Effect of antibiotics and osmotic change on the release of endotoxin by bacteria retained on intravenous inline filters.

A study was conducted on the effects of two antibiotics (gentamicin and carbenicillin) and of a sudden change from an isotonic to a hypotonic solution on the release of endotoxin by three gram-negative bacteria(Esherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) growing on a 0.22-mum pore size membrane filter. During a 72-hour constant flow of sterile lactated Ringers's solution through the contaminated filters, no endotoxin was released into the filtrates as tested by the coagulation of Limulus amebocyte lysate. However, flushing the filters with carbenicillin or gentamicin killed the bacteria and caused the release of endotoxin into the filtrates. A sudden osmotic change (flushing the filter with water) did not kill the bacteria nor cause the release of endotoxin into the filtrate.