The type 4 fimbrial subunit gene of Pasteurella multocida

Colonisation of host tissue by Gram- negative bacteria is facilitated by va rious adhesins, one of which is type 4 fimbriae (pili). These structures ha ve been associated with pathogenesis in several bacterial species, and have been shown to mediate colonisation of epithelial surfaces. Recently, type 4 fimbriae were identified and characterised from P. multocida strains A, B and D. The type 4 fimbrial subunit protein (PtfA) was identified as an 18- kDa protein which was isolated from whole membrane fractions. We report here the isolation and characterisation of the gene (ptfA) encodi ng the PtfA protein from P. multocida VP161 (serotype A:1). Part of the gen e was cloned on a 2-kb genomic DNA fragment. The complete ptfA gene was obt ained using inverse PCR. The gene and its flanking regions were characteris ed, and the deduced PtfA amino acid sequence was compared to type 4 subunit protein sequences from other bacterial species. The ptfA gene was amplifie d and sequenced from several P. multocida strains. Comparison of these sequ ences revealed variation within the type 4 subunit gene of P. multocida. (C ) 2000 Elsevier Science B.V. All rights reserved.