Phenotypic diversity of Edwardsiella tarda isolated from different origins

Aims: To evaluate the diversity of phenotypic characteristics among isolates of Edwardsiella tarda from various origins. Methods and results: A total of 10 E. tarda strains were investigated on biological characteristics including flagella formation, bacterial motility, biofilm formation, extracellular protein and plasmid profiles. All the E. tarda strains (including two previous recognized as nonflagellation strains) were proven to have an average of 1–7 peritrichous flagella with the precise number positively correlated with motility and biofilm formation. All the E. tarda strains exhibited similar protein profiles except ET2034, LMG2793 and ET080814, which lacked the three major bands of approximately 18, 21 and 55 kDa. E. tarda with the same geographic location shared similar plasmid profiles. Conclusions:  Edwardsiella tarda strains exhibited diversities in phenotypic characteristics that may be linked to differences in geographic location or host origin. In addition, the number of flagella is essential for bacterial motility and biofilm formation. Significance and Impact of the Study: This is the first report demonstrating the difference in flagella formation between E. tarda strains, which may broaden the understanding of flagellation trait at intra‐species level. Furthermore, evaluation of virulence‐associated characteristics can provide useful information for unveiling the diverse pathogenic mechanisms of E. tarda.