Molecular Typing Methods for STEC

In order to investigate the relatedness of Shiga toxin-producing Escherichia coli STEC strains isolated from outbreaks or sporadic cases, traditional methods of strain typing, such as serotyping and bacteriophage typing, have been used. However, newer molecular typing methods have been recently introduced in many laboratories, which include plasmid fingerprinting (1 ), ribotyping (2 ), polymerase chain reaction (PCR)-based methods such as RAPD (randomamplified polymorphic DNA)-PCR (3 ), and AFLP (amplified fragment length polymorphism) (4 ), and analysis of chromosomal DNA restriction patterns by pulsed-field gel electrophoresis (PFGE) (5 ). In this chapter, we describe three types of method for investigating relatedness of STEC strains: PFGE, RAPDPCR, and AFLP.