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Bioassay of teicoplanin in serum containing rifampin or a beta-lactam antibiotic

1989; Elsevier BV; Volume: 12; Issue: 5 Linguagem: Inglês

10.1016/0732-8893(89)90119-3

1879-0070

Michael T. Kenny, Jacqueline K. Dulworth, M A Brackman, Harry L. Torney, CAROLYN B. GIBSON, Annegret Hildebrand, Lana S. Weckbach, Joseph L. Staneck,

Pneumonia and Respiratory Infections

The purpose of this study was to develop bioassays for the measurement of teicoplanin in serum containing rifampin or a beta-lactam antibiotic. Use of rifampin-resistant Bacillus subtilis as indicator organism or pretreatment of the serum sample with Bacillus cereus penicillinase Type I (nafcillin, ticarcillin, mezlocillin) or Type II (cefazolin, cefuroxime, ceftazidime, ceftriaxone) effectively eliminated assay interference. Validation bioassays performed on two separate days utilizing triplicate coded serum samples containing 0 to 200 micrograms teicoplanin in combination with 40 micrograms/ml rifampin or 200 to 500 micrograms/ml beta-lactam showed no significant differences (p greater than 0.05, two-way analysis of variance) in analyte recovery between assay days. Regression analysis of each teicoplanin/rifampin or teicoplanin/beta-lactam data set yielded slope values of 0.92 to 1.01, intercept values of -0.45 to 0.84 and correlation coefficients of 0.9925 to 0.9990. Thus, serum teicoplanin can be quantitated accurately, precisely, and reproducibly in patients receiving concomitant rifampin or beta-lactam chemotherapy.