Assessment of Resistance in <i>Burkholderia pseudomallei</i> to Benzalkonium Chloride and Antibiotics

The aim of the study was to investigate the features of resistance formation in Burkholderia pseudomallei to quaternary ammonium compounds, as well as to analyze its influence on the development of antibiotic resistance.Materials and methods. 10 strains of melioidosis causative agent with typical cultural and morphological properties have been studied. The selection of variants resistant to benzalkonium chloride was carried out by successive passages on a dense nutrient medium with the addition of a disinfectant in increasing concentrations. The determination of sensitivity to benzalkonium chloride was performed through serial dilutions in agar, to antibacterial drugs from the groups of sulfonamides, β-lactams and tetracyclines – using disk diffusion method. Statistical processing of the obtained results was conducted with the help of the Microsoft Excel 2019 software. Arithmetic mean values and errors of mean values were calculated. The significance of differences between the parameters was determined applying Student’s t-test.Results and discussion. All parental strains showed a similar degree of resistance to the disinfectant compound and most of the strains – susceptibility to the antibiotics tested. Cultivation of B. pseudomallei strains on a nutrient medium with the addition of benzalkonium chloride led to an increase in resistance to this disinfectant. In addition, an increase in the level of resistance to all studied antibiotics was found. Statistical processing of the data collected revealed a significant correlation between the change in sensitivity to benzalkonium chloride and the emergence of resistance to amoxicillin/ clavulanic acid and ceftazidime. It was found that the causative agent of melioidosis, with a natural high susceptibility to benzalkonium chloride, has a high potential for developing resistance to this disinfectant compound, which is of practical importance in the development of disinfection regimens using quarternary ammonium compounds. For the first time, a direct correlation between a decrease in the sensitivity to benzalkonium chloride in B. pseudomallei and emergence of resistance to amoxicillin/clavulonic acid and ceftazidime has been demonstrated

Current epidemiological situation on Particularly Dangerous Mycoses around the World and Forecast of Its Development

The literature review focuses on epidemiological aspects of the spread of particularly dangerous mycoses across the world (coccidioidomycosis, histoplasmosis, blastomycosis, paracoccidioidomycosis). Forecast of morbidity rates for the next few years is provided too. Out of all endemic mycoses, coccidioidomycosis, endemic for North America regions, poses the most dangerous threat. In case of the infection, complications are most likely to arise, including the dissemination of the process in immunocompromised persons. Histoplasmosis is also classed as particularly dangerous mycosis. It affects both humans and animals. It is endemic for North, Central and South America, as well as Asia and Australia. The most studied endemic areas of infection with blastomycosis are in the territory of North America, while paracoccidioidomycosis is endemic for Latin America countries. Analysis of academic publications on particularly dangerous mycoses over the last three years testifies to the increase in their morbidity rates around the world. This situation is associated, primarily, with the increment in the number of immunocompromised subjects. An important stage in the improvement of the agent diagnostics is introduction of advanced methods for early diagnostics of mycoses, in particular, molecular-genetic and genome sequencing tools. It could also allow for the detection of patients beyond the limits of endemic foci

Ce-doped Li6Ln(BO3)3 (Ln = Y, Gd) Single crystals fibers grown by micro-pulling down method and luminescence properties

Ce3+-doped borate crystal fibers of Li6Gd(BO 3)3 (LGBO) and Li6Y(BO3)3 (LYBO) compositions are grown by the micro-pulling down (μ-PD) method for potential application in developing new neutron detectors. The ternary equilibrium diagram of Li2O-Gd2O3-B 2O3 is drawn and the preparations of homogeneous mixed LGBO and LYBO powders and growth conditions for single crystal fibers are discussed. Absorption, excitation and X-ray luminescence spectra are investigated. Absolute light yield derived from energy spectra and kinetic decay curves measured under α- and γ-scintillations of Ce 3+-doped LGBO and LYBO single crystal fibers is provided. © 2012 Elsevier B.V. All rights reserved

Infectious Diseases in the Americas Region that Are Relevant to the Global Surveillance and Control

The aim of the work was information-analytical assessment of the epidemiological situation on infectious diseases that are potentially or truly dangerous in terms of occurrence of emergencies of sanitary-epidemiological nature in the Region of Americas.Materials and methods. The study was based on the official reports of the WHO, the Pan American Health Organization, the Centers for Disease Control and Prevention, the national Ministries of Health, data from the ProMED information portal, the Global Network for the Epidemiology of Infectious Diseases, and published scientific papers.Results and discussion. By the model of the Americas, regional epidemiological features have been established, including the endemicity (enzooticity) of territories according to the most relevant nosological forms and the intensity of the epidemic process manifestations. It is shown that the main epidemiological risks in the countries of Central, South America and the Caribbean are associated with dengue, Zika, Chikungunya fevers characterized by a wide territorial dissemination and the ability to cause large-scale epidemic outbreaks, in the countries of North America – West Nile fever. Other infections of international concern include: cholera, that twice caused epidemics of imported origin during the seventh pandemic, which changed the structure of world morbidity; plague, manifested in an annual incidence, including with a complication by the pneumonic form, which determines an increased potential danger of anthropogenic spread; malaria, demonstrating an upward trend in morbidity and the number of intra-continental imported cases; yellow fever, characterized by the activation of natural foci and the expansion of the territories of potential pathogen transmission. The data obtained can serve as a basis for assessing the risks of infectious disease introduction from the American Region into safe territories, improving epidemiological forecasting and validity in making managerial decisions when conducting sanitary and anti-epidemic (preventive) measures

