Vascular Permeability Factor of Pseudomonas aeruginosa

Abstract

The production of vascular permeability factor (PF) by certain strains of Pseudomonas aeruginosa has becen demonstrated in rabbits injected intradermally with culture filtrates followed by intravenous injection with Pontamine Sky Blue 6BX. The dose-response curve was found to be rectilinear when lesion diameters, within the range of 10 to 20 mm, were plotted against log dose. Thus, PF in test filtrates can be measured with reasonable accuracy by the concomitant testing of a reference PF. In contrast to the titers of PF obtained with Vibrio cholerae cultures, those with strains of P. aeruginosa were rather low. Thus far, PF has been demonstrated only in shallow still cultures of P. aeruginosa and not in shake cultures. A variety of commercial media were tested for the production of PF, but none was satisfactory. A synthetic medium that gave more reproducible and higher yields of PF was developed. Cultivation at 30 C generally gave higher yields of PF than at 37 C. PF was destroyed by heating at 60 C for 30 min or by digesting with trypsin or Pronase. Strains producing larger amounts of PF appeared to have greater virulence when inoculated onto the surface of burns in mice than those yielding little or no PF.

Correlation of proteolytic activity of Pseudomonas aeruginosa with site of isolation

“…facial isolates had modest proteolytic capacities, the two eye isolates were extremely proteolytic (average of 5.2 mm). This is not surprising, since proteases have been implicated in the destruction of corneal tissue and may contribute to the dermonecrosis in burn patients and the endothelial invasion in ecthyma gangrenosum (4,11). Elevated protease activity among P. aeruginosa isolates may thus enhance invasive potential.…”

Reduced virulence of Pseudomonas aeruginosa grown in the presence of benzalkonium chloride

“…However, the possibility that low levels of cell envelope-attached BC molecules may affect the virulence of the organism cannot be excluded. We are currently comparing the BC-resistant and BC-sensitive strains with regard to their capacity for production of extracellular substances, such as vascular permeability factor (9) and collagenase (5), both of which are thought to be active in the pathogenesis of P. aeruginosa infections. The inability of cells of the BC-resistant strain to act as complex antigens and provide protection against lethal doses of the BC-sensitive strain suggests biochemical differences between the two strains.…”

Enzyme-linked immunosorbent assay for detection of Pseudomonas aeruginosa Lipopolysaccharides

“…With strains possessing one or more of the 02, 05, or 016 antigens considered as a single serotype, a total of 11 serotypes were identified in the Albany area. Reference strains for these serotypes were grown in a synthetic medium, SM 11 (2), at 37°C for 18 h. The cultures were centrifuged, and the supernatants were passed through a 450-nm membrane filter (Millipore Corp., Bedford, Mass.). The filtrates were dialyzed against frequent changes of distilled water at 4°C for 48 h and then centrifuged to remove any insoluble matter.…”