Type VI secretion system mutations reduced competitive fitness of classical Vibrio cholerae biotype

• Published in: Nature communications Vol. 12; no. 1; p. 6457
• Main Authors: Kostiuk, Benjamin, Santoriello, Francis J, Diaz-Satizabal, Laura, Bisaro, Fabiana, Lee, Kyung-Jo, Dhody, Anna N, Provenzano, Daniele, Unterweger, Daniel, Pukatzki, Stefan
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 09.11.2021; Nature Publishing Group UK; Nature Portfolio
• Subjects: Bacteria; Cholera; Competition; Gram-negative bacteria; Microorganisms; Mutation; Mutation - genetics; Pandemics; Secretion; Type VI Secretion Systems - genetics; Type VI Secretion Systems - physiology; Vibrio cholerae; Vibrio cholerae - genetics; Vibrio cholerae - physiology; Waterborne diseases
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-26847-y

The gram-negative bacterium Vibrio cholerae is the causative agent of the diarrhoeal disease cholera and is responsible for seven recorded pandemics. Several factors are postulated to have led to the decline of 6th pandemic classical strains and the rise of El Tor biotype V. cholerae, establishing the current 7th pandemic. We investigated the ability of classical V. cholerae of the 2nd and 6th pandemics to engage their type six secretion system (T6SS) in microbial competition against non-pandemic and 7th pandemic strains. We report that classical V. cholerae underwent sequential mutations in T6SS genetic determinants that initially exposed 2nd pandemic strains to microbial attack by non-pandemic strains and subsequently caused 6th pandemic strains to become vulnerable to El Tor biotype V. cholerae intraspecific competition. The chronology of these T6SS-debilitating mutations agrees with the decline of 6th pandemic classical strains and the emergence of 7th pandemic El Tor V. cholerae.