We also examined whether the isoelectric point of purified cells of S. aureus, MSSA-B and MRSA-B, in comparison to the cells cultivated on MH agar was changed. The isoelectric point for MSSA and MRSA strains, agar-cultivated, was previously determined to be 3.4 [21]. The individual strains or the mixtures of the first five strains listed in Table 1 were gradually focused by CIEF. .In accordance with the previous report [21], only one narrow peak was detected in the migration time which corresponds to the isoelectric point of 3.4. Certainly, differences of the order of thousandths to hundredths of pI units between the individual strains of S. aureus can be assumed as described before [21].