Isolation and identification of listeria in clinical material.

Results from research on isolation, identification, and study of biological properties of L. monocytogenes clinical isolates and Listeria spp test strains are presented. Peculiarities of modern research methods for indicating and identifying pathogenic listeria to improve the quality of laboratory studies of clinical material are studied. The culture method provides reliable results of microbiological analyses upon detecting Listeria spp. The presented list and algorithm of the laboratory diagnostic methods can be used as a basis for elaborating regulatory documents for carrying out microbiological research on any biological material for the presence of bacteria of the genus Listeria spp. and L. monocytogenes species in it.

A study of antibiotic and disinfectant susceptibility of Elizabethkingia meningoseptica.

For the local health service, Elizabethkingia meningoseptica remains a relatively new and little-known pathogen, whereas in many countries of Europe, Asia and other continents it is considered as a potential causative agent of nosocomial infections, especially in premature infants and immunocompromised patients. An analysis of the literature data, as well as our results indicate that E. meningoseptica should be considered as a potential pathogen, which is characterized by a unique profile of susceptibility to antimicrobial agents (AMP) and disinfectants. This article presents the results of a study of susceptibility to AMP and disinfectants of three isolates of E. meningoseptica, isolated during an investigation of an outbreak in one of the perinatal centers of the Russian Federation, where three cases of sepsis with a fatal outcome in premature infants caused by co-infection with Acinetobacter baumannii and E. meningoseptica were recorded between January and February 2016.

[Effect of cold plasma on the E. coli cell wall and plasma membrane].

The effect of cold plasma on E. coli cells was studied. It was shown that the treatment of E. coli cells with cold plasma caused partial or total disruption of the plasma membrane integrity, which was accompanied by a release ofintracellular substances into the extracellular environment. A quantitative assessment of the extent of the damage to the cell membrane showed that a loss of no more than 23.6% of intracellular substances (calculated by the proportion of the intracellular nucleotide release) is sufficient to lead to cell death. The use of media with different ionic strength levels to create osmotic shock showed that the treatment of E. coli cells with cold plasma significantly decreased the cell wall strength.

[Comparative assessment of dot-immunoassay and immunochromatography methods for detection of 01 serogroup of vibrio cholerae].

AIM: Comparative study of sensitivity and specificity of immunochromatographic (IC) assay kit and dot-immunoanalysis for assessment of feasibility of their use for laboratory diagnostics of cholera. MATERIALS AND METHODS: Experimental lots of IC assay kit and dot-immunoassay (DIA) for detection of Vibrio cholerae serogroup 01 serovars Ogava and Inaba were constructed on the basis of species-specific monoclonal antibodies (MCA) conjugated with colloid gold (IC) and peroxidase (DIA). Hybridoma-producer of MCAwas obtained and stored in liquid nitrogen in Rostov-on-Don Research Institute for Plague Control. It was deposited in specialized collection of cell cultures of vertebrates in Institute of Cytology (Saint Petersburg). RESULTS: Strong specificity of IC assay kit and DIA relative to cholera vibrios 01 and absence of crossreactivity with closely related and heterologous microorganisms were shown. Minimal quantity of vibrios, which could be detected using IC assay kit and DIA, was 107 and 105-106 microbial cells respectively. CONCLUSION: Performance of IC assay takes 5-15 min, DIA--1.5 hour, they allow to visually assess the reaction, do not require instrumentation and in perspective both methods could be used on defined stages of scheme for laboratory analysis of cholera.

[Genetic and immunochemical study of Legionella strains isolated in Sverdlovsk region].

Two strains of Legionella isolated from patient and hot water supply system during outbreak in Sverdlovsk region in 2007 were studied. Using genetic analysis methods (genes sequencing, VNTR-typing and PCR-based study of omp 28 gene), it was shown that tested strains are pathogenic but do not belong to one genetic group and epidemic cluster. Performed immunochemical analysis confirmed that both isolated strains belong to Legionella serogroup 1.

[Legionelbacagar: opportunities and prospects].

Studies results about characteristics of growth medium for Legionella cultivation--legionelbacagar--are presented in article. It was shown that the medium has good growth characteristics and prolonged shelf life. Successful use of this medium for cultivation of Legionella pneumophila strains isolated during outbreak in Sverdlovsk region in 2007 was demonstrated. Feasibility of its use for isolation of Legionella from environment and clinical samples was discussed.

[Disinfectants and main sanitary and preventive measures for protection of ventilation and air-conditioning systems from Legionella contamination].

