Evaluation of automated ribotyping system for characterization and identification of verocytotoxin-producing Escherichia coli isolated in Japan.

The usefulness of an automated ribotyping system (RiboPrinter) was evaluated for characterizing and identifying clinical isolates of 37 verocytotoxin-producing Escherichia coli (VTEC) strains and 16 non-VTEC strains. All strains were successfully ribotyped with satisfactory reproducibility and stability and characterized into 10 different ribogroups. All VTEC O157 strains were characterized into a specific ribogroup and correctly typed into the specific DuPont ID for VTEC O157:H7, while all of the non-VTEC O157 strains were clearly distinguished from VTEC O157. VTEC O26 and O111 strains, the most prevalent VTEC serotypes after O157, were also well characterized into specific ribogroups and identified. These results suggest that the RiboPrinter may have an advantage over other typing systems in that it can rapidly and easily discriminate VTEC from non-VTEC strains of the most prevalent VTEC serotypes in Japan, even though it provides a lesser degree of discrimination than pulsed-field gel electrophoresis (PFGE). With a hierarchical or sequential typing combining the RiboPrinter and PFGE, rapid and accurate typing can be achieved during an outbreak of VTEC, which may be useful in clinical and public health settings.