[Comparative estimation of diagnostic tests for helicobacter pylori and the spectrum of gastric mucosal microflora in gastritis and ulcer disease].

We estimated specificity and sensitivity of diagnostic tests for H. pylori (HP) infection in patients with gastroduodenal problems and studied species composition of gastric mucosal microflora in gastritis and ulcer disease. The following characteristics have been determined as the most informative signs of HP infection: HP fecal antigen, plasma total antibodies (IgG, IgA, IgM) against CagA, histological (cytological) findings confirming the presence of HP antigens in biopsies, rapid urease test, the presence of bent rods morphologically resembling HP in gastric mucosa biopsies cultured in the glycol medium for sterility control. The use of these signs (at least three) in combination ensures efficacious diagnostics of HP infection for the substantiation of its traditional therapy. The study of the spectrum and occurrence of gastric mucosal microflora revealed the predominance of Streptococcus, Staphylococcus, Candida fungi, and HP in patients with gastritis and Streptococcus, HP and Candida in those with ulcer disease at a mean concentration of microbial cells 3.41 and 2.71 CF/gg respectively. Significant differences were documented only in the occurrence of HP and Candida.

[Epidemiologic diagnostic of nosocomial suppurative-septic infections of Pseudomonas etiology based on intraspecies typing of causative agent].

AIM: Scientific justification of optimization of epidemiologic diagnostic of suppurative-septic infection (SSI) caused by Pseudomonas aeruginosa based on comparability of antibiotic sensitivity and beta-lactamase production. MATERIALS AND METHODS: Intraspecies typing of 37 P. aeruginosa strains isolated during microbiological monitoring of 106 patients and 131 objects of clinical environment of surgical and obstetrician hospitals by using a complex ofphenotypic and molecular-biological methods including determination of sensitivity to antibiotics by serial dilutions method and PCR-diagnostics with determination of TEM, SHV, CTX, OXA, MBL, VIM genes was performed. RESULTS: P. aeruginosa strains combined into groups by isolation location during studies turned out to be heterogeneous by sensitivity to antibiotics and beta-lactamase production that allowed to form subgroups of strains by focality attribute. Isolates recovered from different SSI foci had significant differences in minimal inhibitory concentration (MIC) reaching 1024 times. MIC parameter within subgroups did not exceed 8 - 16 consequent dilutions. CONCLUSION: Use of a complex of phenotypic and molecular-biologic methods of causative agent typing including determination of sensitivity to antibiotics by serial dilutions method and evaluation of beta-lactamase production allowed to establish a mechanism of development of SSI epidemic process caused by P. aeruginosa, detect origins and reservoirs of infection in hospital, modes and factors of transmission and reach maximum justification of epidemiologic control and prophylaxis measures of localization of foci of nosocomial infections of pseudomonas etiology.

[Estimation of MRSA susceptibility to oxacillin, cefoxitine, vancomycin and daptomycin].

Prevalence and therapy of infections due to MRSA remain one of the most serious problems in the world. Therefore, correct laboratory identification of the MRSA phenotype based on the use of the marker antibiotic cefoxitine, as a more susceptibile one vs. oxacillin, is of great importance. There is lately being observed a tendency towards emergence of strains with lower susceptibility to the last reserve drugs protecting from MRSA, i. e. vancomycin and daptomycin. Susceptibility of MSRA to these drugs was not investigated in Russia and there are no data on the prevalence of the VISA and hVISA phenotypes. The results of our study on estimation of susceptibility of 316 MRSA isolates from several regions of Russia to oxacillin, cefoxitine, vancomycin and daptomycin are presented herein. It was shown that the ranges of the oxacillin MIC were extremely wide, i. e. 0.5 to 512 mcg/ml, while 2.2 +/- 1% of the isolates was susceptible by the phenotype to oxacillin, in spite of the mecA gene presence. As for cefoxitine, the MRSA isolates were rather resistant to it at the MIC > 16 mcg/ml. The tests with serial microdilutions revealed that 30.7 +/- 7% of the isolates had a critical level of susceptibility to vancomycin at the MIC 2 mcg/ml. The E-tests revealed 1.3 +/- 1% of the isolates which were susceptible at the MIC 2-4 mcg/ml. The MRSA isolates were highly susceptible to daptomycin, while high levels of the MIC (2 mcg/ml) were characteristic of 2.8 +/- 1% of the isolates. Cross reduction of the susceptibility to vancomycin and daptomycin was observed.

[Staining of microsporidian spores with diamidine phenylindole].

A number of microscopic techniques and dyes are available to diagnose microsporidian infections in invertebrate and vertebrate hosts. Among these, DNA-specific fluorochrome DAPI is widely used to stain DNA in prokaryotic and eukaryotic cells, alone or in combination with other histochemical or fluorescent dyes. Moreover, this dye also binds to membraneous structures and protein complexes. In our studies, DAPI was used to stain spores of microsporidia infecting orthopteran, coleopteran, dipteran and lepidopteran insect hosts. DAPI staining of diplokarya helped to discriminate the Nosema-like microsporidian spores from spore-shaped bodies lacking this characteristic staining. It was found, moreover, that non-DNA staining occurred in many cases and other components of the spores were stained: the exospore, the cytoplasm, the extruded polar filament and the polaroplast. Staining of these structures was feeble as compared to DNA and in most cases did not interfere with nuclear apparatus staining. Feebly stained cytoplasm and exospore clearly indicated unstained zone of endospore, making it easier to diagnose both mono- and diplokaryotic spores. Staining of extruded polar filament allowed to demonstrate viability and to observe some stages of extrusion process of microsporidian spores.

[Microflora of gastric mucosa, its properties and role in the development of acute and chronic gastritis].

Gastric microflora was studied in 28 patients suffering acute and chronic gastritis with reference to the factors of pathogenicity and sensitivity to antibacterial preparations. A total of 55 bacterial species were isolated The microflora was dominated by streptoccoci while Helicobacter pylori occurred rather rarely 27.3 +/- 6.5% of the isolated strains showed urease activity 36.3 +/- 6.5% natural or acquired virulence, 45.5 +/- 6.7% resistance to eradication therapy.

[Microbiological monitoring of wound secretion and urinary tracts in patients and environment objects in suppurative surgery unit of a multiprofile surgical hospital].

Scientific grounding of microbiological monitoring of clinical materials of patients and environment objects in a multiprofile surgical hospital aimed at detection of the leading hospital pathogens including the polyresistant ones is presented. Entire microbiological screening of the wound secretion and urinary tracts in patients with purulent surgical wounds versus the results of the sanitary and bacteriological examinations of the environment objects revealed a high number of polyresistant strains because of unsatisfactory antiepidemic discipline and irrational use of empiric antibacterial therapy.

[Risk factors of development of nosocomial pyogenic and septic infections in maternity hospitals].

During prospective epidemiological surveillance cases of pyogenic and septic infections (PSI) in mothers and newborns in two maternity hospitals were studied using standard case definition and leading risk factors of their development were revealed. These factors differed in two hospitals and were connected mainly with high level of patients colonization, contamination of the environment by nosocomial strains of microorganisms, and degree of participation of mother's relatives in delivery. It was shown that permission to relatives for presence on delivery did not influence on the rate of PSI. Specificity of risk factors of PSI in mothers and newborns dictates necessity to determine them in each maternity hospital.