We carried out bacteriological and clinical studies on
tazobactam/piperacillin (TAZ/PIPC), a
combination drug of
piperacillin with the new
beta-lactamase inhibitor tazobactam, in various
infectious diseases in surgical field such as
intra-abdominal infections (
peritonitis and
intra-abdominal abscess), hepatobiliary
infections (
cholecystitis,
cholangitis and
hepatic abscess) and
secondary infections in
wound, etc. The total number of cases treated with the
combination drug was 164. Of these cases, 141 cases were assessable for clinical responses including 60 cases with
intra-abdominal infections, 38 cases with hepatobiliary
infections, and 43 cases with
secondary infections. Clinical efficacy rates of the
drug were 83.3% in cases with
intra-abdominal infections, 86.8% in cases with hepatobiliary
infections, and 95.3% in those with
secondary infections, hence the overall efficacy rate was 87.9%. In the cases from which
beta-lactamase producing strains were isolated, clinical efficacy rates were 84.8% in cases with
intra-abdominal infections, 84.6% in those with hepatobiliary
infections, and 96.2% in those with
secondary infections, hence the overall efficacy rate was 88.9%. Bacteriological efficacy rates were 92.9% in cases with
Gram-positive bacterial infections, 64.3% in those with
Gram-negative bacterial infections, and 100% in those with anaerobic
bacterial infections. Bacteriological efficacy rates were 84.2% in cases with single
bacterial infections and 56.5% in those with multi-
bacterial infections, and the overall bacteriological efficacy rate was 69.0%. In the cases of
infections with
beta-lactamase producing strains, bacteriological efficacy rates were 80.0% in cases with
Gram-positive bacterial infections, 75.0% in those with
Gram-negative bacterial infections, and 100% in those with anaerobic
bacterial infections. They were 82.6% in cases with single
bacterial infections and 57.9% in those with multi-
bacterial infections; the overall bacteriological efficacy rate was 67.2%. The bacterial eradication rate was 79.9% against all the isolates, and it was 79.2% against
beta-lactamase producing isolates. In addition, we compared the sensitivity distribution of the isolates to TAZ/PIPC with those to control drugs
piperacillin (PIPC),
cefotiam (CTM),
ceftazidime (CAZ),
sulbactam/
cefoperazone (SBT/CPZ). The MIC50 and MIC90 values of TAZ/PIPC against all strains were 3.13 micrograms/ml and 50 micrograms/ml, respectively. MIC50 values show that TAZ/PIPC was two times less effective than CAZ and SBT/CPZ but four times more effective than CTM; furthermore, from the MIC90 values, TAZ/PIPC was four times more effective than PIPC, CTM and CAZ. The MIC50 and MIC90 values of TAZ/PIPC against
beta-lactamase producing strains were 3.13 micrograms/ml and 50 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)