Susceptibility survey of piperacillin alone and in the presence of tazobactam

Abstract

Among 325 fresh isolates of bacteria from 153 hospital patients with serious infections, 142 were susceptible to piperacillin, 129 were resistant and a further 54 exhibited a marked inoculum effect Tazobactam restored the susceptibility of resistant isolates of Staphylococcus aureus and Staphylococcus epidermidis (except methicillin-resistant isolates), Haemophilus inftuenzae, Moraxella catarrhalis, Acinetobacter spp. and Bacteroides fragilis . Among 87 Enterobacteriaceae that were resistant to piperacillin, or showed an inoculum effect, 78 (89%) were restored to susceptibility by tazobactam. Pseudomonas spp. resistant to piperacillin were mostly resistant to the combination.