Second multicenter study of the in vitro susceptibility to piperacillin-tazobactam

A study was conducted in 1999 on the activity of piperacillin-tazobactam on 1349 strains collected in a Spanish multicenter study involving 10 hospitals. A total of 897 Gram-negative bacteria of the following genuses were collected: Escherichia coli (169), Klebsiella spp. (112), Pseudomonas spp. (122), Enterobacter spp. (92), Serratia spp. (44), Citrobacter spp. (37), Proteus spp. (114), Morganella spp. (49), Acinetobacter spp. (47), Stenotrophomonas spp. (47), Haemophilus spp. (45), Moraxella spp. (19). The Gram-positive bacteria included Staphylococcus aureus (116), Streptococcus pneumoniae (92), and Enterococcus spp. (114). Piperacillin-tazobactam activity against different anaerobic bacteria was also determined: Bacteroides spp. (88), Clostridium spp. (25), Prevotella spp. (5), Fusobacterium spp. (3) and Peptosteptococcus spp. (9). The piperacillin-tazobactam combination was found to maintain its activity against the isolated microorganisms with regard to the previous study.