The duration of SARS-CoV-2 shedding in patients recovering from COVID-19.

The knowledge of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) shedding is highly relevant to the diagnosis, treatment and follow-up of patients with COVID-19 (coronavirus disease 2019). Deep nasopharyngeal swabs repeatedly collected from a cohort of one hundred patients with COVID-19 were tested for SARS-CoV-2 RNA using RT-PCR (real-time polymerase chain reaction). The median period of viral genome detectability was 15 days. Furthermore, the authors tested the hypothesis on the relationship between the severity of COVID-19 and the period in which the viral genome is detectable. They did not find any statistically significant difference in the duration of viral clearance between patients with asymptomatic to mild disease or severe disease.

Severe community-acquired pneumonia in intensive care.

AIM: To describe the characteristics of patients with severe pneumonia treated in Czech intensive care units (ICU) and to compare this study group with the available European and world literature data. MATERIAL AND METHODS: The prospective observational study launched on 1 September 2017 includes adult patients with community-acquired pneumonia from three Czech ICUs. It focuses on demographic data, chronic comorbidity, clinical and laboratory parameters, X-ray findings, microbiological findings, therapeutic procedures, and treatment outcomes.  Results: As of 31 May 2019, 74 patients, 21 females and 53 males, were included in the study. Fifty-three (71.6%) patients had an underlying chronic disease. Only one patient was vaccinated against influenza and pneumococcal infections. The main symptoms were cough and dyspnea, in 63 (85.1%) patients, pathology on auscultation, in 64 (86.5%) patients, and fever, in 23 (31.1%) patients. Bilateral pathology on X-ray was observed in 34 (45.9%) patients. The most commonly detected pathogens were Streptococcus pneumoniae, in 22 (29.7%) patients, and influenza virus, in 16 (21.6%) patients. The etiology was not established in 23 (31.1%) patients. Third-generation cephalosporins and potentiated aminopenicillin as the most common initial empirical therapies were used in 39 (52.7%) and 20 (27%) patients, respectively. The initial therapy turned out to be effective in 59 (79.7%) patients. Forty-six (62.2%) patients required mechanical ventilation, 40 (54.1%) patients required vasopressors, and 10 (13.5%) patients required the use of renal replacement therapy. The average length of ICU stay was 15.5 days. Forty-seven (63.5%) patients were discharged home, 17 (23%) patients were transferred to long-term care facilities, and 10 (13.5%) patients died. CONCLUSIONS: The study presents the first results characterizing patients with severe community-acquired pneumonia in the Czech Republic. For most indicators, the characteristics of the Czech patients are comparable with the data from other countries, but differences were found in the pneumococcal and influenza vaccine coverage rates, which were low in the Czech Republic. Despite the appropriate empirical antibiotic therapies, severe pneumonia was associated with high mortality and prolonged morbidity.

Streptococcal toxic shock syndrome - a life-threatening condition caused by various streptococcal species.

Streptococcal toxic shock syndrome (STSS) is an acute, life-threatening condition which presents as a rapid onset shock and multiorgan failure (multiorgan dysfunction syndrome, MODS). This communication summarizes the existing body of evidence and presents three case reports. In two patients, STSS was caused by the bacterium Streptococcus pyogenes and in one patient, Streptococcus dysgalactiae was identified as the causative agent. STSS cases caused by other streptococcal species have been reported less often in the literature. A number of articles and manuals (including the CDC definition from 2010) even continue to state that STSS can only be caused by group A streptococci (S. pyogenes) [1]. To our knowledge, the case report presented of STSS caused by another streptococcal species is the first report in the Czech literature.

[Aristoteles redivivus or small repetitorium of Aristotelian methodology regarding problems of psychosomatic medicine]. / Aristoteles redivivus aneb malé repetitorium aristotelské metodologie s ohledem na problematiku psychosomatické medicíny.

Present-day biological medicine has not reconciled the modern heritage of mechanistic conception of causality, which in many aspects limits the diagnostic and therapeutic potential of contemporary physicians. If such reduced principle of causality is confronted with Aristotelian conception of four types of disease causes and with the possibility to use it in the study of life nature (and therefore also in medicine), non-trivial differences will be revealed, which can at least bring some inspiration to present day physicians. The contemporary psychosomatically thinking physicians are in a similar position from which Aristotle criticized his foregoers for insufficient explanation of the principle of cause and effect. Medical doctors have many common points with Aristotle and that is why it is possible to speak, with certain hyperbole, about renewal of Aristotelian conceptions in some of the new trends of contemporary medicine, where the present-day mechanistic mentality is replaced with ecosystematic thinking.

Experimental confirmation of a hepatitis B virus (HBV) epsilon-like bulge-and-loop structure in avian HBV RNA encapsidation signals.

Hepatitis B viruses replicate via reverse transcription of an RNA intermediate. This RNA pregenome serves as mRNA and is packaged into capsids and reverse transcribed. Both processes require the interaction of the viral reverse transcriptase, P protein, with the 5'-proximal epsilon-signals on the pregenome. For epsilon of human hepatitis B virus (HBV), the presence of a functionally important stem-loop structure with a central bulge, part of which acts as template for a short primer of first-strand DNA synthesis, has been experimentally confirmed. Based on phylogeny and its functional similarities to epsilon, the D epsilon-signal of duck hepatitis B virus (DHBV) had been proposed to have a similar structure which does not, however, correspond to the most stable computer prediction. We have therefore experimentally determined the secondary structures of D epsilon and of the H epsilon-signal of heron hepatitis B virus which differs considerably from D epsilon in primary sequence yet interacts productively with DHBV P protein. Our data support an HBV epsilon-like structure for both D epsilon and H epsilon; in particular the bulge is highly conserved, in accord with its special function in replication. However, the apical loop in H epsilon is much enlarged suggesting that, by an induced-fit mechanism, both RNAs may adopt a new, probably similar conformation in the complex with P protein.

Hepadnavirus P protein utilizes a tyrosine residue in the TP domain to prime reverse transcription.

Hepadnavirus DNA minus strands are covalently linked at their 5' terminus to the viral P gene product, which has been taken to indicate that the hepadnaviral polymerase polypeptide itself also functions as a protein primer for initiating reverse transcription of the RNA pregenome. The present study confirms this indication by identifying the nucleotide-linked amino acid in the P protein sequence of the duck hepatitis B virus (DHBV). In a first set of experiments, mutational analysis of three phylogenetically conserved tyrosine residues in the DNA terminal (TP) domain indicated that of these, only tyrosine 96 was essential for both viral DNA synthesis in transfected cells and priming of DNA synthesis in a cell-free system. This assignment was confirmed by direct biochemical analysis: tryptic peptides from the DHBV P protein, 32P labelled at the priming amino acid by the initiating dGTP and additionally labelled internally by [35S]methionine, were isolated and analyzed in parallel to reference peptides synthesized chemically and 33P labelled by a tyrosine kinase. Mobility in high-performance liquid chromatography, as well as the release in stepwise amino acid sequencing of phospholabel and of [35S]methionine, identified the priming amino acid unequivocally as the tyrosine in the sequence 91KLSGLYQMK99, which is located in the center of the TP domain. Conserved sequence motifs surrounding Tyr-96 allow the prediction of the priming tyrosine in other hepadnaviruses. Weak sequence similarity to picornavirus genome-linked polypeptides (VPgs) and similar gene organization suggest a common origin for the mechanisms that use protein priming to initiate synthesis of viral DNA genomes or RNA genomes from an RNA template.