Epidemiological typing of Staphylococcus aureus by DNA restriction fragment length polymorphism of coa gene

Twenty one staphylococcus aureus isolates of bovine mastitic milk origin from herds at different locations were analysed for their coa gene products and RFLP patterns. One of the isolates was coa gene deficient whereas the rest revealed polymorphism in the coa gene. The isolates revealed three different types of coa gene products (600, 680 or 850 bp) and three distinct RFLP patterns were obtained with aluI digests of PCR products. Amplicons of 600 bp produced only one fragment of 300 bp (Pattern I), amplicons of 680 bp produced two fragments of 210 and 260 bp (pattern II) and amplicons of 850 bp produced 3 bands at 170, 290 and 390 bp (pattern III). It was concluded that not all the s. aureus isolates possessed the coa gene, the coa genotype was location-specific and this character of the isolates can be used in epidemiological investigations.