Alteration of the pilin adhesin of Pseudomonas aeruginosa PAO results in normal pilus biogenesis but a loss of adherence to human pneumocyte cells and decreased virulence in mice.
The disulfide loop domain of Pseudomonas aeruginosa PAO pilin was altered by insertion of a chloramphenicol acetyltransferase gene into the pilin gene so that the C-terminal nine amino acids were replaced with 11 new amino acids. The altered pilin gene was transferred into wild-type PAO by recombination, where it did not affect normal piliation as observed by transmission electron microscopy or change of sensitivity to f116, PO4, B9, and Pf1 pilus-specific bacteriophages. However, the binding to human pneumocyte A549 cells was markedly reduced when tested in an in vitro binding assay (2 to 6 bacteria bound per A549 cell for the mutant bacteria compared with 50 bacteria per A549 cell for the wild-type bacteria). Additionally, when susceptible A.BY/SnJ mice were challenged with wild-type P. aeruginosa PAO and with P. aeruginosa PAO-MP (altered pilin gene), a 50% lethal dose of 3 x 10(6) bacteria per mouse was observed for PAO-MP compared with 7 x 10(4) bacteria per mouse for PAO. Approximately 90 of the adherence capability of P. aeruginosa PAO is seemingly attributable to the C-terminal disulfide loop adherence domain of pili. The pilus adherence function contributes significantly to the virulence of P. aeruginosa PAO in the A.BY/SnJ mouse infection model.
Farinha
M A
MA
Department of Biological Sciences, University of Alberta, Edmonton, Canada.
Conway
B D
BD
Glasier
L M
LM
Ellert
N W
NW
Irvin
R T
RT
Sherburne
R
R
Paranchych
W
W
D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D000818:Animals; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000502:physiology*; D001483:Base Sequence; D005260:Female; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000502:physiology*; D006801:Humans; D037102:Lectins; D008168:Lung / Q000166:cytology / Q000382:microbiology*; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity*; D014774:Virulence
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D037102:Lectins; C038692:adhesin, Pseudomonas; D036781:Fimbriae Proteins