TABLE 1.

In vitro activity of piperacillin-tazobactam and cefepime tested against 105 ESBL phenotype (NCCLS criteria) strains of E. coli and K. pneumoniae (SENTRY Antimicrobial Surveillance Program, 2000)

AgentOrganism (no. of strains)Cumulative % inhibited at MIC (mg/liter) of:% Susceptiblea
≤0.120.250.51248163264
Piperacillin-tazobactamE. coli (65)3.1b6.326.662.581.389.189.192.289.1
K. pneumoniae (40)0.02.512.535.047.562.572.580.062.5
CefepimeE. coli (65)49.263.178.684.689.293.898.510098.5
K. pneumoniae (40)7.512.537.562.582.592.592.595.092.5
  • a Susceptibility criteria of the NCCLS (24, 25) were used.

  • b Of the strains, 3.1% were inhibited at ≤0.5 mg/liter.