LIBERATION OF ENDOTOXIN FROM ESCHERICHIA-COLI BY ADDITION OF ANTIBIOTICS

Abstract

The liberation of endotoxin from E. coli by the addition of antibiotics was investigated using a new method of Limulus test, i.e., dry up method. The addition of the bactericidal antibiotic, aminobenzylpenicillin or streptomycin sulfate, to the suspension of E. coli (.apprx. 106/ml) increased the concentration of endotoxin in the suspension .apprx. 8-9 times during the 3 h period. After antibiotic addition, the viable cell count decreased. The addition of the bacteriostatic antibiotic, tetracycline hydrochloride, also increased the endotoxin level, but this increase was mild. When polymyxin B sulfate was added there was no evident increase of the endotoxin level. The ability of polymyxin to suppress the elevation of endotoxin levels was shown when polymyxin in a concentration of > 2.5 .mu.g/ml was added to .apprx. 106/ml E. coli and was also shown by the combinational use of polymyxin with aminobenzylpenicillin or streptomycin. The endotoxin-inactivating ability of polymyxin was also shown when extracted lipopolysaccharide was used in place of viable cells. [If this endotoxin liberation occurs in patients treated with antibiotics, endotoxin-related complications may occur.].