New insights into the epidemiology, pathogenesis and therapy of Pseudomonas aeruginosa infections

Immunoblot analysis of serological response to Pseudomonas aeruginosa septicaemia in man

The occurrence of an outbreak of Pseudomonas aeruginosa septicaemias on an oncology ward permitted an analysis of antibody responses in patients who were all orally exposed to the same source of infection. Seven patients became septicaemic. Serial serum samples were immunoblotted against the homologous strain. Responses were compared with those of 16 other patients with septicaemias caused by other strains and 10 healthy controls. All 18 survivors produced increasing IgG or IgA antibody, or both, against a 35,000 dalton band, whereas these antibodies were usually absent or fell in titre in the five fatal cases. These antibodies were also lacking in sera taken just before a patient became septicaemic. This band had the electrophoretic characteristics of the outer membrane porin protein F.

Pulmonary microvascular injury induced by Pseudomonas aeruginosa cytotoxin in isolated rabbit lungs

The effects of Pseudomonas aeruginosa cytotoxin on the pulmonary microvasculature were studied in blood-free, perfused, isolated rabbit lungs. Cytotoxin was administered to the recirculating Krebs Henseleit albumin (1%) buffer during two consecutive 30-min-perfusion phases (phases 1 and 2) at a concentration of 13 micrograms/ml, followed by a third perfusion phase (phase 3) without toxin. After perfusion phases 2 and 3, the capillary filtration coefficient (Kf,c) and vascular compliance were determined gravimetrically from two-step microvascular pressure increments under zero-flow conditions. Cytotoxin caused a continuous release of K+ and lactate dehydrogenase, which started within the first 5 min and amounted to about 50% of the total lung cellular K+ and 5 to 7% of the total lactate dehydrogenase by the end of the experiment. The toxin caused the continuous generation of prostaglandin I2, which was detectable in the perfusates of all perfusion phases at maximum values five times above the control values and which was measured in the bronchoalveolar lavage fluid at the end of the experiment. Thromboxane generation in toxin-treated lungs did not significantly exceed that of control lungs or of lungs with mechanically induced edema. Cytotoxin caused a gradual increase in pulmonary vascular resistance, to maximum values 2.5 times above the control, starting within 1 min; the increase was partially reversible after washout of the toxin. After a lag period of 20 to 30 min, the lungs gained weight, amounting to a mean gain of 9.1 g at the end of the experiments. After perfusion phases 2 and 3, an almost fourfold increase in Kf,c, which was not reversible after washout of the toxin, was measured, whereas the values of vascular compliance were not altered. We conclude that pseudomonal cytotoxin may be an important factor in the pathogenesis of prolonged microvascular injury, encountered in states of P. aeruginosa sepsis or acute lung failure with secondarily acquired P. aeruginosa pneumonia.