Evaluation of a novel, rapid antigen detection test for the diagnosis of SARS-CoV-2

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) is currently finally determined in laboratory settings by real-time reverse-transcription polymerase-chain-reaction (rt-PCR). However, simple testing with immediately available results are crucial to gain control over COVID-19. The aim was to evaluate such a point-of-care antigen rapid test (AG-rt) device in its performance compared to laboratory-based rt-PCR testing in COVID-19 suspected, symptomatic patients.

Methods

For this prospective study, two specimens each of 541 symptomatic female (54.7%) and male (45.3%) patients aged between 18 and 95 years tested at five emergency departments (ED, n = 296) and four primary healthcare centres (PHC, n = 245), were compared, using AG-rt (positive/negative/invalid) and rt-PCR (positive/negative and cycle threshold, Ct) to diagnose SARS-CoV-2. Diagnostic accuracy, sensitivity, specificity, positive predictive values (PPV), negative predictive value (NPV), and likelihood ratios (LR+/-) of the AG-rt were assessed.

Results

Differences between ED and PHC were detected regarding gender, age, symptoms, disease prevalence, and diagnostic performance. Overall, 174 (32.2%) were tested positive on AG-rt and 213 (39.4%) on rt-PCR. AG correctly classified 91.7% of all rt-PCR positive cases with a sensitivity of 80.3%, specificity of 99.1%, PPV of 98.3, NPV of 88.6%, LR(+) of 87.8, and LR(-) of 0.20. The highest sensitivities and specificities of AG-rt were detected in PHC (sensitivity: 84.4%, specificity: 100.0%), when using Ct of 30 as cut-off (sensitivity: 92.5%, specificity: 97.8%), and when symptom onset was within the first three days (sensitivity: 82.9%, specificity: 99.6%).

Conclusions

The highest sensitivity was detected with a high viral load. Our findings suggest that AG-rt are comparable to rt-PCR to diagnose SARS-CoV-2 in COVID-19 suspected symptomatic patients presenting both at emergency departments and primary health care centres.

Splicing factors differentially expressed in psoriasis alter mRNA maturation of disease-associated EDA+ fibronectin

The EDA+ fibronectin splicing variant is overexpressed in psoriatic non-lesional epidermis and sensitizes keratinocytes to mitogenic signals. However, regulation of its abundance is only partially understood. In our recent cDNA microarray experiment, we identified three SR-rich splicing factors-splicing factor, arginine/serine-rich 18 (SFRS18), peptidyl-prolyl cis-trans isomerase G (PPIG), and luc-7 like protein 3 (LUC7L3)-which might be implicated in the preactivated states of keratinocytes in psoriatic non-involved skin and could also contribute to the regulation of fibronectin mRNA maturation. In this study, we investigated the role of LUC7L3, PPIG, and SFRS18 in psoriasis and in the mRNA maturation process of fibronectin. Regarding tissue staining experiments, we were able to demonstrate a characteristic distribution of the splicing factors in healthy, psoriatic non-involved and involved epidermis. Moreover, the expression profiles of these SR-rich proteins were found to be very similar in synchronized keratinocytes. Contribution of splicing facwwtors to the EDA+ fibronectin formation was also confirmed: their siRNA silencing leads to altered fibronectin mRNA and protein expression patterns, suggesting the participation in the EDA domain inclusion. Our results indicate that LUC7L3, PPIG, and SFRS18 are not only implicated in EDA+ fibronectin formation, but also that they could possess multiple roles in psoriasis-associated molecular abnormalities.

Imported dengue fever in Austria 1990–2005

Dengue is the most important human viral disease transmitted by an arthropod vector. The steadily increasing numbers of tourists visiting endemic areas coupled with the present resurgence of dengue, raises the risk of exposure for large numbers of travelers and imported dengue cases are increasingly observed in non-endemic countries. We aimed to study the epidemiology, clinical manifestations and laboratory findings in imported dengue at a City of Vienna hospital. Medical records of 93 patients (age: 17-68 years, 43f, 50m) with imported dengue in Vienna between 1990 and April 2005 were analyzed retrospectively. Forty-eight (52%) were classified as confirmed and 45 (48%) as probable dengue, according to the CDC criteria. The patients acquired the infection in South East Asia (56%), the Indian subcontinent (18%), Africa (10%) and Oceania (3%). The most important symptoms were fever, headache, arthralgia and myalgia, nausea and vomiting, diarrhea, chills, extreme fatigue and dizziness. A rash was observed in 43%, and lymphadenopathy in 22%. Laboratory findings were thrombocytopenia, leukopenia and elevated hepatic enzymes. Eighteen patients showed hemorrhagic manifestations, and 7 fulfilled the criteria of dengue hemorrhagic fever; 1 of them had dengue shock syndrome. Case fatality rate was nil. Dengue has to be considered in all febrile travelers returning from endemic areas. Prompt diagnosis and symptomatic treatment is warranted and should prevent patients from unnecessary and potentially harmful diagnostic and therapeutic procedures.

