Piperacillin/Tazobactam: Evaluation of Its In vitro Activity against Bacteria Isolated in Two Brazilian Hospitals and an Overview of Its Antibacterial Activity, Pharmacokinetic Properties and Therapeutic Potential.
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 São 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% of the isolates tested, while imipenem was active against 91%, cefepime 77%, and ciprofloxacin 73%. Against Enterobacteriaceae (n=398), cefepime was more active than piperacillin/tazobactam (92% versus 88%). Klebsiella pneumoniae strains (n=95) presented low susceptibility to piperacillin/tazobactam (79%), ceftazidime (67%), and to cefepime (82%) indicating a high percentage of ESBL-producing strains. The most active compounds against this species were imipenem (100%) and ciprofloxacin (93%). Piperacillin/tazobactam was the most active compound 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%] > piperacillin/tazobactam [60%] > cefepime [56%] > ceftazidime [52%] > gentamicin [45%] > ciprofloxacin = aztreonam [42%]). Cefepime was the most active compound against P. aeruginosa (n=128, only 67%), followed by ceftazidime (64%), piperacillin/tazobactam (63%) and imipenem (59%). Only imipenem (91%) was active against more than 50% of the A. baumannii isolates (n=79) tested. Piperacillin/tazobactam was the second most active compound against A. baumannii (49%) and the most active against B. cepacia (91%). Our results demonstrated a high level of antimicrobial resistance in the hospitals evaluated, especially among nonenteric Gram-negative bacilli; and clonal dissemination of multiresistant strains. Piperacillin/tazobactam may contribute to the treatment of nosocomial infections in Brazil, however, some degree of resistance was detected in some species in the instance of frequent multiresistant bacteria in the tertiary level hospitals where the drug was evaluated.
Sader
HS
Special Laboratory of Clinical Microbiology, Federal University of São Paulo.
Ferreira
AT
Tosin
I
Gales
AC
Keim
LS
Carbadillo
JM
Mello
SJ
Tavares
W