4.11 - RAPID ASSAY OF SOME NEPHROTOXIC ANTIBIOTICS AND THE ASSAY OF ANTIBIOTICS IN MIXTURES

Abstract

This chapter focuses on the need for rapid assay of some nephrotoxic antibiotics and the assay of antibiotics in mixtures for accurate assessment of renal failure. The general principle utilized is to effect selective inactivation of all but one antibiotic in a sample so that the remaining antibiotic may be assayed as though it were present alone. The reason for measuring each component separately is that in the agar diffusion method there may be large errors in attempting to measure total activity of a mixture of two antibiotics (A + B) and then deducing the activity of A as the difference between A + A and B, if A can be measured separately. Bacillus subtilis is used for the rapid assay of gentamicin, kanamycin, streptomycin, neomycin, and vancomycin, alone, or any one of these in the presence of one of the following: benzylpenicillin, phenoxymethylpenicillin, ampicillin, methicillin, oxacillin, cloxacillin, dicloxacillin, nafcillin, carbenicillin, cephalothin, cephaloridine, cephaloglycin, or cephalexin.