patients, while neutrophil to lymphocyte ratio, inflammation biomarkers, creatinine, aspartate aminotransferase, lactate dehydrogenase (LDH), glycemia and D-dimer were significantly higher. Procalcitonin and LDH appeared as the most accurate variables according to receiver operating characteristic curves. CONCLUSIONS: This Belgian study revealed clinical and laboratory features able to predict high risk of ICU requirement, or even death, at admission time. These results provide a potential tool for patient's triage in a context of pandemic.Abbreviations: COVID-19: coronavirus disease 2019; ARDS: acute respiratory distress syndrome; DIC: disseminated intravascular coagulopathy; MOF: multi-organ failure; RT-PCR: real-time reverse transcription-polymerase chain reaction; UFE: unfavorable evolution; ICU: intensive care unit; EDTA: ethylenediamine tetraacetic acid; WBC: white blood cell count; Hb: hemoglobin level; PCT: procalcitonin; Na: sodium; K: potassium; PT: total protein, CRP: c-reactive protein; Cr: creatinine; ALAT: alanine aminotransferase; ALAT: aspartate aminotransferase; TB: total bilirubin, LDH: lactate dehydrogenase, FERR: ferritin; hs-Tnt: high sensitive-troponin T; cGFR: corrected glomerular filtration rate; QR: quick ratio; DDIM: D-dimer; FIB: fibrinogen; SD: standard deviation; IQR: interquartile ranges; ROC: receiver operating characteristics; ECMO: extracorporeal membrane oxygenation; NLR: neutrophil to lymphocyte ratio; AUC: area under the curve; BMI: body mass index.

Can the 72-hour rule based on "Blast/Abn Lymph" flag on Sysmex XN-10 optimize the workflow in hematology laboratory?

Despite the continuing improvement of automated blood cell counters, confirmation by blood smear examination remains the gold standard in case of anomalies. With a constant goal of standardisation, different experts committees (e.g. the French-speaking cellular hematology group (Groupe francophone d'hématologie cellulaire, GFHC and the ISLH International society for laboratory hematology) recently published criteria for microscopic analysis of blood smears. Cornet et al. evaluated the application of those criteria and propose to suppress any review for 72 hours when a "Blast/Abn lymph" flag is triggered for a sample with no abnormal cell on the microscopic review. The aims of our study were to retrospectively evaluate whether this 72-hour rule adequately operates and whether it is possible to extend the arbitrary 72-hour timeframe to 96h and 144h. To achieve this goal, 40,688 blood samples were collected from three French-speaking hospitals. 1,548 samples presented an isolated "Blast/Abn lymph" flag. Only 221 samples presented the application of the 72-hour rule at least once for our study period. We were able to extend this rule to 144 hours for 10 samples of them. All blood smears for which the rule was applied were verified and there was no abnormal cell on smears at 72 and 144 hours. In conclusion, the 72-hour rule derived from the GFHC's criteria is secure and reduces the slide review rate and thus the production costs and the turnaround time of hemogram results. Further investigations could confirm that its extension to 144 hours is also adequate.

Pre-eclampsia: overview on the role of biomarkers in 2016.

Preeclampsia which affects approximatively 2% of pregnancies is a major cause of maternal and perinatal morbidity and mortality. Pathogenesis of pre-eclampsia is nowadays increasingly understood. It implies multiple actors and biomarkers appear to be playing a major role. New uses of those biomarkers for risk stratification and diagnosis of predisposed preeclamptic patients followed by obstetricians is an hot topic. The combined approach of biomarkers, medical history and obstetrical ultrasounds enables risk estimation in the first quarter and later on. A better understanding of this risk would enable better monitoring of obstetrical patients and reduce the occurrence of adverse complications for them and for the fetal well-being.