[Identification of Clinical Isolates of the Bacillus cereus Group and Their Characterization by Mass Spectrometry and Electron Microscopy].

Bacillus cereus is a spore-forming bacterium found in the environment mainly in soil. Bacillus spores are known to be extremely resistant not only to environmental factors, but also to various sanitation regimes. This leads to spore contamination of toxin-producing strains in hospital and food equipment and, therefore, poses a great threat to human health. Two clinical isolates identified as B. cereus and B. cytotoxicus were used in the present work. It was shown that their calcium ion content was significantly lower than that of the reference strains. According to electron microscopy, one of the SRCC 19/16 isolates has an enlarged exosporium, and the SRCC 1208 isolate has large electron-dense inclusions of an unclear nature during sporulation. We can assume that these contain a biologically active component with a cytotoxic effect and possibly play a role in pathogenesis. Comparative chemical, biochemical, physiological, and ultrastructural analysis of spores of clinical isolates and reference strains of B. cereus was performed. The results we obtained deepen our understanding of the properties of spores that contribute to the increased pathogenicity of B. cereus group species.

[The role of neutrophil CD64 index in the diagnosis of infectious complications after colorectal resection]. / Rol' indeksa CD64-neitrofilov v diagnostike infektsionnykh oslozhnenii posle rezektsii tolstoi kishki.

OBJECTIVE: To determine diagnostic value of neutrophil CD64 index (iCD64n) in the diagnosis of postoperative infectious complications after colorectal resections. MATERIAL AND METHODS: Seventy-three patients underwent colorectal surgery for the period from January to December 2018. These patients were included into a single-center study. Peripheral blood samples were taken on 3 and 6 postoperative days (POD) to check iCD64n level. We analyzed incidence of postoperative infectious complications, sensitivity (Se) and specificity (Sp) of postoperative iCD64n level on the 3rd and 6th POD. RESULTS: Postoperative infectious complications developed in 10 (13.7%) patients. Median iCD64n was significantly higher (p=0.0017 for POD 3; p=0.018 for POD 6) in patients with infectious complications (1.6 on POD 3; 1.3 on POD 6) compared to those without complications (1.1 on POD 3; 0.9 on POD 6). Area under curve (AUC) on the 3rd POD was 0.8 with the cut-off value of 1.4, Se - 70%, Sp - 93.7% (p=0.002). On the 6th POD, AUC was 0.91 with cut-off value of 1.23, Se - 80%, Sp - 93.7% (p<0.001). CONCLUSION: Neutrophil CD64 index is a valuable predictor for the diagnosis of postoperative infectious complications after colorectal resections. It is a useful tool to ensure a safe early discharge.The study is registered on the website «clinictrials.gov¼ (registration number NCT03559335).

[Effectiveness of intraperitoneal chemotherapy for t4 colon cancer]. / Effektivnost' vnutribryushnoi khimioterapii pri rake obodochnoi kishki T4.

OBJECTIVE: To determine the effect of intraperitoneal chemotherapy (IPC) with mitomycin C on expression of intraperitoneal cancer cells markers in patients with T4 colon cancer. MATERIAL AND METHODS: For the period from January 2019 to April 2020, 65 patients with T4 colon cancer were included in prospective comparative study. There were 46 patients in the main group and 19 patients in the control group. In the main group, surgical procedure was followed by IPC with mitomycin C. No IPC was performed in the control group. An effectiveness of IPC was evaluated using CD133, CD24, CD26, CD44, CD184 markers expression in peritoneal lavages. RESULTS: Significant between-group differences were observed for CD133 (p=0.0168), CD24 (p=0.0455) and CD44 (p=0.0012). There was a tendency to decrease in the level of CD184 expression in both groups in the second lavage (p=0.0605). CONCLUSION: IPC in patients with T4 colon cancer can reduce the expression and proliferative potential of free cancer cells.

[The actual condition of laboratory diagnostic of Clostridium difficile-associated diarrhea; the methods of detection of toxigenic strains (review of publications).]

The Clostridium difficile-associated infection (CDI) is one of the main causes of nosocomial diarrhea. The complicacy of laboratory diagnostic results in progression of disease bringing on extensive inflammatory alterations in the wall of large intestine and characterizing by superficial necrosis of mucous membrane with development of "pseudo-membranes" resulting in development of toxic megacolon, perforation of intestinal wall, peritonitis and sepsis. The main role in diagnosing plays indication of agent and detection of its toxins. None of laboratory tests can be applied as an independent technique of laboratory diagnostic of CDI. The multi-step diagnostic can become an appropriate strategy for quick and full detection of antibiotic-associated diarrhea.

[Antagonistic activity of lactobacilli of the colon].

AIM: Study of antagonistic activity of lactobacilli of the colon against members of its autochthonous bacterial flora and agents of some acute infectious and chronic diseases of the gastrointestinal tract. MATERIALS AND METHODS: Antagonistic activity of 19 lactobacilli cultures against 28 cultures of bacteria belonging to various groups and fungi was evaluated within the framework of specially developed two-stage cultivation technique in the conditions of a combined system. The results of the study were evaluated according to a semi-quantitative scale that allows to put one or the other value of the zone of growth delay of the studied strain culture in compliance with the one or the other (low, moderate, high) level of antagonistic activity of the lactobacillus culture. RESULTS: Lactobacilli of the colon showed selective antagonistic activity against pathogenic enterobacteriae: pronounced against Salmonella enterica Serovar Enteritidis, Shigella flexneri 2b, Yersinia spp., and trace against Salmonella enterica Serovar Typhimurium. The level of antagonistic activity of lactobacilli against a wide range of members of autochthonous bacterial flora varied in a wide range, without revealing connection neither to its belonging to species, nor to its population level, nor to the belonging to group of the antagonistic effect objects. On the other hand a connection was traced with beloriging to a certain microbiota: being quite active against members of its own microbiota, lactobacilli often showed significantly lower level of antagonistic activity against cultures with the same species name isolated from other microbiota. CONCLUSION: In light of the results obtained, level of lactobacilli population may hardly be viewed as the only criteria of their full participation in the process of stabilizing microecological welfare of the colon, that allows to make a complete representation of the level of dysbiotic disorder in the mentioned biotope. With in the framework of rational bacteriological diagnostics of the level of dysbiotic disorders in the colon, evaluation of population level of lactobacilli should be evaluated along with the degree of their antagonistic activity against other components of the same microbiota.

[The role of microflora in etiology of chronic tonsillitis].

Analysis of the results of a bacteriological study involving 218 patients with various forms of chronic tonsillitis (CT) has demonstrated that they were significantly different in terms of the seeding rate of beta-hemolytic group A Streptococci (BHAS). Specifically, these microorganisms were detected in patients with paratonsillar abscess 2.5 times as frequently as in those with uncomplicated forms of chronic tonsilitis. In other words, the former group is at risk of developing such concomitant diseases as post-streptococcal rheumocarditis, glomerulonephritis, and polyarthritis. It was shown that BHAS are capable of forming a biological film at the surface of abiogenic carriers in vitro which may be a principal cause of chronic and recurring tonsillitis.