Comparative Serum Bactericidal Activity against <i>Pseudomonas aeruginosa </i>of Six Antipseudomonal Agents

Abstract

Serum levels and serum bactericidal activities of six antipseudomonal agents were studied comparatively in 60 patients. Single intravenous doses of gentamicin (1.5 mg/kg), piperacillin (4 g), ceftazidime (1 g), imipenem (0.5 g), aztreonam (1 g), and ciprofloxacin (200 mg) were given over 30 min to 10 patients each, and serum samples were obtained 30 min, 1, 2, 3, 4, 6, 8 and 12 h after beginning the infusion. Serum bactericidal activity was determined by the broth microdilution method against 10 recent isolates of Pseudomonas aeruginosa. Mean peak serum levels were as follows: gentamicin 10.4 µg/ml, piperacillin 227.5 µg/ml, ceftazidime 43.5 µg/ml, imipenem 17.3 µg/ml, aztreonam 42.3 µg/ml, and ciprofloxacin 3.9 µg/ml. All agents demonstrated effective serum bactericidal activity (geometric mean titer > 1:2) at peak serum levels. Ceftazidime was by far the most potent compound with a mean titer of 1:46.5, followed by ciprofloxacin (1:17), imipenem (1:13.7), and aztreonam (1:13.4). Ceftazidime also showed the longest duration of activity with a mean titer of 1:5.1 at 4 h. Based on our results, ceftazidime appeared to be the most potent antipseudomonal agent, while gentamicin and piperacillin were the least effective.

Bactericidal effects of antimicrobial agents on epithelial cell-associated Pseudomonas aeruginosa

“…GM at 32 lg/ml killed over 99.9% of PAO1 associated with MDCK cells. CPFX had the strongest IPM and MEPM started to kill bacteria more rapidly than the other b-lactams, they required 9 h to finally kill 99.9% of the bacteria: the other b-lactams started to kill bacteria after incubation for 6-9 h. Dan et al [12] examined the MICs and MBCs of six antipseudomonal agents (including PIPC, CAZ, AZT, IPM, GM, and CPFX), their serum levels in patients, and serum bactericidal activity. In their study, CPFX had the strongest bactericidal activity, as measured by MBC, whereas CAZ was thought to have most potent serum bactericidal activity according to the serum level of the agents in the patients after a single intravenous dose.…”