Pseudomonas aeruginosa LasA protease and corneal infections.
OBJECTIVE
A mutant strain of Pseudomonas aeruginosa deficient in LasA protease (staphylolytic protease) has been described as having reduced ocular virulence, suggesting that LasA is a major virulence factor. This study was undertaken to provide further genetic analysis of the role of P. aeruginosa LasA protease in ocular infections.


METHODS
LasA protease-deficient mutants of P. aeruginosa PAO1-V and ATCC 19660 were constructed by allelic replacement. Mutants and their respective wild type parent strains were evaluated for virulence and growth in the eye using mouse scarification and rabbit intrastromal injection models of keratitis.


RESULTS
LasA protease-deficient mutants of both strains were as virulent as wild type strains, growing to 4 to 6 log10 CFU/cornea and causing significant ocular pathology in the mouse (P > 0.42) and rabbit (P > 0.53).


CONCLUSIONS
These data show that LasA protease is not a major corneal virulence factor, suggesting that the main mechanism of corneal damage has yet to be definitively identified.
Alionte
L G
LG
Department of Immunology/Microbiology, Wayne State University School of Medicine, 540 E. Canfield Ave., Detroit, MI 48201, USA.
Cannon
B M
BM
White
C D
CD
Caballero
A R
AR
O'Callaghan
R J
RJ
Hobden
J A
JA
D000818:Animals; D001426:Bacterial Proteins; D015169:Colony Count, Microbial; D003319:Corneal Stroma / Q000382:microbiology* / Q000473:pathology; D003320:Corneal Ulcer / Q000382:microbiology* / Q000473:pathology; D015818:Eye Infections, Bacterial / Q000382:microbiology* / Q000473:pathology; D005260:Female; D008666:Metalloendopeptidases / Q000172:deficiency / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D011552:Pseudomonas Infections / Q000382:microbiology* / Q000473:pathology; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000302:isolation & purification / Q000472:pathogenicity*; D011817:Rabbits; D014774:Virulence
D001426:Bacterial Proteins; D008666:Metalloendopeptidases; C066371:staphylolytic protease