Effects of Beta-Lactam Antibiotics on the Acetaldehyde-Metabolizing System in Germ-Free Rats

Effects of several beta-lactam antibioticson the acetaldehyde-metabolizing system were studied using germ-free rats. Administration of cefamandole(CMD) to the rats caused a decrease in liver mitochondrial low Km aldehyde dehydrogenaseactivity and an increase in blood acetaldehydelevel during ethanol metabolism, similar to the case in conventional rats. Oral administration of CMD produced a pronounced increase in blood acetaldehydelevel compared to the subcutaneous administration of the antibiotic. When the animals were given various beta-lactam antibioticssubcutaneously, only the antibioticshaving an N-methyltetrazolylthiomethyl group at the 3-position of the cephalosporinnucleus exhibited the disulfiram-like effects on the acetaldehyde-metabolizing system. The results indicate that intestinal bacteria do no participate in the development of the disulfiram-like reaction of several beta-lactam antibiotics.