Microbiological and molecular research of the resistance in gram-negative pathogens of infectious complications to carbapenem antibiotics, approaches to its combating

Departamentul de microbiologie, Universitatea Naţională de Medicină Memorială Pirogov, Vinnytsya, UcrainaRezumat Introducere. În zilele noastre, o provocare majoră și actuală în medicină reprezintă problema prevenirii complicațiilor infecțioase, cauzate de bacteriile gram-negative multi-rezistente la antibiotice. Rezistența emergentă a agenților patogeni predominanți, ca Acinetobacter baumannii, Enterobacteria, Pseudomonas aeruginosa, corespunde producției de metalic β-lactamază (MβL), hidrolizei carbapenemelor, fiind frecvent codificată de genele VIM. Material și metode. Pe parcursul anilor 2011-2016, au fost izolate tulpini clinice de microorganisme, anterior de inițierea terapiei antibacteriene, de la pacienți în stare critică (n=441) cu arsuri de gradul IIb și III. Au fost utilizate metode standard de identificare. Testarea sensibilității antimicrobiene la imipenem și meropenem a tulpinilor de A. baumannii, P. aeruginosa, P. mirabilis a fost efectuată conform normativelor ghidurilor EUCAST. Screening-ul pentru producția de MβL a fost realizat, utilizând testul Double Disk Synergy. Genele VIM în tulpinile izolate de bacterii au fost identificate molecular prin reacția de polimerizare în lanț în timp real. A fost studiată influența utilizării combinate a concentrațiilor inhibitorii sub-minime (sub-MIC) de antiseptic decamethoxinum (diclorură de 1,10-decametilen-bis (N, N-dimetil mentoxicarbonilmetil- amoniu) asupra sensibilității tulpinilor clinice la carbapeneme. Rezultate. Studiul de șase ani a relevat patogenii predominanți în complicațiile infecțioase: A. baumannii (n=220; 34,26%), P. aeruginosa (n=127; 19,78%) și P. mirabilis (n=34; 5,30%) dintre totalul de 642 de tulpini clinice, obținute de la pacienți cu arsuri, în stare critică. Rezistența la carbapenem a fost confirmată în 27,41% de tulpini izolate clinic dintre totalitatea de agenți patogeni înregistrați. Apariția rezistenței la imipenem și meropenem s-a constatat în tulpinile clinice de A. baumannii (n=111 și, respectiv, n=126), P. aeruginosa (n=43 și, respectiv, n=48) și P. mirabilis (n=1 și n=2, respectiv). Dintre acestea, rezistența fenotipică la carbapenem, asociată cu producerea de MβL, a fost demonstrată la A. baumannii (36,81%), P. aeruginosa (33,86%) și P. mirabilis (8,82%). Rezistența mediată de MβL s-a dovedit a fi legată de gena VIM în A. baumannii (1,36%), P. aeruginosa (4,72%), P. mirabilis (8,82%). A fost constatată recuperarea sensibilității bacteriilor gram-negative studiate la imipenem și meropenem de 3,09-7,07 ori, după ce a fost utilizat sub-MIC de decamethoxinum. De asemenea, după utilizarea sub-MIC de DCM în culturile izolate, a fost înregistrată dispariția genelor VIM, detectate, initial, prin PCR. Concluzie. Bacilii gram-negativi: A. baumannii (34,26%), P. aeruginosa (19,78%) și P. mirabilis (5,30%), cauzează frecvent complicații infecțioase la pacienții cu arsuri și dezvoltă rezistență la carbapeneme, asociată genelor VIM, care codifică MβL. Combinația sub-MIC de antiseptic decamethoxinum cu carbapeneme demonstrează în mod semnificativ eficacitatea, in vitro, împotriva bacteriilor gram-negative rezistente. Abstract Introduction. Nowadays, the problem of prevention of infectious complications, caused by multi-antibiotic-resistant opportunistic Gram-negative bacteria is of great importance and actuality in medicine. The emerging resistance of leading pathogens as Acinetobacter baumannii, Enterobacteria, Pseudomonas aeruginosa corresponds to the production of metallic-β-lactamase (MβL), hydrolysing carbapenems, frequently encoded by VIM gens. Material and methods. From critically ill patients (n=441) with 2ndb 3rd degree burns clinical strains of microorganisms had been isolated before antibiotic therapy in 2011-2016 years. They were identified accordingly to standard methods. The antimicrobial susceptibility testing to imipenem and meropenem was done in all received strains of A. baumannii, P. aeruginosa, P. mirabilis according to guidelines EUCAST expert rules. Screening for MβL production was done employing Double Disk Synergy Test. In isolated strains of bacteria the molecular identification of VIM gens, was carried out by real-time polymerase chain reaction. The influence of combined use of sub-minimal inhibitory concentrations (sub-MIC) of antiseptic decamethoxinum (1,10-dekametilen-bis (N,Ndimethyl mentoksikarbonilmetil)-ammonium dichloride) on the susceptibility of clinical strains to carbapenem antibiotics. Results. The six-year trial demonstrated that A. baumannii (n=220; 34.26%), P. aeruginosa (n=127; 19.78%) and P. mirabilis (n=34; 5.30%) were predominant causative agents of infection complications among total of 642 clinical strains, received from critical patients with burns. Carbapenem resistance was confirmed in 27.41% of clinical isolates of totally registered pathogens. The occurrence of resistance to imipenem and meropenem was found in clinical strains of A. baumannii (n=111 and n=126, respectively), P. aeruginosa (n=43 and n=48, respectively), P. mirabilis (n=1 and n=2, respectively). Among them the phenotypic resistance, related with production of MβL to carbapenems was proved in A. baumannii (36.81 %), P. aeruginosa (33.86%) and P. mirabilis (8.82%). The MβL-mediated resistance was proved to be related with VIM-gens in A. baumannii (1.36%), P. aeruginosa (4.72%), P. mirabilis (8.82%). There was found the retrieval of the susceptibility of studied Gram-negative bacteria to imipenem and meropenem in 3.09-7.07 times after sub-MIC of decamethoxinum had been used. We also registered the disappearance of VIM gens after the use of sub-MIC of DCM in cultures of those isolates, which primarily had been detected by the PCR. Conclusion. Gram-negative bacteria as A. baumannii (34.26%), P. aeruginosa (19.78%) and P. mirabilis (5.30%), frequently cause infection complications in patients with burns, and obtain resistance to carbapenems related with VIM genes, coding for MβL. The combination of sub-MIC of antiseptic decamethoxinum with carbapenems significantly reveals in vitro their effectiveness against resistant Gram-negative bacteria.https://stiinta.usmf.md/sites/default/files/2018-09/MJHS%20nr.3_2017.pd

