کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5545128 | 1555322 | 2017 | 8 صفحه PDF | دانلود رایگان |
- The ferric iron receptor gene B739_1208 of R. anatipestifer CH-1 was deleted and the mutant strain was deficient in iron utilization.
- The median lethal dose of R. anatipestifer CH-1ÎB739_1208 mutant was higher than that of wildtype (5.68Â ÃÂ 109vs 3.89Â ÃÂ 108).
- B739_1208 is a virulence factor of R. anatipestifer CH-1.
Riemerella anatipestifer is an important bacterial pathogen in ducks and causes heavy economic losses in the duck industry. However, the pathogensis of this bacterium is poorly understood. In this study, a putative outer membrane hemin receptor gene B739_1208 in R. anatipestifer CH-1 was deleted to determine the relationship between iron uptake and virulence. The R. anatipestifer CH-1ÎB739_1208 mutants grew significantly more slowly than the wild-type bacteria in TSB liquid medium. Further characterization revealed that the R. anatipestifer CH-1ÎB739_1208 mutants were deficient in iron uptake. Animal experiments indicated that the median lethal dose of the wild-type RA-CH-1 in ducklings was 3.89Â ÃