Identification of Plesiomonas spp.: serological and MALDI-TOF MS methods.

Biochemical and serological profiles of isolates of Plesiomonas shigelloides were assayed using standard procedures in isolates from various clinical samples. Seventy-four isolates, including P. shigelloides type strain, were further characterized by MALDI-TOF MS using 3-methoxy-4-hydroxycinnamic acid as matrix. Multiple ions in the 3- to 12-kDa mass range were found in the spectra of each strain, from which the "species-identifying" unique biomarker ions were identified. After creating the species-specific patterns, a spectral database was generated for reliable, rapid, reproducible and accurate identification of Plesiomonas strains. The classical strain description (biochemical and serological) was thus complemented with the metabolic (proteomic) characterization.