Differentiation of Staphylococcus Species by Polymerase Chain Reaction-Based DNA Fingerprinting

Genomic deoxyribonucleic acid (DNA) of Staphylococcus species was analyzed by polymerase chain reaction-based (PCR-based) DNA fingerprinting to distinguish between species. A total of 123 staphylococci isolated from bovine mammary secretions, and nine type strains representing eight species were evaluated. Amplified DNA fragments were categorized as either primary, secondary or variable fragments. Primary [optical density > 0.3 absorbance units (AU)] and secondary fragments (optical density > 0.12 AU) were observed in all isolates within a species. Infrequent DNA fragments were designated as variable fragments (optical density > 0.12 AU). Profiles were discrete and reproducible for each species. A simple identification scheme was developed based on the occurrence of primary and secondary DNA fragments for a species. A computer integrated scanning laser densitometer was utilized to store, retrieve, compare and evaluate DNA fingerprint profiles. This permitted rapid and accurate evaluation of staphylococcal isolates. Results of this study suggest that PCR-based DNA fingerprinting is suitable for typing Staphylococcus species of bovine origin. This technique could be of value to researchers and clinicians involved in the study of bacteria isolated from food, humans and animals.