Comparative in vitro activity of piperacillin, piperacillin–sulbactam and piperacillin-tazobactam against nosocomial pathogens isolated from intensive care patients

We investigated the antimicrobial activity of piperacillin-tazobactam versus piperacillin–sulbactam against common nosocomial pathogens ( n = 565) isolated from intensive care patients. For Gram-positive bacteria, antimicrobial susceptibilities to the two piperacillin–β-lactamase inhibitor combinations were almost identical. For Gram-negative bacteria, piperacillin–tazobactam exhibited greater activity against Escherichia coli and Proteus vulgaris than piperacillin–sulbactam. Both combinations, however, were equally effective against the other Enterobacteriaceae and Pseudomonas aeruginosa isolates. Piperacillin–sulbactam exhibited better antimicrobial activity against Acinetobacter baumannii. Our findings might prove important for the appropriate choice of antibiotic therapy with β-lactam–β-lactamase inhibitor combinations.