Detection of Streptococcus mutans in Plaque Samples by the Direct Fluorescent Antibody Test

Culture methods traditionally have been used to isolate and identify bacterial species in clinical specimens. Culture methods are difficult when the specimen is as bacteriologi-cally complex as dental plaque1 and when the organism in question, such as Strepto-coccus mutans, is present in modest numbers. The fluorescent antibody test (FAT) has been suggested as a potentially simpler method of detecting S mutans in plaque samples.2.3 In the most commonly described procedure, plaque is cultured in broth media and after growth occurs, smears are prepared and stained with fluorescein-conjugated anti-serums against the various S mutans sero-