Multipoint microbiological assay for detecting beta-lactamase.

A multipoint microbiological assay for determining beta-lactamase production by clinical isolates of bacteria was evaluated. With strains of Haemophilus influenzae, Neisseria gonorrhoeae, and Branhamella catarrhalis there was excellent correlation between results obtained using this method and those obtained using the chromogenic cephalosporin reference method. The multipoint method is an inexpensive yet reliable adjunct to conventional susceptibility testing methods.