Multicenter in vitro comparison of piperacillin and nine other antibacterials against 1,629 clinical isolates

The antibacterial spectrum of activity of piperacillin was compared with that of other antibiotics against isolates of Escherichia coli, Enterobacter cloacae, Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pseudomonas cepacia, Pseudomonas maltophilia, Serratia marcescens, Enterococcus sp, Bacteroides fragilis, Bacteroides bivius, and Clostridium difficile, obtained from laboratories at hospitals in St. Louis, in Memphis, and in Newark, New Jersey. Of the 1,629 isolates tested, 91% were susceptible to piperacillin, 90% to mezlocillin, 87% to ticarcillin/clavulanate and imipenem, 83% to ceftazidime, 81% to cefoperazone, 80% to ciprofloxacin, 77% to ceftriaxone, 71% to aztreonam, and 51% to cefoxitin.