Application and evaluation of double digest selective label (DDSL) typing technique for Pseudomonas aeruginosa...

This study describes the application and evaluation of a recently developed fast bacterial typing technique (double digest selective label - DDSL) for hospital isolates of Pseudomonas aeruginosa. The protocol was based on a simultaneous double digestion/labelling reaction which was performed in a single reaction tube. After agarose gel separation selectively tagged restriction fragments were transferred using deonised water to a nylon membrane and visualized by a colour reaction. Starting from overnight culture, turn around time using this technique was only 8 h. The DDSL typing technique was applied for 77 hospital isolates. Among them 63 isolates were also typed by PFGE and the typing results were compared with those of DDSL. In conclusion, both techniques discriminated bacterial isolates into the same major clusters. DDSL proved to be as discriminatory as PFGE but much faster and easier to set up in a standard microbiological laboratory.