The Bsp143I enzyme (Fermentas, Germany) was used to
digest the final PCR product of the spa gene. The procedures
were according to the instructions of Fermentas
Co.: 10 μL (~ 0.1-0.5 μg of DNA) of PCR reaction mixture
was added to 18 μL of nuclease-free water, 2 μL of 10X buffer
x Bsp143I buffer, and 2 μL of Bsp143I. The mixture was
mixed gently and spin down for a few seconds and incubated
at 37°C for four hours. Afterwards, Bsp143I was inactivated
by incubation at 65°C for 20 minutes. The OLIGO
software version 5 was also applied to detect the restriction
sites on the gene. The restriction sites of this enzyme
are outside the X region and it recognizes the “GATC” sequence.
The final products after Bsp143I digestion were
analyzed by electrophoresis on 1.5% gel. Finally, they were
compared with S. aureus strain 8325-4 on NCBI.