Application of a SARS-CoV-2 Antigen Rapid Immunoassay Based on Active Microfluidic Technology in a Setting of Children and Young Adults

To carry out effective and quick identification of SARS-CoV-2 from nasopharyngeal swabs and contain outbreaks, reliable and rapid tools are needed. Herein, we compared a rapid antigen test based on active microfluidic technology to an RT-qPCR assay in pediatric and young adult patients admitted to the Pediatric Emergency Unit of a Children's Hospital. Nasopharyngeal swabs collected from patients with suspected COVID-19 disease and from those without COVID-19 related symptoms, but requiring hospitalization, were performed with both antigen test and RT-qPCR assays. We included 375 patients with a median age of 5 years in the study, with an estimated overall prevalence of 7.2%. Overall, we observed a specificity of 97.4% (95% CI: 94.9-98.7) and a sensitivity of 66.6% (95% CI: 46.0-82.7) with a positive likelihood ratio (LR+) of 25.8 (95% CI: 12.8-51.8). In the subgroup of symptomatic patients, the specificity and the sensitivity were 95.2% (95% CI: 89.4-98.0) and 80.0% (95% CI: 44.2-96.5) respectively; LR+ was 16.6 (95% CI: 7.19-38.6). In the asymptomatic subset, the performance showed a specificity of 98.7% (95% CI: 95.8-99.7), a sensitivity of 58.8% (95% CI: 33.5-80.6), and an LR+ of 43.7 (95% CI: 13.3-144.0). Compared to RT-qPCR, the new microfluidic-based antigen test showed higher specificity (>95%) in the pediatric population, thus representing a suitable point-of-care testing (POCT) in a clinical setting with low prevalence of COVID-19.

Clinical Evaluation and Comparison of Two Microfluidic Antigenic Assays for Detection of SARS-CoV-2 Virus

Given the ongoing pandemic, there is a need to identify SARS-CoV-2 and differentiate it from other respiratory viral infections in various critical settings. Since its introduction, rapid antigen testing is spreading worldwide, but diagnostic accuracy is extremely variable and often in disagreement with the manufacturer's specifications. Our study compared the clinical performances of two microfluidic rapid antigen tests towards a molecular assay, starting from positive samples. A total of 151 swabs collected at the Microbiology and Virology Laboratory of A.O. "SS Antonio e Biagio e C. Arrigo" (Alessandria, Italy) for the diagnosis of SARS-CoV-2 were simultaneously tested to evaluate accuracy, specificity, and agreement with the RT-qPCR results. Both assays showed an overall agreement of 100% for negative specimens, while positive accuracy comprised between 45.10% and 54.90%. According to the manufacturer's instructions, the greatest correlation between the antigenic and molecular assays was observed for the subset with high viral load (18/19, 94.74%), while it dramatically decreased for other subsets. Moreover, the ability to differentiate between SARS-CoV-2 and Flu provides an added value and could be addressed in an epidemic context. However, an in-house validation should be performed due to differences observed in performance declared by manufacturers and those actually obtained.

Adherence to 2015 ESC Guidelines for the Treatment of Infective Endocarditis: A Retrospective Multicentre Study (LEIOT Study)

Background: Infective endocarditis (IE) is still a severe disease with elevated morbidity and mortality. Nevertheless, the last European guidelines (GL) date back to 2015, and a recent survey described a diffuse suboptimal adherence to their recommendations. Here, we described a real-life scenario about adherence to IE treatment GL. Methods: This was a retrospective, multicentric, case–control study. All the cases of IE admitted to our wards from 2016 to 2020 were enrolled. Patients were divided into two groups, according to the non-adherence (group A, cases) or adherence (group B, controls) to 2015 ESC guidelines. Only targeted treatments were considered. Groups were compared for demographic, clinical, microbiological, and laboratory data and outcome. As a post hoc analysis, we analysed the characteristics of deviations from the guidelines and how these deviations affected mortality. Results: A total of 246 patients were enrolled, with 128 (52%) in group A and 118 (48%) in group B. Groups were homogeneous except for aetiologies: staphylococcal and blood-culture-negative IE were more frequent in group A, while streptococcal and enterococcal IE were more frequent in group B (p < 0.001). In-hospital mortality was comparable in the two groups. The most frequent causes of deviations from the guidelines were use of daptomycin, in addition to standard treatments and the missing administration of rifampin or gentamycin. Conclusions: Adherence to 2015 ESC guidelines was limited but it did not affect mortality.

