DISCRIMINATION OF STAPHYLOCOCCUS-AUREUS STRAINS BY PCR FOR R-RNA GENESPACER SIZE POLYMORPHISM AND COMPARISON TO SMAI MACRORESTRICTION PATTERNS

The size polymorphism of the internal spacer between the 16 S and the 23 S r-RNA genes was studied in S. aureus with the aid of PCR. The pat terns of corresponding PCR products were compared with Smal-generated macrorestriction patterns for definite propagating strains of S. aureu s typing phages, for strains with phage pattern 29, phage-group II pat terns, phage pattern 94, 96, phage pattern 95 and epidemic methicillin -resistant strains (MRSA). The spacer length polymorphism did not prov e to be as discriminative as genomic DNA fragment patterns. However, a s shown for S. aureus with phage patterns 29; group II; 94, 96; 95 and also for 4 out of 6 epidemic MRSA, unique patterns of r-RNA gene spac ers probably indicate a relatedness among strains which is also sugges ted by Smal macrorestriction patterns.