Evaluation of an acriflavine disk assay for differentiating Staphylococcus aureus from other staphylococci isolated from bovine milk

摘要

882 Staphylococcus isolates from bovine milk and 3 S. intermedius isolates from dogs were analysed using an acriflavine disk assay. For all isolates, haemolytic pattern, results of tube coagulase tests after 4 and 24 h of incubation, growth on acriflavine-supplemented media, results of an acriflavine disk assay, and results of an automated identification system were determined. 10μg of acriflavine/disk was determined to be the most appropriate concentration for the use in the assay. All 112 isolates identified as S. aureus by the automated identification system were resistant to this concentration of acriflavine, and only 1 of 236 isolates identified as non-S. aureus was resistant. There was substantial agreement between the acriflavine disk assay and the automated identification system. Agreement between results of determining haemolytic pattern and results of other diagnostic tests was only moderate. It is concluded that the acriflavine disk assay, using 10μg of acriflavine/disk, is a practical and accurate method for differentiating S. aureus from other Staphylococcus isolates.