The energy consumption of trains in operation: simulation, a methodology for the analysis and influence of the driving style / Il consumo energetico di treni in esercizio: simulazione, metodologia di analisi ed influenza dello stile di condotta

The paper proposes an analysis methodology of energy consumptions in the railway field, presenting a comparison between an analytical calculation model and some measurements. It is hereafter assessed the influence of some parameters which characterise the travel diagrams of trains. The first part illustrates the analysis of the measured speed profile of a regional passenger train and of a TGV train covering a conventional line, with a high grade (the Torino-Modane), then introducing the comparison with the hypothetical profile obtained through simulation. Such comparison therefore allows deducing and quantifying the differences between the real and the simulated travel diagram. The latter employs completely the traction performances of the convoy and, therefore, features the smaller travel time on the considered line. The second part of this paper focuses the attention on the run of a freight train covering only one of the first sections of the same line, through the integration of the motion equation implemented on a spread sheet. In this part the analysis is carried on introducing important simplifications, as neglecting the effects of the line profile (rather flat in the considered stretch), in order to facilitate the analytical model. With such assumptions the influence on energy consumptions due to the scheduled travel diagram and to the driving style is evaluated. Special emphasis is given on the consumption connected to the braking stages and the relevant influence on the maintenance of brakes and wheel-sets, which has a direct economic impact for the transport operators. The role of innovative technological solutions is highlighted

Peculiarities of Burkholderia mallei and Burkholderia pseudomallei Identification Using Microbiological Analyzer Vitek 2 Compact 30

Automated Vitek 2 system, based on comparison of a biochemical profile of the studied bacterial cultures with the existing database, is widely used for B. pseudomallei and B. mallei identification in the laboratory practice.Objective of the study is to conduct extended phenotypic characterization of the strains of glanders and melioidosis causative agents, stored in the biobank of the Volgograd Research Anti-Plague Institute and analyze variations in their biochemical profiles, using Vitek 2 system.Materials and methods. Using Vitek 2 device, (bioMerieux, France) analyzed have been biochemical properties of 52 collection strains of B. pseudomallei and B. mallei grown on L-agar (Difco, USA) and trypticase-soy agar – TSA (HiMedia, India).Results and discussion. Most of the investigated strains (31 out of 40 B. pseudomallei and 8 of 12 B. mallei) have been identified with an acceptable probability for determining certain specie appurtenance, amounting to 90–99 %. The percentage of correct identification of B. pseudomallei and B. mallei is higher when strains are cultured on L-agar, than when on TSA. Due to the variability of the biochemical features, some strains have showed non-typical for its species results in certain tests (for B. pseudomallei strains – the absence of enzyme activity of β-N-acetyl-glucosaminidase, β-N-acetyl-galactosaminidase and ability to utilize D-cellobiose; for B. mallei strains – the absence of enzyme activity of L-proline-aryl-amidase and tyrosin-aryl-amidase, existence of glycin-aryl-amidase activity and ability to utilize sucrose, D-trehalose), which has led to their mal-identification. The probability of error diagnostics of microorganisms belonging to Burkholderia species necessitates up-dating of the database built into Vitek 2 analyzer as regards biochemical characteristics of the strains which have peculiar profiles

Results of Monitoring over the West Nile Fever Pathogen in the Territory of the Russian Federation in 2017. Forecast of Epidemic Situation Development in Russia in 2018

In Europe, in the epidemic season 2017, the incidence of West Nile fever did not exceed the index of the previous season. In the US and Canada, there was an increase in the incidence of cases. West Nile fever morbidity rates in the Russian Federation and in separate constituent entities were below the average long-term index and had the lowest value for the period since 2008. 41.6 % of WNF cases were imported to Russia from the distant countries. Analysis of the monitoring results indicated the circulation of WNF virus markers in carriers of the pathogen in 6 constituent entities of the Russian Federation, and the presence of IgG antibodies in healthy population cohorts in 24 RF entities. According to molecular-genetic typing of WNF virus samples from mosquito Culex modestus from the Volgograd Region, WNF virus genotype II was established. Forecasting of epidemiological situation development for the year 2018 does not rule out the possibility of local increase in WNF incidence in certain regions of Russia