Comparison of the activity of antibiotic combinations in vitro with clinical outcome and resistance emergence in serious infection by Pseudomonas aeruginosa in non-neutropenic patients.
Techniques for demonstrating synergy in vitro were compared in testing different beta-lactam-aminoglycoside combinations against 30 isolates of Pseudomonas aeruginosa. Poor concordance was noted among the results from chequerboard and 6 h and 24 h time-kill methods. Comparison of in-vitro synergy results with clinical outcome in 14 patients with pseudomonas infection showed that antagonism in the 24 h time-kill method was the most reliable prognostic indicator of clinical and bacteriological outcome. Although more than 70% of patients were cured clinically with cefsulodin or ticarcillin with tobramycin or amikacin, pseudomonas resistant to the beta-lactam emerged in 7 of 14 patients (50%); of those seven, three had poor clinical outcome. The rationale of adding aminoglycoside to beta-lactams against P. aeruginosa to prevent emergence of resistance needs closer examination.
D000328:Adult; D000368:Aged; D000583:Amikacin / Q000494:pharmacology / Q000627:therapeutic use; D000617:Aminoglycosides / Q000494:pharmacology / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002441:Cefsulodin / Q000494:pharmacology / Q000627:therapeutic use; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010403:Penicillin Resistance; D011552:Pseudomonas Infections / Q000188:drug therapy*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013982:Ticarcillin / Q000494:pharmacology / Q000627:therapeutic use; D014031:Tobramycin / Q000494:pharmacology / Q000627:therapeutic use
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D000583:Amikacin; D013982:Ticarcillin; D002441:Cefsulodin; D014031:Tobramycin