Detection of metallo-beta-lactamase producing Pseudomonas aeruginosa using a modified IMP-lysate assay

Since the increasing prevalence of carbapenem-resistant Pseudomonas aeruginosa spp., accurate detection of metallo-β-lactamase (MBL) such as blaVIM type enzyme producing isolates became very important. However, phenotypic MBL detection methods previously reported are not highly sensitive or highly specific. This study aimed to evaluate the performance of a modified IMP-lysate test, the doubledisk- synergy-test (DDST) and the combined-disk-test (CDT) for detecting MBL blaVIM gene in P. aeruginosa. The reference technique was PCR molecular test. The study used 12 blaVIM2 producer isolates, 13 MBL-negative controls which included 4 imipenem-susceptible strains and 9 imipenemresistant strains harbouring blaSHV-2a genes collected from two Tunisian hospitals and P. aeruginosa ATCC27853 and P. aeruginosa COL-1 as negative and positive controls respectively. CDT showed 100% of sensitivity. The highest level of specificity was shown by IMP-lysate test (76.92%). To evaluate efficiencies of methods, the study noted that the highest Youden Index (YI) was shown by IMP-lysate method (0.7), followed by DDST (0.6) than CDT (0.2). Since MBL-Etest and PCR were expensive and not adaptable for extension use in clinical microbiology laboratories, a modified IMP-lysate MBL hydrolytic activity can be chosen by laboratories with limited resources as an inexpensive, simple, and accurate test to detect . P. aeruginosa producing blaVIM enzyme.Key words: Metallo-beta-lactamase, VIM, phenotypic detection, pseudomonas aeruginosa

Comparative evaluation of the antimicrobial activity of Citrullus colocynthis immature fruit and seed organic extracts

Gastrointestinal problems, dermatological, gynaecological and pulmonary infections produced by micro-organisms are widespread in the entire globe. The treatment of these infections is mainly based on the use of synthetic drugs which have lost, in recent years, their effectiveness, due to the development of resistant strains and the rise of opportunistic fungal infections. Tunisian traditional medicine is a potential source of new remedies namely, Citrullus colocynthis Schrad. (Cucurbitaceae). Lyophilized aqueous and organic extracts from immature fruits and seeds were screened for activity against gram-negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Vibrio parahaemolyticus and Vibrio alginolyticus) and gram-positive (Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes and Micrococcus luteus) bacteria and various Candida spp. (Candida glabrata, Candida albicans, Candida parapsilosis and Candida kreusei). Minimal inhibition concentrations (MICs) and minimal bactericidal/fungicidal  concentrations (MBCs/MFCs) were used to investigate the antimicrobial activity. Extracts from the two C. colocynthis Schrad. organs, at immature state, inhibited the growth of all the tested strains. The highest antibacterial effects were obtained against E. coli (MIC = 0.006 mg/ml) with the fruit methanol and the seed petroleum extracts. Regarding the anticandidal activity assessment, seed extracts showed the lowest results. This study demonstrated the broad spectrum antimicrobial activity of C. colocynthis immature fruit and seed extracts.Key words: Citrullus colocynthis Schrad, fruits, seeds, organic extracts, antibacterial, anticandidal

Paramètres agronomiques liés à la tolérance au sel chez le haricot (Phaseolus vulgaris L.)

Agronomical traits associated with salinity-tolerance in common bean (Phaseolus vulgaris L.). Identifying multiple agronomical parameters associated with salinity-tolerance is important for evaluating common bean (Phaseolus vulgaris L.) cultivars and improving their tolerance to salinity. Six cultivars were grown in soil, under glasshouse conditions and exposed to three salinity levels (control, 25 and 50 mM NaCl) to evaluate their tolerance using their biomass and the relative salt-susceptibility index: I.S.R.S. = D.R.B./I.I.S. (D.R.B.: relative biomass deficit and I.I.S.: salinity intensity index). On the other hand, a comparative field trial was conducted at four experimental stations of INRAT (Ariana, Oued Beja, Oued Meliz and Sejnane) during three consecutive years with sixteen cultivars to determine their grain yield stability, grain size and precocity. Results showed that tolerant cultivars are colour-seeded, early and presented yield stability and medium grain size. By contrast the susceptible cultivars are late, white-seeded and characterized by a less stable yield and small to medium grain size

In Vivo modulation of integrin linked kinase using transgenic mice

Alterations in glomerular podocyte cell-cell and cell-matrix contacts are key events in progressive glomerular failure. Integrin-linked kinase (ILK) has been implicated in podocyte cell matrix interaction and is induced in proteinuria. To evaluate ILK function in vivo, mice with a Cre-mediated podocyte-specific ILK inactivation were generated. These animals appeared normal at birth, but developed progressive focal segmental glomerulosclerosis and died in terminal renal failure. The first ultrastructural lesion seen at onset of albuminuria are glomerular basement membrane (GBM) alterations with a significant increase in true harmonic mean GBM thickness. Podocyte foot processes effacement and loss of slit diaphragm followed with progression to unselective proteinuria. No significant reduction of slit-membrane molecules (podocin and nephrin), key GBM components (fibronectin, laminins and collagen IV isoforms) or podocyte integrins could be observed at onset of proteinuria. However, alpha3-integrins were relocalized into a granular pattern along the GBM, consistent with altered integrin mediated matrix assembly in ILK-deficient podocytes. As the increased GBM thickness precedes structural podocyte lesions and key components of the GBM were expressed at comparable levels to controls, our data imply an essential role of ILK for the close interconnection of GBM structure and podocyte function

Effects of internal and external flow on the vibration characteristics of anisotropic cylindrical shells

General approach -- General theory -- Equations of motion -- The displacemnet functions -- Determination of the mass and stiffness matrices -- Elasticity matrix -- Stiffness and matrices for the whole shell in vacuo -- Free vibration -- Effects of compressible flow -- Mass, stiffness and damping matrices of the moving fluid -- Pressure fluctuations induced by internal flow -- Representation of pressure field at nodal points -- Mean sqare response -- Method of calculation and discussion