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Pseudomonas aeruginosa, of medical, environmental, and industrial importance, depends on inorganic polyphosphate (poly P) for a wide range of functions, especially survival. Mutants of PAO1 lacking poly P kinase 1, PPK1, the enzyme responsible for most poly P synthesis in Escherichia coli and other bacteria, are defective in motility, quorum sensing, biofilm formation, and virulence. We describe here multiple defects in the ppk1 mutant PAOM5, including a striking compaction of the nucleoid, distortion of the cell envelope, lack of planktonic motility and exopolymer production, and susceptibility to the [beta]-Iactam antibiotic carbenicillin as well as desiccation. We propose that P. aeruginosa with reduced poly P levels undergoes ultrastructural changes that contribute to profound deficiencies in cellular functions. carbenicillin | exopolymer | motility | desiccation | nucleoid

Acute inflammation causes endothelial dysfunction, which is partly mediated by oxidant stress and inactivation of nitric oxide. The contribution of depletion of tetrahydrobiopterin (B[H.sub.4]), the cofactor required for nitric oxide generation, is unclear. In this randomized, double-blind, three-way crossover study, forearm blood flow (FBF) responses to ACh and glyceryltrinitrate (GTN) were measured before and 3.5 h after infusion of Escherichia coli endotoxin (LPS, 20 IU/kg iv) in eight healthy men. The effect of intra-arterial B[H.sub.4] (500 [micro]g/min), placebo, or vitamin C (24 mg/min) was studied on separate days 3.5 h after LPS infusion. In addition, human umbilical vein endothelial cells were incubated for 24 h with vitamin C and LPS. ACh and GTN caused dose-dependent forearm vasodilation. The FBF response to ACh, which was decreased by 23 [+ or -] 17% (P < 0.05) by LPS infusion, was restored to baseline reactivity by B[H.sub.4] and vitamin C. FBF responses to GTN were not affected by B[H.sub.4] or vitamin C. LPS increased leukocyte count, high-sensitivity C-reactive protein, IL-6, IL-1[beta], IFN-[gamma] monocyte chemoattractant protein-l, pulse rate, and body temperature and decreased platelet count and vitamin C concentration. Vitamin C increased forearm plasma concentration of B[H.sub.4] by 32% (P < 0.02). Incubation with LPS and vitamin C, but not LPS alone, increased intracellular B[H.sub.4] concentration in human umbilical vein endothelial cells. Impaired endothelial function during acute inflammation can be restored by B[H.sub.4] or vitamin C. Vitamin C may exert some of its salutary effects by increasing B[H.sub.4] concentration. inflammation; forearm blood flow; endothelial function; nitric oxide

Stool carriage of drug-resistant Escherichia coli in home-living residents of a rural community was examined. Carriage of nalidixic acid-resistant E. coli was associated with recent use of antimicrobial agents in [...]

AmpC [beta]-lactamase, altered porins, or both are usually responsible for cefoxitin resistance in Escherichia coil We examined the relative importance of each. We studied 18 strains of clinical isolates with [...]

Cattle are a natural reservoir of the food-borne pathogen Escherichia coli O157:H7. Therefore, strategies that reduce E. coli O157:H7 prior to slaughter will reduce human exposures to this virulent pathogen. When bacteria that can anaerobically respire on nitrate (e.g., E. coli) are exposed to chlorate, they die because the intracellular enzyme nitrate reductase converts nitrate to nitrite, but also co-metabolically reduces chlorate to cytotoxic chlorite. Because chlorate is bactericidal only against nitrate reductase-positive bacteria, it has been suggested that chlorate supplementation be used as a strategy to reduce E. coli O157:H7 populations in cattle prior to harvest. Cattle (n = 8) were fed a feedlot-style high-grain diet experimentally infected with three strains ofE. coli O157:H7. Cattle were given access to drinking water supplemented with 2.5 mM KN[O.sub.3] and 100 mM NaCl (controls; n = 4) or 2.5 mM KN[O.sub.3] and 100 mM NaCl[O.sub.3] (chlorate-treated; n = 4). Sodium chlorate treatment for 24 h reduced the population of all E. coli O157:H7 strains approximately two logs ([10.sup.4] to [10.sup.2]) in the rumen and three logs ([10.sup.6] to [10.sup.3]) in the feces. Chlorate treatment reduced total coliforms and generic E. coli from [10.sup.6] to [10.sup.4] in the rumen and by two logs throughout the rest of the gastrointestinal tract (ileum, cecum, colon, and rectum). Chlorate treatment reduced E. coli O157:H7 counts throughout the intestinal tract but did not alter total culturable anaerobic bacterial counts or the ruminal fermentation pattern. Therefore, it appears that chlorate supplementation is a viable potential strategy to reduce E. coli O157:H7 populations in cattle prior to harvest. Key Words: Escherichia coli O157:H7, Chlorate, Cattle

Diarrheogenic Escherichia coli isolates from 45 (73%) of 62 hospitalized patients were resistant to common antimicrobial drugs. Sixty-two percent were multidrug resistant, and >70% were resistant to trimethoprim-sulfamethoxazole and ampicillin. [...]

To the Editor: During the rainy season, from April to September 2003, 463 children [less than or equal to]15 years of age (median 10 months) with severe diarrhea were admitted [...]

ALF Ventures, a Salt Lake City-based joint venture by National Beef and DMV International, has consulted with the U.S. Food and Drug Administration (FDA) about its plans to market lactoferrin--an […]

Researchers at Los Alamos National Laboratory have created the first computer model of a key part of the E. coli ribosome. The model has applications in the development of new [...]