Characterization of Enterobacteria using MALDI-TOF mass spectrometry.

A method is proposed for the rapid classification of Gram-negative Enterobacteria using on-slide solubilization and trypsin digestion of proteins, followed by MALDI-TOF MS analysis. Peptides were identified from tryptic digests using microsequencing by tandem mass spectrometry and database searches. Proteins from the outer membrane family (OMP) were consistently identified in the Enterobacteria Escherichia coli, Enterobacter cloacae, Erwinia herbicola, and Salmonella typhimurium. Database searches indicate that these OMP peptides observed are unique to the Enterobacteria order.