Molecular typing of multidrug-resistant Salmonella Blockley outbreak isolates from Greece.

During 1998, a marked increase (35 cases) in human gastroenteritis due to Salmonella Blockley, a serotype rarely isolated from humans in the Western Hemisphere, was noted in Greece. The two dominant multidrug-resistance phenotypes (23 of the 29 isolates studied) were associated with two distinct DNA fingerprints, obtained by pulsed-field gel electrophoresis of genomic DNA

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

Behaviour of short columns subjected to cyclic shear displacements: Experimental results

In this paper we present the results of an experimental program on eight reinforced concrete columns subjected to constant axial load and reversed statically imposed displacements. The loading conditions simulated those of a doubly fixed column. The parameters tested were: (a) the shear ratio alpha(s) = M/Vh (alpha(s) = 1, 2 and 3), (b) the amount of the longitudinal reinforcement (rho(s) = 0.02, 0.04), (c) the amount of the transverse reinforcement (rho(w) = 0.012, 0.019), (d) the axial load ratio (nu = 0.3, 0.6), and (e) two different main reinforcement layouts (conventional and a combination of conventional and bi-diagonal reinforcement). One of the major objectives of the tests was to measure the strains of the reinforcement (longitudinal and transverse) and of the concrete along inclined force-paths. Conclusions are drawn regarding the seismic design of columns with low shear ratios. (c) 2006 Elsevier Ltd. All rights reserved

Behavior and ductility of reinforced concrete short columns using global truss model

The main results of an experimental program on eight full-scale reinforced concrete short columns are presented. The specimens were subjected to compression and cyclic reversed uniaxial shear displacements. The parameters investigated were the value of shear ratio, the ratios of longitudinal and transverse reinforcement, and the normalized axial force ratio. Two different layouts of main reinforcement were tested: conventional (longitudinal) and a combination of longitudinal and bidiagonal reinforcement. Columns with shear ratio equal to I were shown to behave in a particularly brittle manner The presence of bidiagonal reinforcement improved to some extent the ductility of the specimens, but not to the level required by current aseismic design. The relative performance of the specimens tested is evaluated according to various ductility criteria. A model for designing short columns is also presented