A holistic approach to MRSA eradication in critically ill patients with MRSA pneumonia

BACKGROUND

The number of Methicillin-resistant Staphylococcus aureus (MRSA) pneumonia cases is increasing in many European countries. In this observational study in one medical and three surgical ICUs multiple interventions for the treatment and eradication of nosocomial MRSA-pneumonia were used.

PATIENTS AND METHODS

Twenty-one critically ill patients (age: 59 +/- 14 years, 15 males/6 females, 18 ventilator-associated, 3 nosocomial, clinical pulmonary infection score > 6 in all patients, APACHE II 18 +/- 5) were enrolled. The patients were treated with a 7-day course of iv linezolid (600 mg bid) plus rifampicin (600 mg bid), endotracheal vancomycin 100 mg qid, thrice daily mouth and throat washing with chlorhexidine 1% fluid and nasal mupirocin ointment, twice daily skin and hair washings with chlorhexidine gluconate 4% and tracheostomy (n = 8) wound care with povidone-iodine spray. Control samples (endotracheal secretions, nose, wound, and pharyngeal swabs) were taken 2, 3, 4, 7 days and 2 months thereafter. Multilobular pneumonia was seen in 16, pleural effusion in 12, and MRSA bacteremia in 4 patients.

RESULTS

One patient died during the follow-up period due to cerebral bleeding. In the remaining 20 patients, pneumonia was clinically cured in all patients and all patients were free of MRSA after eradication. Six patients died due to myocardial infarction (n = 3), gram-negative septic shock (n = 2), herpes encephalitis (n = 1) > 7 days after eradication. No MRSA reinfection occurred during the control period.

CONCLUSION

We conclude that in patients with MRSA pneumonia an approach using a 7-day course of intravenous linezolid plus rifampicin, intratracheal vancomycin, nasal mupirocin, cutaneous and oropharyngeal chlorhexidin plus povidone-iodine cures pneumonia and is effective for MRSA eradication.

The expression of light-regulated genes in the high-pigment-1 mutant of tomato

Three light-regulated genes, chlorophyll a/b-binding protein (CAB), ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit, and chalcone synthase (CHS), are demonstrated to be up-regulated in the high-pigment-1 (hp-1) mutant of tomato (Lycopersicon esculentum Mill. ) compared with wild type (WT). However, the pattern of up-regulation of the three genes depends on the light conditions, stage of development, and tissue studied. Compared with WT, the hp-1 mutant showed higher CAB gene expression in the dark after a single red-light pulse and in the pericarp of immature fruits. However, in vegetative tissues of light-grown seedlings and adult plants, CAB mRNA accumulation did not differ between WT and the hp-1 mutant. The ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit mRNA accumulated to a higher level in the hp-1 mutant than WT under all light conditions and tissues studied, whereas CHS gene expression was up-regulated in de-etiolated vegetative hp-1-mutant tissues only. The CAB and CHS genes were shown to be phytochrome regulated and both phytochrome A and B1 play a role in CAB gene expression. These observations support the hypothesis that the HP-1 protein plays a general repressive role in phytochrome signal transduction.

Cholera toxin elevates pathogen resistance and induces pathogenesis-related gene expression in tobacco

In animals, plants and fungi, cholera toxin (CTX) can activate signalling pathways dependent on heterotrimeric GTP binding proteins (G-proteins). We transformed tobacco plants with a chimeric gene encoding the A1 subunit of CTX regulated by a light-inducible wheat Cab-1 promoter. Tissues of transgenic plants expressing CTX showed greatly reduced susceptibility to the bacterial pathogen Pseudomonas tabaci, accumulated high levels of salicylic acid (SA) and constitutively expressed pathogenesis-related (PR) protein genes encoding PR-1 and the class II isoforms of PR-2 and PR-3. In contrast, the class I isoforms of PR-2 and PR-3 known to be induced in tobacco by stress, by ethylene treatment and as part of the hypersensitive response to infection, were not induced and displayed normal regulation. In good agreement with these results, microinjection experiments demonstrated that CTX or GTP-gamma-S induced the expression of a PR1-GUS reporter gene but not that of a GLB-GUS reporter gene containing the promoter region of a gene encoding the class I isoform of PR-2. Microinjection and grafting experiments strongly suggest that CTX-sensitive G-proteins are important in inducing the expression of a subset of PR genes and that these G-proteins act locally rather than systemically upstream of SA induction.