Patent ID: 7166442

Claim:
A method for detecting an antibiotic-inactivating factor produced by a test microorganism, comprising: a) admixing the test microorganism with an antibiotic for which inactivation is to be determined, a permeabilizing agent for the test microorganism present in a non-growth-inhibiting microorganism-permeabilizing effective amount, and a strain of microorganism with known susceptibility for said antibiotic to form an assay culture; b) incubating said assay culture under appropriate conditions and for a time sufficient to detect said antibiotic-inactivating factor; and c) detecting growth in the assay culture, whereby, significant growth of the strain of microorganism or a distortion in a zone of inhibition in the assay culture is indicative of production of antibiotic-inactivating factor by the test microorganism.