[Etiology of severe community - acquired pneumonia in adults: results of the first Russian multicenter study].

AIM: to study the etiology of severe community - acquired pneumonia (SCAP) in adults in Russian Federation. SCAP is distinguished by high mortality and socio - economic burden. Both etiology and antimicrobial resistance are essential for appropriate antibiotic choice. MATERIALS AND METHODS: A prospective cohort study recruited adults with confirmed diagnosis of SCAP admitted to multi - word hospitals of six Russian cities in 2014-2018. Etiology was confirmed by routine culture of blood, respiratory (sputum, endotracheal aspirate or bronchoalveolar lavage) and when appropriate, autopsy samples, urinary antigen tests (L. pneumophila serogroup 1, S. pneumoniae); real - time PCR for identification of "atypical" bacterial pathogens (M. pneumoniae, C. pneumoniae, L. pneumophila) and respiratory viruses (influenza viruses A and B, parainfluenza, human metapneumovirus, etc.) was applied. RESULTS: Altogether 109 patients (60.6% male; mean age 50.8±18.0 years old) with SCAP were enrolled. Etiological agent was identified in 65.1% of patients, S. pneumoniae, rhinovirus, S. aureus and K. pneumoniae were the most commonly isolated pathogens (found in 43.7, 15.5, 14.1 and 11.3% of patients with positive results of microbiological investigations, respectively). Bacteriemia was seen in 14.6% of patients and most commonly associated with S. pneumoniae. Co - infection with 2 or more causative agents was revealed in 36.6% of cases. Combination of bacterial pathogens (mainly S. pneumoniae with S. aureus or/and Enterobacterales) prevailed - 57.7% of cases; associations of bacteria and viruses were identified in 38.5% of patients, different viruses - in one case. CONCLUSION: S. pneumoniae was the most common pathogen in adults with SCAP. A high rate of respiratory viruses (mainly rhinovirus and influenza viruses) identification both as mixt infection with bacteria and mono - infection should be taken into account.

[Mutual influence of gastrointestinal pathology and hospital-acquired infection].

Review of the literature devoted to one of the most important problems of modern medicine--nosocomial infections (NI). In the article there are examined relevant, epidemiology, pathogenesis, and criteria for NO determining. Special attention is paid to the mutual influence of gastrointestinal tract pathology and nosocomial infections.

Scattering of a Laser Beam on an Ensemble of Asymmetrical Erythrocytes.

The study describes an analytical model of laser beam scattering on an inhomogeneous ensemble of erythrocytes. The model takes into account erythrocyte variation in size, shape, and spatial orientation. A relationship is established between an experimentally determined parameter: visibility of the diffraction pattern, and a characteristic serving as a measure of inhomogeneity of erythrocyte size and shape in a blood specimen. This relationship is shown to be monotonous, which means that erythrocyte variation in size and shape can be assessed based on measurements of the diffraction pattern visibility.