The study was devoted to selection and assessment of disinfecting preparations for prevention of contamination by Legionella. Using system of criteria for quality assessment of disinfectants, seven newdomestic ones belonging to quaternary ammonium compounds class or to oxygen-containing preparations and designed for disinfecting of air-conditioning and ventilation systems were selected. Antibacterial and disinfecting activities of working solutions of disinfectants were tested in laboratory on the test-surfaces and test-objects of premises' air-conditioning and ventilation systems contaminated with Legionella. High antimicrobial and disinfecting activity of new preparations "Dezactiv-M", "ExtraDez", "Emital-Garant", "Aquasept Plus", "Samarovka", "Freesept", and "Ecobreeze Oxy" during their exposure on objects and materials contaminated with Legionella was shown. Main sanitary and preventive measures for defending of air-conditioning and ventilation systems from contamination by Legionella species were presented.

[Development and use of a new growth medium for detection and identification of sanitary-indicative microorganisms].

Threat of emergence and spreading of dangerous intestinal infections determines the necessity to control for water quality in its sources in respect of sanitary-indicative microorganisms, thermo-tolerant coliforms and lactose-negative intestinal bacilli testifying fecal pollution. Standard techniques for isolation of enterobacteria are based on use of lactose-containing inhibitory and non-inhibitory growth media such as lactase-peptone and Kessler media. Development of standard, effective, and reliable for use in laboratory conditions accumulation medium for detection of enterobacteria aimed to increase reliability of sanitary-bacteriological monitoring of objects of aquatic environment. Two variants of Eikman medium with an added indicator were designed for differentiation of enterobacteria on the basis of lactose and glucose fermentation with application of a thermo-tolerance test at 44-46 degrees C. Maximal accumulation of coliforms on the developed media in static cultivation conditions and at sensitivity on the level of individual cells was observed after 16 +/- 2 hours, whereas in control inhibitory media--after 22 +/- 2 hours. Studies on sterilization of the developed media in disposable packages byy-irradiation were conducted to elucidate the possibility of their use in field conditions performing analysis in flasks for preservation of high growth properties. In order to reduce time for analysis on confirmation of detection of thermotolerant coliforms, addition of tryptophan in composition of the media was provided, which allows to perform an indole test and definitively confirm the detection of Escherichia coli. Pilot industrial samples of designed media were successively passed the approbation.

[Characterization of Escherichia coli strains O157:H7, isolated on the territories of the Central Federal District].

The characterization of E.coli strains O157:H7, isolated from humans and animals on some territories of the Central Federal District, is presented. Among the isolates from human outbreaks, related and, probably, related cultures prevailed, while among the isolates obtained from different animals mainly unrelated cultures have been detected. A conclusion has been made concerning the existence of several independent zoonotic reservoirs of E. coli O157:H7 infection on this territory. The advantages and drawbacks of the use of pulse electrophoresis in the characterization of E. coli O157:H7 are discussed. Grounds are given for the necessity of the patients examination with hemorrhagic enetrocolitis for the presence of E. coli O157:H7, as well as for the expediency of having a special item for the registration of this E. coli infection in relevant statistical forms.

[Diagnostic value of a novel nutrient medium for isolation and cultivation of pathogens causing enteric yersiniosis and pseudotuberculosis]. / Diagnosticheskaia tsennost' novoi pitatel'noi sredy dlia vydeleniia i kul'tivirovaniia vozbuditelei kishechnogo iersinioza i pseudotuberkuleza.

A new nutrient medium for isolation and cultivation of the causative agents of enteric yersiniosis and pseudotuberculosis was found to have advantages over Endo medium in its differentiating and inhibiting properties. This medium permitted the easy differentiation of Yersinia pseudotuberculosis from Y. enterocolitica, as well as from Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, K. rhinoscleromatis, Hafnia, Enterobacter and Citrobacter by color; from Proteus inconstans by swarming. In addition, weakly swarming of P. vulgaris differed by their light bluish color and Pseudomonas aeruginosa, by the brilliance and size of colonies. Endo medium could be used only for differentiation of E. coli from lactose-negative Yersinia colonies, Klebsiella (by mucous growth) and, to a certain extent, all Proteus species (by swarming). The medium under test and the control medium inhibited the growth of Staphylococcus aureus. In contrast to Endo medium, the medium under test partially inhibited the growth of K. rhinoscleromatis and the swarming of P. inconstans. The new medium is now introduced into practice.

[Sensitivity of Escherichia coli O157:H7, a pathogen of hemorrhagic colitis, to antibacterial drugs]. / Chuvstvitel'nost' Escherichia coli O157:H7, vozbuditelia gemorragicheskogo kolita, k antibakterial'noym preparatam.

Antibioticograms of enterohemorrhagic strains of serogroup O157 Escherichia coli isolated in the Russian Federation and Japan were comparatively studied. Strains with multiple drug resistance were detected. The main biochemical characteristics of the isolates were investigated. Significant differences in susceptibility spectra of the isolates and in their fermentative properties were revealed.