Isolation and characterization of fish Aeromonas hydrophila adhesins important for in vitro epithelial cell invasion

The molecular mechanisms involved in the invasion of Aeromonas hydrophila (strain PPD 134/91) into host cells were studied in vitro using a carp epithelial cell line. Bacterial fractions were extracted with potassium thiocyanate (KSCN) to investigate the adhesins involved. Two groups of adhesins were found. The major group was high molecular weight proteins with the largest component being a 43-kDa protein. Amino terminal sequence analysis indicated that this may have been an outer membrane porin. This supports previous suggestions that a 43-kDa outer membrane protein may be important in adhesion of a human isolate of A. hydrophila . The minor group of adhesins were low molecular weight proteins likely to be less effective in mediating bacterial adhesion and invasion into carp epithelial cells.