Rapid differentiation of bacteria using cyclic polypeptide antibiotics

Abstract From the Canadian patent

Abstract of the Disclosure Rapid differentiation between viable grampositive and gram-negative bacteria is accomplished with certain polypeptide antibiotics which are used in combination with a compound which is normally reducible by the bacteria, The antibiotics selectively inhibit the reduction of the reducible compound by gram-positive bacteria but do not substantially affect the reducing capacity of the gramnegative bacteria. The particular antibiotics useful are cyclic polypeptides which affect the function of the cytoplasmic membrane of bacteria. A particular polypeptide antibiotic, polymixin B, will distinguish Proteus bacteria from other gram-negative genera.