Comparative evaluation of an automated ribotyping instrument versus pulsed-field gel electrophoresis for epidemiological investigation of clinical isolates of bacteria

A collection of bacterial isolates were typed using the RiboPrinter(R) Micr obial Characterization System (Qualicon, Wilmington, DE, USA), an automated ribotyping system, and pulsed-field gel electrophoresis (PFGE). Grouping p atterns, discrimination, and typeability were compared. The collection cons isted of 411 isolates of bacteria from 32 medical centers. The isolates inc luded a total of 18 species (both Gram-positive and Gram-negative), coverin g the range of concern to a laboratory performing epidemiological investiga tions. The patterns of groups obtained by both typing systems were similar for all species examined. Ribotyping provided less discrimination than PFGE , especially for Serratia marcescens, and Pseudomonas aeruginosa. All strai ns were typed by the RiboPrinter, but 2.75% were not typeable by PFGE. The RiboPrinter(R) has proven to be a valuable primary typing method for a high -volume laboratory, even for those species for which it provides a lesser d egree of discrimination than PFGE. (C) 1999 Elsevier Science Inc.