The concept of special escrow accounts to improve mortgage housing loans in Russia

Purpose: The article aims to identify and evaluate the key determinants of improving mortgage lending in Russia. Increasing the participation of financial institutions in the application of escrow accounts is of paramount importance in terms of fine-tuning the process of improving mortgage lending in Russia. Design/Methodology/Approach: In order to further improve housing mortgage lending, it seems necessary: firstly, to identify new opportunities that contribute to the development of a system of interaction between credit and financial organizations and borrowers in terms of using the innovative functions of escrow accounts; secondly, to highlight the functions, during the application of which the increase in the efficiency of the escrow account mechanism will be optimal; thirdly, to formulate recommendations on the implementation of the necessary changes in the process of applying escrow accounts, taking into account the peculiarities of mortgage lending in Russia. Findings: To fully take into account the potential impact of special escrow accounts on the process of interaction between the lender and the borrower, an additional escrow account functionality was developed, aimed at improving mortgage lending. Practical Implications: The results of the study can be put into practice in order to expand the range of escrow account functions used in the process of mortgage lending in Russia. Originality/Value: The main contribution of this study is the emphasis on the need to introduce innovative approaches to increase the functionality of escrow accounts used in the process of mortgage lending in Russia.peer-reviewe

Deformation potentials for Δ1 minimum of conduction band of single crystals n-Ge

Deformation potentials eV and eV  for ∆1 minimum of conduction band of single crystals  n-Ge are defined on the basis of theory of the anisotropic scattering and experimental data of longitudinal piezo resistance for single crystals n-Ge for the case, when P||J||[100]. Pressure coefficients for ∆ 1 minimum under uniaxial pressure along crystallographic directions [100], [110] [111] and hydrostatic pressure have been calculated taking into account the given parameters. The results show that the inversion of (L1-∆1) type of absolute minimum in single crystals n-Ge can be implemented under hydrostatic and uniaxial pressures P||J||[100] Ñ– P||J||[110]

Mechanisms of electron scattering in uniaxially deformed n\textit{n}-Ge⟨Sb, Au⟩\text{Ge} \langle \text{Sb, Au}\rangle single crystals

