Pyridinium-2-azo-p-dimethylaniline chromophore, a new chromogenic cephalosporin for rapid beta-lactamase testing

A new chromogenic cephalosporin, pyridinium-2-azo-p-dimethylaniline chromophore, was evaluated for use in a rapid paper strip or tube test for the detection of beta-lactamases from a variety of microorganisms. A 1-min pyridinium-2-azo-p-dimethylaniline chromophore paper strip test was found to be a convenient and accurate method for the detection of beta-lactamase-producing strains of Haemophilus influenzae and Neisseria gonorrhoeae, although it could not be relied upon to detect beta-lactamases produced by staphylococci, enteric organisms, or Bacteroides fragilis.