Prevalence of ESBLs in Acinetobacter baumannii isolated from intensive care unit (ICU) of Ghaem hospital, Mashhad, Iran

Acinetobacter baumannii is an important opportunistic pathogen that mainly infects critically patients in intensive care units (ICU). The production of plasmid-mediated extended-spectrum b-lactamases (ESBLs) is one of the most important mechanisms of resistance against b-lactam antibiotics. This study aimed to evaluate the prevalence of ESBLs in A. baumannii isolated from ICU of Ghaem hospital, Mashhad, Iran. A total of 140 A. baumannii isolates recovered from hospitalized patients in ICU of Ghaem hospital in Mashhad city from December 2014 to March 2015. Identification of A. baumannii isolates carried out using biochemical laboratory methods and then confirmed by OXA-51 PCR screening. Susceptibility testing performed using disk diffusion (Kirby-Bauer) method as recommended by CLSI guidelines. A. baumannii isolates screened for production of ESBLs using combination disk test. blaPER, blaGES, blaTEM, blaSHV, blaCTX, blaVEB and blaOXA-10 beta-lactamase genes detected using conventional PCR. The most antibacterial resistance was against cefuroxime (­99.3%) and colistin was the most effective antibiotic. None of the isolates were ESBL producer by combination disk test. However, results of PCR revealed that the prevalence of blaPER, blaGES and blaTEM genes were 7.1%, 4.3% and 27.1%, respectively. blaCTX, blaVEB, and blaOXA-10 were not found in any of isolates. According to the results, the high resistance was seen against selected antibiotics and the phenotypic tests are not sufficient alone for determination of ESBLs producer of A. baumannii isolates. So, molecular tests are also necessary for detection of these enzymes

Characterization of Pseudomonas aeruginosa isolates: Occurrence rates, antimicrobial susceptibility patterns, and molecular typing in the global SENTRY Antimicrobial Surveillance Program, 1997-1999

During 1997–1999, a total of 70,067 isolates (6631 Pseudomonas aeruginosa isolates) were analyzed in the SENTRY program by geographic region and body site of infection. The respiratory tract was the most common source of P. aeruginosa. P. aeruginosa isolation rates increased during the study interval. Europe was the only region to show a significant decline in β-lactam and aminoglycoside susceptibility rates. There was a reduction in the rates of susceptibility of Canadian isolates to imipenem and of Latin American isolates to meropenem. A total of 218 multidrug-resistant P. aeruginosa isolates (MDR-PSA; resistant to piperacillin, ceftazidime, imipenem, and gentamicin) were observed; MDR-PSA occurrence rates (percentages of all isolates) ranged from 8.2% (Latin America) to 0.9% (Canada). No antimicrobial inhibited >50% of MDR-PSA strains. Molecular characterization of selected, generally resistant strains was performed. Isolates showing unique ribogroups were found in Europe, Latin America, and the United States, but clonal spread was documented in several medical centers.A. C. Gales, R. N. Jones, J. Turnidge, R. Rennie, and R. Rampha

The Recent-Transmission of Mycobacterium tuberculosis Strains among Iranian and Afghan Relapse Cases: a DNA-fingerprinting using RFLP and spoligotyping

<p>Abstract</p> <p>Background</p> <p>Relapse of tuberculosis (TB) may develop as the result of reactivation of the endogenous primary infection, or as a result of a exogenous reinfection. This survey evaluated the rate of reactivation versus recent transmission among Iranian and Afghan relapse cases.</p> <p>Methods</p> <p>The sputum specimens were digested, examined microscopically for acid-fast bacilli, and inoculated into Löwenstein-Jensen slants by standard procedures. Thereafter, the susceptibility and identification tests were performed on culture positive specimens. Subsequently, the strains that were identified as <it>Mycobacterium tuberculosis </it>(258 isolates) were subjected to IS6110 restriction fragment length polymorphism (RFLP) and spoligotyping. Additional patient's information was collected for further epidemiological analysis. Patients whose isolates had identical genotyping patterns were considered a cluster with recent transmission episode.</p> <p>Results</p> <p>Out of 258 available isolates, 72(28%) had multi-drug resistant (MDR-TB) in ratio and 42 (16.2%) had other resistant. Notably, 38 of MDR-TB cases (52%) were isolated from Afghan patients. By IS6110-RFLP typing method, 65 patients (25%) were clustered in 29 clusters. In cluster cases, the intra-community transmissions between Iranian and Afghan patients were 41%. All MDR-TB patients in clusters had either Haarlem I or Beijing characteristic. The risk factors like sex, family history, close contact, living condition, PPD test result and site of TB infection were not associated with clustering. Although, the MDR-TB strains were more frequent in non-cluster cases (31%) than cluster one(18%) (P < 0.05). Majority of <it>M. tuberculosis </it>strains isolated from non-cluster cases were belong to EAI3 (51; 30%) and CASI(32;18.6%) superfamilies.</p> <p>Conclusion</p> <p>During the studied period, reactivation of a previous infection remain the more probable cause of recurrence. Although, the evidence of intra- community transmission between Iranian and Afghan TB cases, highlighted the impact of afghan immigrants in national tuberculosis control program (NTP) of Iran.</p

Neutronic analysis of nanofluids as a coolant in the Bushehr VVER - 1000 reactor

The main goal of this study was to perform the neutronic analysis of nanofluids as a coolant in reactor simulation. The variation of multiplication factor and thermal power have been investigated in the Bushehr VVER-1000 reactor core with using different nanofluids as coolant. In the applied analysis, water-based nanofluids containing various volume fractions of Al2O3, TiO2, CuO and Cu nanoparticles were used. The addition of different types and volume fractions of nanoparticles were found to have various effects on reactor neutronic characteristics. By using WIMS-D5 and CITATION code, the appropriate nanofluid with optimum volume percentage of nanoparticles was achieved. The results show that at low concentration (0.1% volume fraction) alumina is the optimum nanoparticle for normal reactor operation

