RESUMEN
Piperacillin/tazobactam is a highly active antibiotic against most clinically important species of Gram-negative and positive bacteria including anaerobes. It has never been used or tested against bacteria isolated in Brazil. In this article we report the in vitro activity of piperacillin/tazobactam against clinical isolates from two tertiary hospitals in Säo Paulo and Rio de Janeiro and review the evolving clinical literature. The study was performed before its commercialization in Brazil. Its activity was compared to that of several broad-spectrum antimicrobial agents commercially available in Brazil. Piperacillin/tazobactam was active against 83 percent of the isolates tested, while imipenem was active against 91 percent, cefepime 77 percent, and ciprofloxacin 73 percent. Against Enterobacteriaceae (n=398), cefepime was more active than piperacillin/tazobactam (92 percent versus 88 percent). Klebsiella pneumoniae strains (n=95) presented low susceptibility to piperacillin/tazobactam (79 percent)), ceftazidime (67 percent), and to cefepime (82 percent) indicating a high percentage of ESBL-producing strains. The most active compounds against this species were imipenem (100 percent) and ciprofloxacin (93 percent). Piperacillin/tazobactam was the most active compund against Gram-positive cocci (n=238; percentage of susceptibility rank order: piperacillin/tazobactam=imipenem>ciprofloxacin>cefepime) and the second most active against nonenteric Gram-negative bacilli (n=250, rank order: imipenem [72 percent]>piperacillin/tazobactam [60 percent]>cefepime [56 percent]>ceftazidime [52 percent]>gentamicin [45 percent]>ciprofloxacin = aztreonam [42 percent}...