Alpha-haemolysin, a possible virulence factor in Proteus morganii

Bacteriophage typing of Proteus mirabilis, Proteus vulgaris, and Proteus morganii.

A bacteriphage typing scheme for differentiating Proteus isolated from clinical specimens was developed. Twenty-one distinct patterns of lysis were seen when 15 bacteriophages isolated on 8 Proteus mirabilis, 1 P. vulgaris, and 1 P. morganii were used to type 162 of 189 (85.7%) P. mirabilis and P. vulgaris isolates. Seven phages isolated on 3 P. morganii were used to type 13 of 19 (68.4%) P. mo...

ZapA, a possible virulence factor from Proteus mirabilis exhibits broad protease substrate specificity.

The opportunistic bacterium Proteus mirabilis secretes a metalloprotease, ZapA, considered to be one of its virulence factors due to its IgA-degrading activity. However, the substrate specificity of this enzyme has not yet been fully characterized. In the present study we used fluorescent peptides derived from bioactive peptides and the oxidized beta-chain of insulin to determine the enzyme spe...

Properties of cephalosporinase from Proteus morganii.

The cephalosporin beta-lactamase (cephalosporinase) was purified from a strain of Proteus morganii which showed resistance to cephalosporins. The optimal pH was about 8.5, and the optimal temperature was 40 degrees C. The isoelectric point was 8.7 and the molecular weight was estimated to be about 41,000 from sodium dodecyl sulfate-acrylamide gel electrophoresis. The enzyme activity was inhibit...

Plasmids and Putative Virulence Characters in Proteus mirabilis

Swarming-coupled expression of the Proteus mirabilis hpmBA haemolysin operon.

The HpmA haemolysin toxin of Proteus mirabilis is encoded by the hpmBA locus and its production is upregulated co-ordinately with the synthesis and assembly of flagella during differentiation into hyperflagellated swarm cells. Primer extension identified a sigma(70) promoter upstream of hpmB that was upregulated during swarming. Northern blotting indicated that this promoter region was also req...