Abstract

Pulsed field gel electrophoresis (PFGE) is widely used as an epidemiological tool for the typing and identification of bacterial strains. In contrast, Matrix-Assisted Laser Desorption Ionisation/Time-of-Flight Mass Spectrometry (MALDI-TOF MS) offers a new and promising approach to rapid identification and differentiation of bacterial strains. 30 Vibrio strains were isolated from two wastewater treatment plants from Agadir (14 V. cholerae non-O1, 10 V. alginolyticus, 5 V. fluvialis and one strain of V. metschnikovii) identified by Vitek 2 system (bioMérieux). 50% of all isolates are susceptible to all antibiotics tested. Differentiation of Vibrio strains was done using PFGE of NotI-digested genomic DNA. In addition MALDI-TOF-MS was performed. Out of the 30 strains of Vibrio examined in this study, 6 isolates could not be typed by PFGE and consistently appeared as a smear on the gel. In general, high genetic biodiversity among the Vibrio strains was found regardless to the isolation source. The results of MALDI TOF analysis show that the spectral profile, consisting of about 20 to 25 prominent peptide peaks masses ranging between 2 and 12 kDa. MALDI-TOF mass spectrometry could cluster the isolates from each species into the same pattern, whereas PFGE had lower discriminatory ability between species.