Typing of Streptococcus pyogenes strains using the phage profiling method.

We recently developed a method that allows fast differentiation between Streptococcus pyogenes (GAS) strains. The method named phage profiling (PP) is based on a simple assumption that a regular PCR reaction with Taq polymerase and relatively short elongation time is not able to yield long DNA fragment, such as ~40-50 kb integrated prophage. Only fragments without any integrated DNA or short fragments inserted between integration sites can be efficiently amplified. We designed primers that anneal upstream and downstream prophage integration sites, so in simple PCR reaction we can test if any additional DNA is integrated into particular site. Profiling of integrated elements can be used as rapid, high resolution typing method, with the resolution as high as PFGE and is excellent predictor of PFGE type.