Design of Dual-Band Double Negative Metamaterials

A dual-band artificial magnetic material and then a dual-band double-negative metamaterial structure based on symmetric spiral resonators are presented. An approximate analytical model is used for the initial design of the proposed structures. The electromagnetic parameters of the proposed metamaterial structure retrieved using an advanced parameter retrieval method based on the causality principle show its dual-band nature at microwave frequencies

Study of boron dilution phenomenon in the core and fuel assemblies of Bushehr VVER-1000 reactor in normal operating conditions

The spatial temperature distributions in fuel and coolant, results in appearing local changes in those elements densities in the reactor core, and also due to the complete solubility of boric acid in the coolant, there will be a direct correlation between the changes in the boron concentration and the coolant density. Because of the gradual reduction of boron concentration, first a local positive reactivity will be inserted into the core which will cause slight thermo-neutronic fluctuations in the reactor core. Of course, the trend of this process in the case of excessive reduction of the density of the coolant and evaporation of water (accident scenarios) will be reversed and subsequently the negative reactivity will be given to the system. With regard to the importance of this phenomenon, the spatial changes of boron concentration in the core and fuel assemblies of Bushehr VVER-1000 reactor have been examined. In line with this, by designing a complete thermo-neutronic cycle and by using CITATION, WIMS D-5 and COBRAN-EN codes, coolant temperature distribution and boron concentration will be calculated through this procedure, which first by using the output results of WIMS and CITATION codes, the thermal power of each fuel assembly will be calculated and finally, by linking these data to COBRA-EN code and using core and sub-channel analysis methods, the three-dimensional (3D) calculations of boron dilution will be obtained in the core as well as the fuel assemblies of the reactor

Semi 2D Modeling of the Horizontal Steam Generator PGV-1000 using the Relap5 Code

Developing a reliable thermal-hydraulic model of the steam generator is an essential process in the steady state and transient analysis for the Pressurized Water Reactor type of the Nuclear Power Plants. This paper provides a semi two dimensional thermal-hydraulic model of the PGV-1000 horizontal steam generator using the RELAP5 code. Applying the qualified nodalization and the cross-flow effects are some of the advantages in the present model. The obtained results from the RELAP5 steady state analysis showed a reasonable agreement with the Bushehr NPP Final Safety Analysis Reports (FSAR)

Molecular typing of Acinetobacter baumannii clinical strains by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR)

Acinetobacter baumannii is one of the most important causes of nosocomial infections. Because of the prevalence and recurrence of infections associated with A. baumannii that occur in different regions of hospitals, such as the ICU ward, is important to find the source of the infection by different techniques including molecular methods. This study aimed to determine A. baumannii isolates by ERIC-PCR. In this cross-sectional study, 80 A. baumannii isolates were retrieved from patients admitted to ICU, CCU, and post CCU wards of Ghaem hospital, Karaj, Iran. After detecting the isolates by phenotypic methods, standard biochemical tests were first used to identify the isolates and then API 20NE System kits (Biomerieux, France). The final confirmation was done by tracking the blaOXA-51 gene through PCR. Then, isolates were typed by the ERIC-PCR technique. The gel electrophoresis image was then analyzed by GEL compareII software and the relating dendrogram was depicted. The dendrogram obtained from the results of the study showed that the isolates were divided into 14 clusters using ERIC-PCR method. The present study showed that the ERIC-PCR technique is a useful tool for studying the genetic diversity of A. baumannii isolates. Also, A. baumannii isolates were rotating between ICU, CCU, and post CCU of Ghaem hospital, Karaj, Iran. And also, no specific pattern was observed in the distribution of the isolates from one ward to another. © 2019 Elsevier Inc

Performance of two--dimensional ultrasound shear wave elastography: reference values of normal liver stiffness in children

Background: Two-dimensional (2-D) shear wave elastography is a new sonographic elastography method for noninvasive measurement of liver stiffness. Objective: The aim of this study was to establish reference values of normal liver stiffness on 2-D shear wave elastography in children. Materials and methods: Two-dimensional shear wave elastography values were measured in 202 children with no liver disease from the neonatal period to puberty, who were divided into 4 age groups: newborns and infants, preschoolers, elementary school children and adolescents. We investigated the effects of age, depth of elastography measurement, transducer, number of measurements per child, liver size and Doppler parameters of hepatic blood flow on liver elasticity values. Results: The mean normal liver elasticity value in the study population was: 4.29±0.59 kilopascals (kPa). In neonates and infants, mean liver elasticity value was 4.63 (± 0.6) kPa, in preschoolers and elementary school children, 4.05 (± 0.57) kPa and 4.15 (± 0.52) kPa, respectively, and in adolescents, 4.39 (± 0.55) kPa. Values in neonates and infants as well as adolescents were significantly higher than in preschoolers and elementary school children (Kruskal-Wallis, P&lt;0.001; Mann-Whitney U tests, P&lt;0.05). There was no significant association between liver elasticity values and size of the right lobe or Doppler parameters of hepatic blood flow. Different depths and the number of elastography measurements had no effect on liver elasticity values. Conclusion: Two-dimensional shear wave elastography is achievable in a wide range of age in children. We established the reference values of normal liver stiffness on 2-D shear wave elastography in children. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature