The type IV Aeromonas pilus (Tap) gene cluster is widely conserved in Aeromonas species

Nothing is known regarding the expression or function of the type IV Aeromonas pilus (Tap), which was recently identified following the cloning of a pilus biogenesis gene cluster (tapABCD). As a first step to determine the possible significance of Tap for Aeromonas virulence, the distribution of the tapA and tapD genes in hybridization group reference strains and clinical (n = 42) and environmental (n = 29) isolates was determined. Homologues of tapA and tapD were present in all strains tested. Hybridization with the tapA probe enabled us to differentiate between clinical and environmental isolates of A. veronii biovar sobria.