Evaluation of the new DrySlide beta-lactamase test

Four hundred thirteen recent clinical isolates of Staphylococcus, Haemophilus, Moraxella, and Neisseria species were tested for beta-lactamase production using the Difco DrySlide beta-lactamase test. These results were compared with those of the BBL Cefinase reagent. Of the 413 isolates tested, 258 (62.5%) were beta-lactamase positive. There was 99.8% agreement between the two test methods; only one isolate of Staphylococcus aureus was DrySlide-negative and Cefinase-positive. The DrySlide beta-lactamase reagent is an accurate and convenient format for the evaluation of beta-lactamase activity in the clinical laboratory.