Open AccessStructural and regulatory mutations in Vibrio parahaemolyticus type III secretion systems display variable effects on virulence
Author(s) -
Calder Thomas,
de Souza Santos Marcela,
Attah Victoria,
Klimko John,
Fernandez Jessie,
Salomon Dor,
Krachler AnneMarie,
Orth Kim
Publication year - 2014
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12619
Subject(s) - virulence , vibrio parahaemolyticus , biology , microbiology and biotechnology , type three secretion system , mutant , effector , secretion , flagellum , vibrio cholerae , gene , swarming motility , biofilm , virulence factor , bacteria , genetics , quorum sensing , biochemistry
The Gram‐negative bacterium, Vibrio parahaemolyticus, is a major cause of seafood‐derived food poisoning throughout the world. The pathogenicity of V. parahaemolyticus is attributed to several virulence factors, including two type III secretion systems (T3 SS ), T3 SS 1 and T3 SS 2. Herein, we compare the virulence of V. parahaemolyticus POR strains, which harbor a mutation in the T3 SS needle apparatus of either system, to V. parahaemolyticus CAB strains, which harbor mutations in positive transcriptional regulators of either system. These strains are derived from the clinical RIMD 2210633 strain. We demonstrate that each mutation affects the virulence of the bacterium in a different manner. POR and CAB strains exhibited similar levels of swarming motility and T3 SS effector production and secretion, but the CAB 3 and CAB 4 strains, which harbor a mutation in the T3 SS 2 master regulator gene, formed reduced biofilm growth under T3 SS 2 inducing conditions. Additionally, while the cytotoxicity of the POR and CAB strains was similar, the CAB 2 (T3 SS 1 regulatory mutant) strain was strikingly more invasive than the comparable POR 2 (T3 SS 1 structural mutant) strain. In summary, creating structural or regulatory mutations in either T3 SS 1 or T3 SS 2 causes differential downstream effects on other virulence systems. Understanding the biological differences of strains created from a clinical isolate is critical for interpreting and understanding the pathogenic nature of V. parahaemolyticus .