The clinical and environmental spread and diversity of toxigenic Clostridium difficile diarrhea in the region of the Middle East.

Stool samples of 1822 hospitalized patients with nosocomial diarrhea and 100 environmental samples were collected at three teaching hospitals and PCR amplification of rRNA intergenic spacer regions (ISR) was conducted. Bacterial cytotoxicity was assayed by conducting three assays namely toxigenic culture on vero cells, stool cytotoxin, and enzyme immunoassay. ISR was carried out using two universal primers complementary to conserved regions in the 16S and 23S rRNA genes. It was found that the toxigenic culture, stool cytotoxin and enzyme immunoassay showed close rates of detection of toxigenic C. difficile, 124, 121, and 122 /1822 (6.8, 6.64., and 6.7%) respectively. In addition, 32 different ribotypes for toxigenic C. difficile were detected, 28 in clinical and 6 in environmental isolates. The predominant ribotypes from the clinical isolates were 13-15, 35.6%, of isolates. Ribotypes were associated with age, location of isolation, and severity of symptoms of clostridial diarrhea (P<0.05). Ribotypes 6-9 affected children only. The most common ribotype of C. difficile , no. 13, as well as ribotypes 16, 20, and 4 covered almost the whole range of severity of symptoms. Ribotypes 21-27, 1, 3, 6, 7, 9, 11, 14, and 19 caused mild-moderate CDAD symptoms while ribotypes 5, 10 8, 12, 15, 17, and 28 were dominantly of severe symptoms (P<0.05). Environmental isolates showed 17% toxigenic strains composed of 4 different ribotypes while ribotypes 5 was shared with clinical isolates. These findings showed that C. difficile associated with diarrhea were genetically diverse and linked to environmental strains

The clinical and environmental spread and diversity of toxigenic Clostridium difficile diarrhea in the region of the Middle East

Abstract Stool samples of 1822 hospitalized patients with nosocomial diarrhea and 100 environmental samples were collected at three teaching hospitals and PCR amplification of rRNA intergenic spacer regions (ISR) was conducted. Bacterial cytotoxicity was assayed by conducting three assays namely toxigenic culture on vero cells, stool cytotoxin, and enzyme immunoassay. ISR was carried out using two universal primers complementary to conserved regions in the 16S and 23S rRNA genes. It was found that the toxigenic culture, stool cytotoxin and enzyme immunoassay showed close rates of detection of toxigenic C. difficile, 124, 121, and 122 /1822 (6.8, 6.64., and 6.7%) respectively. In addition, 32 different ribotypes for toxigenic C. difficile were detected, 28 in clinical and 6 in environmental isolates. The predominant ribotypes from the clinical isolates were 13-15, 35.6%, of isolates. Ribotypes were associated with age, location of isolation, and severity of symptoms of clostridial diarrhea (P&lt;0.05). Ribotypes 6-9 affected children only. The most common ribotype of C. difficile , no. 13, as well as ribotypes 16, 20, and 4 covered almost the whole range of severity of symptoms. Ribotypes 21-27, 1, 3, 6, 7, 9, 11, 14, and 19 caused mild-moderate CDAD symptoms while ribotypes 5, 10 8, 12, 15, 17, and 28 were dominantly of severe symptoms (P&lt;0.05). Environmental isolates showed 17% toxigenic strains composed of 4 different ribotypes while ribotypes 5 was shared with clinical isolates. These findings showed that C. difficile associated with diarrhea were genetically diverse and linked to environmental strains

Salt Dependence of the Tribological Properties of a Surface-Grafted Weak Polycation in Aqueous Solution

The nanoscopic adhesive and frictional behaviour of end-grafted poly[2-(dimethyl amino)ethyl methacrylate] (PDMAEMA) films (brushes) in contact with gold- or PDMAEMA-coated atomic force microscope tips in potassium halide solutions with different concentrations up to 300 mM is a strong function of salt concentration. The conformation of the polymers in the brush layer is sensitive to salt concentration, which leads to large changes in adhesive forces and the contact mechanics at the tip–sample contact, with swollen brushes (which occur at low salt concentrations) yielding large areas of contact and friction–load plots that fit JKR behaviour, while collapsed brushes (which occur at high salt concentrations) yield sliding dominated by ploughing, with conformations in between fitting DMT mechanics. The relative effect of the different anions follows the Hofmeister series, with I − collapsing the brushes more than Br − and Cl − for the same salt concentration

