Bap-dependent biofilm formation by pathogenic species of Staphylococcus: evidence of horizontal gene transfer?
The biofilm-associated protein (Bap) is a surface protein implicated in biofilm formation by Staphylococcus aureus isolated from chronic mastitis infections. The bap gene is carried in a putative composite transposon inserted in SaPIbov2, a mobile staphylococcal pathogenicity island. In this study, bap orthologue genes from several staphylococcal species, including Staphylococcus epidermidis, Staphylococcus chromogenes, Staphylococcus xylosus, Staphylococcus simulans and Staphylococcus hyicus, were identified, cloned and sequenced. Sequence analysis comparison of the bap gene from these species revealed a very high sequence similarity, suggesting the horizontal gene transfer of SaPIbov2 amongst them. However, sequence analyses of the flanking region revealed that the bap gene of these species was not contained in the SaPIbov2 pathogenicity island. Although they did not contain the icaADBC operon, all the coagulase-negative staphylococcal isolates harbouring bap were strong biofilm producers. Disruption of the bap gene in S. epidermidis abolished its capacity to form a biofilm, whereas heterologous complementation of a biofilm-negative strain of S. aureus with the Bap protein from S. epidermidis bestowed the capacity to form a biofilm on a polystyrene surface. Altogether, these results demonstrate that Bap orthologues from coagulase-negative staphylococci induce an alternative mechanism of biofilm formation that is independent of the PIA/PNAG exopolysaccharide.
Tormo
M Ángeles
MÁ
Departamento de Química, Bioquímica y Biología Molecular, Universidad Cardenal Herrera-CEU, 46113 Moncada, Valencia, Spain.
Knecht
Erwin
E
Instituto de Investigaciones Citológicas, FVIB, 46010 Valencia, Spain.
Götz
Friedrich
F
Mikrobielle Genetik, Universität Tübingen, D-72076 Tübingen, Germany.
Lasa
Iñigo
I
Instituto de Agrobiotecnología y Recursos Naturales, CSIC-Universidad Pública de Navarra, 31006 Pamplona, Navarra, Spain.
Penadés
José R
JR
Instituto Valenciano de Investigaciones Agrarias (IVIA), Carretera Náquera-Moncada Km 4,5, 46113 Moncada, Valencia, Spain.|Departamento de Química, Bioquímica y Biología Molecular, Universidad Cardenal Herrera-CEU, 46113 Moncada, Valencia, Spain.
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D022761:Gene Transfer, Horizontal; D008969:Molecular Sequence Data; D013211:Staphylococcus aureus / Q000472:pathogenicity / Q000502:physiology*
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; C425726:Bap protein, Staphylococcus aureus