Dendroside A (1) and dendronobilosides A and B (2 and 3), three new sesquiterpene glycosides, have been isolated from the stems of Dendrobium nobile, a plant used in Chinese traditional medicine. Their structures and stereochemistry were determined as 10beta,12,14-trihydroxyalloaromadendrane 14-O-beta-D-glucopyranoside (1), 10,12-dihydroxypicrotoxane 10,12-di-O-beta-D-glucopyranoside (2), and 6alpha,10,12-trihydroxypicrotoxane 10-O-beta-D-glucopyranoside (3), respectively, on the basis of spectroscopic and chemical methods. Quantum chemistry calculations were used in support of the structural determination of 1. Compounds 1 and 2 were found to stimulate the proliferation of murine T and B lymphocytes in vitro, while compound 3 showed inhibitory activity in this same assay.
e38 14th International Congress on Infectious Diseases (ICID) Abstracts done using standard disk diffusion method. Multidrug resistance was defined as resistance to 3 or more classes of antibiotics including aminoglycosides, antipseudomonal penicillins, carbapenems, cephalosporins, and quinolones. MDR isolates were tested for carbapenemase production using modified Hodge test. Phenotypic determination for metallo-beta-lactamase (MBL) production was done using combined disk (imipenem + EDTA) and two different types of double-disk synergy methods (imipenem + EDTA and ceftazidime + EDTA). Results: We studied 60 non-duplicate isolates of A. baumannii that were grown from patient specimens including blood, bone, wound, sputum, and other sources, obtained over a 12-month period in 2008-2009. Among these isolates, 65% were resistant to 3 or more classes of antibiotics meeting criteria for MDR organisms, and 50% showed reduced susceptibility to carbapenems. Modified Hodge test was positive in 19 (83%) of carbapenem-resistant isolates showing carbapenemase production. All MDR isolates were negative for metallo-betalactamase (MBL) production when phenotypically tested with double-disk synergy method, using imipenem + EDTA and ceftazidime + EDTA. These findings were similar when we tested with combined-disk synergy test using imipenem + EDTA. Conclusion: This study confirms that majority of the currently prevalent A. baumannii are multidrug-resistant organisms, and half of them are carbapenem resistant. Carbapenemase production appears to be the most common mechanism of carbapenem resistance by phenotype screening method. Since these isolates were negative for MBL phenotype, production of carbapenem hydrolyzing oxacillinase is the most likely mechanism of resistance.
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