Antibiotics in acute cholecystitis

In 460 cholecystectomies performed for acute cholecystitis 215 (47%) positive gallbladder bile cultures were obtained. In 73% of emergency operations bacteria were recovered, in 48% of early operations (p less than 0.001) and in 29% of late operations (p less than 0.001). In vitro concentrations of 8-16 mcg/ml of ampicillin or cephalothin inhibited in most cases the growth of E. coli, Klebsiella and Enterococci, which comprised 75% of all strains isolated. One hour after intravenous infusion of 1 g ampicillin the mean serum level was 21 mcg/ml, the mean common duct level 16 mcg/ml and the mean gallbladder bile level 4.4 mcg/ml. In acute cholecystitis 2 g cephalothin gave mean concentrations of 14, 8, and 1.2 mcg/ml. Most of these patients had cystic duct obstruction both on intravenous cholegraphy and during operation. Control patients with patent cystic ducts who received ampicillin had mean gallbladder and common duct bile levels of 47 and 56 mcg/ml, and those receiving cephalothin 23 and 28 mcg/ml. It appears that adequate gallbladder bile concentrations of antibiotics are not attainable in acute cholecystitis because of the obstruction to the bile flow. The favourable results of prophylactic antibiotic treatment in reducing septic complications seem to depend more on adequate serum and tissue concentrations than on the concentration of antibiotics in the bile.