The use of lysozyme to prepare biologically active chitooligomers

International audienceTwo types of crustacean commercial chitosans (CS1, CS2) were dissolved in lactic acid solutions, hydrolysed by lysozyme and finally fractioned by methanol solutions into two parts containing chito-oligomers (CS-O1, CS-O2). The antioxidant power and antimicrobial properties of both fractions were studied and compared with non-hydrolysed CS1 and CS2. The antioxidant properties were determined by the ferric ion reducing antioxidant power (FRAP) method while the bioactive properties were evaluated against a strain of Listeria monocytogenes. CS-O obtained from the solid fraction of the chito-oligomers solid fractions treated with 90% methanol showed the highest reducing power. Microbiological tests showed that CS-O exhibit higher antilisterial activity than CS

Series solution of a nonlinear ODE arising in magnetohydrodynamic by HPM-Padé technique

In this study, we investigate the magnetohydrodynamic (MHD) viscous flow due to a shrinking sheet by employing the homotopy perturbation method (HPM) and Pad approximation. The series solution of the governing nonlinear problem is developed. Generally, the truncated series solution is adequate only in a small region when the exact solution is not reached. We overcame this limitation by using the Pad techniques, which have the advantage in turning the polynomial approximation into a rational function, are applied to the series solution to improve the accuracy and enlarge the convergence domain. Comparison of the present solutions is made with the results obtained by other applied methods and excellent agreement is noted. © 2011 Elsevier Ltd. All rights reserved.Islamic Azad University, IAUB. Raftari is grateful to Islamic Azad University, Kermanshah branch for financial support through Research Project (The homotopy perturbation method for solving the system of magnetohydrodynamics (MHD) equations in unbounded domain), for completing this work. -

Solution of the MHD Falkner-Skan flow by Adomian decomposition method and Padé approximants

Purpose - The purpose of this work is to analytically examine the magnetohydrodynamic (MHD) Falkner-Skan flow. Design/methodology/approach - The series solution is obtained using the Adomian decomposition method (ADM) coupled with Padé approximants. Findings - Comparison of the present solutions is made with the results obtained by other applied methods and excellent agreement is noted. Originality/value - In this work, the MHD Falkner-Skan flow is examined analytically. The series solution is obtained using the ADM coupled with Padé approximants. Comparison of the present solutions is made with the results obtained by other applied methods and excellent agreement is noted. © Emerald Group Publishing Limited

Antimicrobial pattern and clonal dissemination of extended-spectrum beta-lactamase producing Klebsiella spp isolates

Problem statement: Gram-negative pathogens harboring ESBLs have caused numerous outbreaks of infections and are becoming an increasing therapeutic problem in many countries. The incidence of ESBL-producing strains among clinical isolates has been steadily increasing over the past years resulting in limitations of therapeutic option. The focus of this study was to examine the molecular epidemiology of ESBL-producing Klebsiella spp, investigate the susceptibility of Klebsiellae spp producing ESBLs towards non-beta-lactam antibiotics in the different seasons, identify the various clonal types of ESBL-producing K.pneumoniae and detect the dominant ESBL clonal types. Approach: Clinical isolates of Klebsiella spp were identified during the period March 2007-April 2008. ESBLs production identified by phenotypic and genotypic methods. MLST was performed for dissemination of ESBLs producing K. pneumoniae. Results: The findings showed that 51.6 of K.pneumoniae were produces ESBLs. 35.8, 21.2 and 38.7 of K. pneumoniae producing ESBLs were resistant to amikacin, ciprofloxacin and cotrimoxazol, respectively. It was found that 40 and 27.3 of K.oxytoca producing ESBLs were resistant to cotrimoxazol and amikacin, respectively. The findings reflected that ESBLs existed in 73 of K. oxytoca. The results showed that the frequency of blaSHV, blaTEM and blaCTX-M due to K.pneumoniae producing ESBLs were 87.5, 12.4 and 24.8, respectively. Of the eleven K. oxytoca producing ESBLs, 100 blaSHV were obtained. Based on the nucleotide variations of the five genetic loci, twenty-five different STs could be identified among thirty K.pneumoniae producing ESBLs isolates. Among the STs shared by multiple isolates, the most frequently encountered were 14, 16 and ST18. Conclusion: In conclusion, the percentage of K.oxytoca producing ESBLs was higher than K.pneumoniae producing ESBLs. Generally, K.penomoniae produces more ESBLs in winter and fall than in the other seasons. © 2010 Science Publications