Michael J. Schurr

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A comprehensive analysis of both the molecular genetic and phenotypic responses of any organism to the space flight environment has never been accomplished because of significant technological and logistical hurdles. Moreover, the effects of space flight on microbial pathogenicity and associated infectious disease risks have not been studied. The bacterial(More)
BACKGROUND A number of retrospective studies recently have been published concerning nonoperative management of minor liver injuries, with cumulative success rates greater than 95%. However, no prospective analysis that involves a large number of higher grade injuries has been reported. The current study was conducted to evaluate the safety of nonoperative(More)
Chronic respiratory infections with mucoid Pseudomonas aeruginosa are the leading cause of high mortality and morbidity in cystic fibrosis (CF). The initially colonizing strains are nonmucoid, but in the CF lung they invariably convert into the mucoid, exopolysaccharide alginate-overproducing form causing further deterioration and poor prognosis. Here we(More)
Conversion to a mucoid, exopolysaccharide alginate-overproducing phenotype in Pseudomonas aeruginosa is associated with chronic respiratory infections in cystic fibrosis. Mucoidy is caused by muc mutations that derepress the alternative sigma factor AlgU, which in turn activates alginate biosynthetic and ancillary regulatory genes. Here we report the(More)
Mucoid, mucA mutant Pseudomonas aeruginosa cause chronic lung infections in cystic fibrosis (CF) patients and are refractory to phagocytosis and antibiotics. Here we show that mucoid bacteria perish during anaerobic exposure to 15 mM nitrite (NO2) at pH 6.5, which mimics CF airway mucus. Killing required a pH lower than 7, implicating formation of nitrous(More)
OBJECTIVE Using CT to grade blunt splenic injuries frequently does not predict clinical outcome. This retrospective, blinded study evaluated whether revealing a traumatic pseudoaneurysm or frank hemorrhage on an initial CT examination can be used to predict the successful clinical outcome of patients managed without surgery. MATERIALS AND METHODS The(More)
AlgR controls numerous virulence factors in Pseudomonas aeruginosa, including alginate, hydrogen cyanide production, and type IV pilus-mediated twitching motility. In this study, the role of AlgR in biofilms was examined in continuous-flow and static biofilm assays. Strain PSL317 (DeltaalgR) produced one-third the biofilm biomass of wild-type strain PAO1.(More)
Nonoperative management of blunt splenic trauma is widely accepted; however, reported failure rates have ranged as high as 40%. There are few factors available to identify failures reliably. To characterize failures of nonoperative management better, we retrospectively reviewed 309 blunt splenic injuries treated at our level I trauma center over a 5-year(More)
Patients suffering from cystic fibrosis (CF) commonly harbor the important pathogen Pseudomonas aeruginosa in their airways. During chronic late-stage CF, P. aeruginosa is known to grow under reduced oxygen tension and is even capable of respiring anaerobically within the thickened airway mucus, at a pH of approximately 6.5. Therefore, proteins involved in(More)
Mucoid colony morphology is the result of the overproduction of the exopolysaccharide alginate and is considered to be a major pathogenic determinant expressed by Pseudomonas aeruginosa during chronic respiratory infections in cystic fibrosis. Conversion to mucoidy can be caused by mutations in the second or third gene of the stress-responsive system algU(More)