Most previous studies of endotoxemia in human sepsis relied on LAL assays based on gelation that were only sensitive to 1 ng/ml or more of endotoxin. In the current experiment, P aeruginosa produced such low levels of endotoxemia that dogs dying of sepsis from this Gram-negative organism would have been LAL assay negative by the gelation method. buy ampicillin
The potency of bacterial endotoxins in the Limulus assay is dependent on both the source of the endotoxin and the method of preparation. The findings of this study could be explained if the LPS produced by P aeruginosa were very toxic in vivo but had only weak activity in the LAL assay. The in vivo activity of an endotoxin, however, has been shown to correlate with its potency in the LAL assay. Comparison of E coli and P aeruginosa endotoxins by Limulus assay have found them to be very similar in activity. Further, the strain of E coli and P aeruginosa used in this study had similar amounts of endotoxin per bacterium by our LAL assay. Lastly, it has been suggested that P aeruginosa LPS may be less, not more, toxic than the LPS produced by other Gram-negative bacteria. Recent studies, however, have found that the endotoxins of E coli and P aeruginosa are roughly equipotent in vivo.
Category: Pseudomonas aeruginosa
Tags: aeruginosa, endotoxin, sepsis, septic shock