Comparison of MALDI-TOF MS, gene sequencing and the Vitek 2 for identification of seventy-three clinical isolates of enteropathogens

Objective: This study was performed to evaluate the analytical and practical performance of the matrixassisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) compared to the sequencing method and the Vitek 2 system for identification of enteropathogens in the clinical microbiology laboratory. Methods: Ten type strains and 73 clinical isolates of enteropathogens representing eight genera were analyzed by MALDI-TOF MS. All isolates were also characterized by gene sequencing allowing interpretation of the results from MALDI-TOF MS. In addition, MALDI-TOF MS was compared with the Vitek 2 system for the identification of ten isolates of Aeromonas and six of Salmonella . Results: As previously known, identification between Shigella and Escherichia coli is not possible to distinguish. MALDI-TOF MS produced the correct identifications for all other type strains and clinical isolates to the genus level. Fifteen Campylobacter jejuni, six Campylobacter coli, three Plesiomonas shigelloides , three Yersinia enterocolitica , two Clostridium difficile , one Vibrio parahaemolyticus , one Vibrio fluvialis , and one Vibrio cholera were all correctly identified to the species level. Genus and species identifications of ten Aeromonas and six Salmonella isolates by MALDI-TOF MS were consistent with those by the Vitek 2, but with much less cost and about ten times faster. Conclusion: This study demonstrates that MALDI-TOF MS is a powerful tool for fast, accurate and lowcost identification of enteropathogens in the clinical microbiology laboratory.