Escherichia coli resistance to amoxiclavulanate therapy in pediatric urinary tract infections: a rising problem

BACKGROUND

Urinary tract infections (UTIs) are a frequent disorder of childhood, mainly caused by Escherichia coli. The aim of this study was to evaluate the antimicrobial susceptibility trend in bacterial isolates in urine cultures in pediatric environment, analyzing data from our laboratory in a 6-year period.

METHODS

A retrospective study was performed in AO SS. Antonio e Biagio e Cesare Arrigo (Pediatric Hospital) of Alessandria in Piedmont, North Ital. From 2015 to 2020, in a 6-year period, 1299 urinocultures were collected. Data collection was focused on demographic characteristics (age and sex) and laboratory findings (positive urocultures, antibiogram).

RESULTS

Positive urocultures were 577, in which Escherichia coli represented most isolates (428, 74.2%). We found a statistically significant trend toward amoxiclavulanate resistance in the E. coli positive urinoculture comparing the period 2015-2018 vs. 2019-2020.

CONCLUSIONS

Actual guidelines mostly recommend for amoxicillin-clavulanate prescription as first-line option for pediatric UTI management, this indication might be partially reconsidered. Our data underline the importance to conduct surveillance studies to determine local prevalence of antibiotic resistance to optimize therapeutic management.

Epithelioid Pleural Mesothelioma Is Characterized by Tertiary Lymphoid Structures in Long Survivors: Results from the MATCH Study

Pleural mesothelioma (PM) is an aggressive tumor with few therapeutic options. Although patients with epithelioid PM (ePM) survive longer than non-epithelioid PM (non-ePM), heterogeneity of tumor response in ePM is observed. The role of the tumor immune microenvironment (TIME) in the development and progression of PM is currently considered a promising biomarker. A few studies have used high-throughput technologies correlated with TIME evaluation and morphologic and clinical data. This study aimed to identify different morphological, immunohistochemical, and transcriptional profiles that could potentially predict the outcome. A retrospective multicenter cohort of 129 chemonaive PM patients was recruited. Tissue slides were reviewed by dedicated pathologists for histotype classification and immunophenotype of tumor-infiltrating lymphocytes (TILs) and lymphoid aggregates or tertiary lymphoid structures (TLS). ePM (n = 99) survivors were further classified into long (>36 months) or short (<12 months) survivors. RNAseq was performed on a subset of 69 samples. Distinct transcriptional profiling in long and short ePM survivors was found. An inflammatory background with a higher number of B lymphocytes and a prevalence of TLS formations were detected in long compared to short ePM survivors. These results suggest that B cell infiltration could be important in modulating disease aggressiveness, opening a pathway for novel immunotherapeutic approaches.

Abstract 1064: Antiproliferative effects of Tumor Treating Fields in human mesothelioma cell lines

