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Postantibiotic effect (PAE). In this experiment, fixed inocula of Staphylococcus aureus and Pseudomonas aeruginosa are exposed to ticarcillin, imipenem,
and ciprofloxacin at a set concentration of four times the MIC. The organism and the antibiotic are then diluted 1,000-fold to a point where the antibiotic
concentration is far below the MIC of the organism. Growth suppression of S. aureus following exposure to the three drugs (PAE) occurs for approximately
2 hours. Growth suppression of P. aeruginosa, however, is only demonstrated for imipenem and ciprofloxacin. The β-lactam ticarcillin has no effect on the
growth of P. aeruginosa. (CFU, colony-forming unit; MIC, minimum inhibitory concentration.) (Data from Craig WA, Ebert SC. Killing and regrowth of
bacteria in vitro: A review. Scand J Infect Dis Suppl 1991;74:63-70.)
Source: Laboratory Tests to Direct Antimicrobial Pharmacotherapy, Pharmacotherapy: A Pathophysiologic Approach, 10e
Citation: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L. Pharmacotherapy: A Pathophysiologic Approach, 10e; 2017 Available
at: http://mhmedical.com/ Accessed: May 13, 2017
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