Identification and characterization of a fimbrial gene cluster of Edwardsiella tarda expressing mannose-resistant hemagglutination

We determined the nucleotide sequence of a 8.6 kb DNA region containing etfA encoding a putative fimbrial major subunit from chromosomal DNA of Edwardsiella tarda KG8401 which expresses mannose-resistant hemagglutination (MRHA). This region contained three novel genes, etfBCD, at the downstream region of etfA. The deduced amino acid sequences of EtfABCD contained conserved fimbrial domains; fimbrial protein, fimbrial chaperone, fimbrial usher and fimbrial protein, respectively. Escherichia coli transformed with the cloned etf operon expressed MRHA and fimbriae that reacted with rabbit antiserum against the fimbrial major subunit of E. tarda, showing the implication of the fimbriae in the hemagglutination of E. tarda.