Despite the increasing knowledge of the biology of malignant pleural mesothelioma (MPM), patients with this diagnosis still have a poor prognosis with a 5-year survival rate of lower than 10%. The effectiveness demonstrated by Tumor Treating Fields (TTFields) in combination with chemotherapy in preclinical experiments and in MPM patients (NCT02397928) affirms TTFields as a promising therapeutic tool. Knowledge of the mechanism of action of TTFields and its interaction with chemotherapeutic agents may contribute to the design of more effective clinical trials for MPM patients. A panel of primary MPM cells was isolated from pleural effusion and/or lavages of patients' thoracic cavity, before administration of therapeutic treatment, obtaining six cell lines from the 3 types of MPM cells: epithelioid CD473 and CD484, sarcomatoid CD60 and CD432, and biphasic CD487 and CD491. RNAseq analysis revealed that the transcriptional profiles of CD473 and CD60 cells were comparable with those derived from patient biopsies of the same histotype, representing clinically relevant MPM models. Antiproliferative effects induced by TTFields alone (1.12 V/cm; 150 KHz; for 96h duration) were studied in these MPM cell lines. Cell survival and cell cycle perturbations analyses during and after treatment were performed. Consistent with clinical observations, epithelioid MPM cells demonstrated greater sensitivity to TTFields than biphasic and sarcomatoid MPM cells. Cell cycle analysis revealed that the former cell type was blocked in G2M phase and was followed by formation of polyploid cells; while the latter cell types were only slightly affected by TTFields with a general delay in all cell cycle phases. Apoptotic cells were present in all treated samples, but while epithelioid and biphasic cell death was already observed during the first 24h of treatment, sarcomatoid cells needed to be treated for at least 24h before starting apoptotic pathways. The antiproliferative effect observed in epithelioid cells was persistent even after treatment cessation, whereas biphasic and sarcomatoid cells were able to reinitiate growth upon TTFields cessation. RNAseq experiments were performed in CD473 and CD60 cells at different times during TTFields application to explore transcriptional modifications that may explicate these varied MPM cell responses. Preliminary data suggested that TTFields induced a transcriptional response already detectable at earlier time points of treatment (8h; maximum effect at 24h). The number of differentially expressed genes was higher in CD473 relative to CD60 cells (1951 in CD473 and 336 in CD60 at 24h), involving several pathways, that need to be further investigated. These data demonstrate that TTFields induce specific effects on cell proliferation in varied subsets of mesothelioma cells and provide a mechanistic rationale for future therapies and combinations with other anticancer drugs for MPM treatment.

Citation Format: Monica Lupi, Federica Mirimao, Nicolò Panini, Greta Piazza, Lara Paracchini, Laura Mannarino, Sergio Marchini, Federica Grosso, Serena Penpa, Antonio Maconi, Giovanni L. Ceresoli, Maurizio D'Incalci. Antiproliferative effects of Tumor Treating Fields in human mesothelioma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1064.

Baseline clinical characteristics and prognostic factors in hospitalized COVID-19 patients aged ≤ 65 years: A retrospective observational study

BACKGROUND

Individual differences in susceptibility to SARS-CoV-2 infection, symptomatology and clinical manifestation of COVID-19 have thus far been observed but little is known about the prognostic factors of young patients.

METHODS

A retrospective observational study was conducted on 171 patients aged ≤ 65 years hospitalized in Alessandria's Hospital from 1st March to 30th April 2020 with laboratory confirmed COVID-19. Epidemiological data, symptoms at onset, clinical manifestations, Charlson Comorbidity Index, laboratory parameters, radiological findings and complications were considered. Patients were divided into two groups on the basis of COVID-19 severity. Multivariable logistic regression analysis was used to establish factors associated with the development of a moderate or severe disease.

FINDINGS

A total of 171 patients (89 with mild/moderate disease, 82 with severe/critical disease), of which 61% males and a mean age (± SD) of 53.6 (± 9.7) were included. The multivariable logistic model identified age (50-65 vs 18-49; OR = 3.23 CI95% 1.42-7.37), platelet count (per 100 units of increase OR = 0.61 CI95% 0.42-0.89), c-reactive protein (CPR) (per unit of increase OR = 1.12 CI95% 1.06-1.20) as risk factors for severe or critical disease. The multivariable logistic model showed a good discriminating capacity with a C-index value of 0.76.

INTERPRETATION

Patients aged ≥ 50 years with low platelet count and high CRP are more likely to develop severe or critical illness. These findings might contribute to improved clinical management.