Report on the Misidentification of Vibrio cholera by VITEK Mass Spectrometer

Introduction: Vibrio cholera is the primary culprit of the cholera epidemic, causing gastrointestinal diseases. Non-O1/O139 strains of V. cholera spread into food and drink, causing food poisoning. The present study aimed to investigate the identification ability of the VITEK Mass Spectrometer (VITEK MS) for V. cholera strains. Case Presentation: Firstly, we utilized VITEK MS and VITEK 2 Compact, in addition to the serum agglutination test and 16S rRNA gene sequencing, to identify two V. cholera strains. The VITEK MS was employed to identify two clinical strains of V. cholera, and their protein spectra were compared. The VITEK MS incorrectly identified one strain as Vibrio mimicus with a confidence level of 99.9%; nevertheless, another strain was correctly identified as V. cholera with a confidence level of 99.9%. VITEK 2 Compact identified both strains as V. cholera at a confidence level of 97.0%. Serological tests revealed that the V. cholera strains were neither in the O1 nor O139 group. The 16S rRNA sequencing results confirmed the strains as V. cholera. The protein profiles of V. cholera and V. mimicus were observed to be similar, leading to the inability of the mass spectrometer to distinguish between them. Conclusions: Vibrio mimicus and V. cholera both belong to the Vibrio genus. The VITEK MS cannot completely differentiate between V. cholera and V. mimicus. For accurate identification, it is recommended to use biochemical serological tests by VITEK 2 Compact or serum.