EVALUATION OF A COMMERCIAL MICROBIAL IDENTIFICATION SYSTEM BASED ON FATTY-ACID PROFILES FOR RAPID, ACCURATE IDENTIFICATION OF PLANT PATHOGENIC BACTERIA

Fatty acid profiles of 773 strains representing 25 taxa of plant pathogenic and related saprophytic bacteria were compared with two commercially available broad-spectrum libraries and one self-generated library based primarily on cultures from the National Collection of Plant Pathogenic Bacteria. The accuracy of identification at specific level was often 100%, although for some closely related species and infraspecific taxa accuracy was sometimes significantly less than this. The accuracy of identification of Xanthomonas campestris pathovars was much better than for Pseudomonas syringae pathovars. Almost all identifications were made within 24-48 h. Standardization of cultural conditions was essential. Hydroxy fatty acids were of great taxonomic value in classification of Gram-negative bacteria. Improved library development and standardization of cultural and analytical techniques will further increase the accuracy of identification. Fatty acid profiling offers a valuable rapid, accurate method for identification of many bacteria.