Temperature dependencies for concentration and the Hall mobility of electrons for the $\textit{n}$-$\text{Ge} \langle \text{Sb}\rangle$ and \linebreak $\textit{n}$-$\text{Ge} \langle \text{Sb, Au}\rangle$ single crystals uniaxially deformed along the crystallographic directions [100] and [111] are obtained on the basis of piezo-Hall effect measurements. A deformation-induced increase of the Hall mobility of electrons for $\textit{n}$-$\text{Ge} \langle \text{Sb, Au}\rangle$ single crystals at the uniaxial pressure along the crystallographic direction [100] has been revealed. A comparison of the obtained experimental results with the corresponding theoretical calculations of temperature dependencies of the Hall mobility showed that the obtained effect occurs at the expense of the reduction probability of electron scattering on the fluctuational potential. Its amplitude depends on the tempe\-rature and on the value of the uniaxial pressure. It has also been shown that an increase of the Hall mobility for the $\textit{n}$-$\text{Ge} \langle \text{Sb, Au}\rangle$ single crystals uniaxially deformed along the crystallographic direction [111] with an increasing temperature turns out to be insignificant and is observed only for the uniaxial pressures $P<0.28$ GPa. A decrease of the Hall mobility of electrons at the expense of the deformational redistribution of electrons among the valleys of the germanium conduction band with different mobility should be taken into account in the present case. The Hall mobility magnitude for the uniaxially deformed $\textit{n}$-$\text{Ge} \langle \text{Sb}\rangle$ single crystals is determined only by the mechanisms of phonon scattering and we have not observed the effect of the growth of the Hall mobility with an increase of temperature or the magnitude of uniaxial pressure.Comment: 10 pages, 7 figure

The role of sorbents and probiotics in the prevention of structural-morphological disorders in mice with dysbiosis on the background of virus-bacterial infection

Interest in the study of probiotics has grown significantly in recent years. One of the reasons for such increased attention to this problem is the results of numerous experimental studies, which show the important role of individual representatives of the normal microbiota in the aetiology and pathogenesis of many infections and even somatic human diseases. However, the violation of microbial ecology, as a rule, is accompanied by pollution of the internal environment of the body with toxic compounds of both exogenous and endogenous nature, so enterosorbents are among main approaches of improving the normal microbiota.The experiments allowed to establish a pronounced hepatoprotective function of the sorbent “Smektovit”, which is manifested by a decrease in destructive changes that accompany the process of modelling viral and bacterial infections on the background of dysbiosis. In addition, the results of the presented studies showed the ability of probiotic “multiprobiotic Symbiter®” and sorbent “Smectovit” to reduce deep cytodestructive messages in the simulation of viral and bacterial infections at the rate of dysbiosis and normalization of immune responses, as they accompany such processes. At the same time, it is noted that the preventive effect of probiotics is more pronounced in the intestine, and sorbents – in the liver

Method of assessment of subcritical cracking of glass fiber reinforced composites

Об’єктом досліджень слугують процеси зародження та розвитку мікро- та макротріщин в об’ємі композиту і пружні динамічні поля, які при цьому виникають. Статтю присвячено створенню методологічних основ ефективного акустико-емісійного діагностування докритичного розтріскування таких матеріалів за зміною параметрів пружних хвиль, що породжуються різними механізмами руйнування.The object of this study are processes of nucleation and growth of micro- and macrocracks inside a composite material and the corresponding elastic dynamic fields. The paper is devoted to the development of the scientifically grounded methodological fundamentals for the effective acoustic emission diagnostics of subcritical crack dynamics of such materials incorporating the variation of the parameters of the elastic waves that are related to the different mechanisms of their generation

Water intrusion in underground structures

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references (p. 119-124).This thesis presents a study of the permissible groundwater infiltration rates in underground structures, the consequences of this leakage and the effectiveness of mitigation measures. Design guides and codes do not restrict, address or make clear recommendations for permissible inflows in underground space. Owners, with the help of engineers, typically make decisions based on costs or specifications from past projects without looking at consequences of excessive groundwater infiltration and mitigation costs. The Author has reviewed the published leakage rates for tunnels in comparison with current international standards. After examining over one-hundred case studies, the Author infers that water leakage is the principal damage causing degradation on tunnel linings. International standards for permissible leakage rates (transit tunnels) are consistent with class A definitions of CIRIA (1979) and are approximately 0.1-2 gpm/100,000 SF (0.05-1.2 Uday/SM). The most common cause of leakage (based on numerous case studies) in cast-in-place lining is due to cracks that develop from shrinkage of concrete during curing and to the inability of the structure to accommodate movements due to thermal changes. Individual sources of leakage may be allowable within the permissible rates, however can cause damage to tunnel structure and to the surrounding environment (consolidation and differential settlement). Spalling is one of most common structural damages due to groundwater infiltration. The presence of water can cause unpleasant stains, resulting in erosion and corrosion over time. Formation of icicles, ice and water ponding can affect public safety in a tunnel and jeopardize operations. To mitigate leakage in underground structures and tunnels one may control and/or eliminate the inflow.(cont.) Chemical grouting is one of the most common measures. However, its application has been unsuccessful in 43% of cases reported by ITA-AITES (2001). Inappropriate material selection for each particular application is major contributing factor for the lack of success. The Author focused this thesis on highway and rail tunnels, and established recommended permissible leakage rates for such underground structures based on international standards and experiences. These recommended rates can serve as guidelines for future tunnel design specifications or to compare recorded inflow rates with international standards.by Alex Nazarchuk.M.Eng