Angular momentum plays a central role in quantum mechanics, recurring in every length scale from the microscopic interactions of light and matter to the macroscopic behavior of superfluids. Vortex beams, carrying intrinsic orbital angular momentum (OAM), are now regularly generated with elementary particles such as photons and electrons. Thus far, the creation of a vortex beam of a nonelementary particle has never been demonstrated experimentally.
View Article and Find Full Text PDFBacterial pathogens inject virulence factors into host cells during bacterial infections using type III secretion systems. In enteropathogenic Escherichia coli, this system contains an external filament, formed by a self-oligomerizing protein called E. coli secreted protein A (EspA).
View Article and Find Full Text PDFDiagn Microbiol Infect Dis
July 1999
Enterococci have become important nosocomial pathogens, with Enterococcus faecalis and then Enterococcus faecium predominating. Because of the emergence of glycopeptide (vancomycin and teicoplanin) resistance in enterococci, laboratories have been required to screen for resistant strains and to identify them to the species level. This has resulted in the need for accurate identification of species less commonly associated with clinical infections, such as Enterococcus casseliflavus and Enterococcus gallinarum, which are inherently resistant to the glycopeptides.
View Article and Find Full Text PDFThe in vitro activity of and pathogen responses to sparfloxacin were compared with those of standard therapies for the treatment of patients with community-acquired pneumonia, complicated skin or skin-structure infections, urinary tract infections, acute bacterial exacerbations of chronic bronchitis, and acute maxillary sinusitis in 7 multicenter controlled trials in North America. Sparfloxacin was administered orally as a 400-mg loading dose followed by 200 mg once daily for up to 10 days. The bacteriologic efficacy of sparfloxacin (84% to 95%) was comparable to that of comparator drugs (77% to 100%).
View Article and Find Full Text PDFThis report summarizes the activities of quinupristin/dalfopristin (Q/D) and appropriate comparator antibiotics, including ciprofloxacin, erythromycin, gentamicin, rifampin, teicoplanin, and vancomycin, against selected gram-positive pathogens, including Enterococcus faecium, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus agalactiae, and Streptococcus pyogenes. The study pathogens were obtained from 2 sources: (1) clinical isolates taken from patients participating in Q/D worldwide Phase III comparative and noncomparative (emergency-use program) clinical trials; and (2) other isolates collected from the laboratories of 45 geographically distinct medical centers around the world. Q/D was highly active, with minimum inhibitory concentrations (MICs) < or = 1.
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