Novel PCR-restriction fragment length polymorphism analysis for rapid typing of staphylococcal cassette chromosome mec elements

Abstract

We developed a novel PCR-restriction fragment length polymorphism test for the ccrB gene by using HinfI and BsmI for rapid typing of staphylococcal cassette chromosome mec (SCCmec). When tested with reference strains and methicillin-resistant Staphylococcus aureus isolates, the method proved to be valid and useful for rapid identification of four SCCmec types, especially type IV.

FIG. 1.

Physical map of SCCmec structure showing the ccrB gene and restriction sites for PCR-RFLP analysis. (A) Genomic structure of SCCmec. Locations of the mec complex and ccr complex are illustrated. (B) Sequence of the ccrB gene amplified by PCR in this study. Thick arrows indicate the primers. H, HinfI; B, BsmI.

FIG. 2.

Agarose gel electrophoresis showing PCR-RFLP patterns of the 643-bp amplified ccrB gene fragment from reference MRSA strains of four SCCmec types digested by HinfI (left) and by HinfI and BsmI (right). Lanes: 1, HPV107; 2, NCTC10442; 3, BK2464; 4, N315; 5, ANS46; 6, 85/2082; 7, MW2; 8, JCSC4044; M, 100-bp ladder marker.