[Single-daily-dose treatment of ceftriaxone for biliary tract infections and bacterial counts in bile]

To evaluate the effects of ceftriaxone (CTRX) administered once daily, the biliary concentration of CTRX and daily changes in the bacterial count in bile from an indwelling T-tube were measured concomitantly. The effects on prophylaxis of postoperative infections after biliary tract surgery were also examined mainly due to clinical symptoms. The biliary CTRX levels increased rapidly and were sustained as high as 92.5-219 micrograms/ml in all patients even 24 hours after 2 g of CTRX was infused intravenously once daily. Five of 7 patients whose bile samples were positive for bacteria showed high CTRX levels in bile and almost no bacteria present after treatment. CTRX-sensitive bacteria eliminated 1 or 2 hours after the administration in response to the increase of biliary CTRX levels. The changes in bacteria count of bile may be closely related to CTRX antibiotic activity. As an antibiotic prophylaxis, other 18 patients with biliary diseases received intravenous infusion of 2 g of CTRX once daily for 5-7 days (mean 5.9 days). Thus, once-daily dose treatment of CTRX 2 g may have antibiotic effects on biliary infection and postoperative prophylaxis of biliary infections and it is indicated that the prolonged biliary levels of CTRX are essential for its efficacy.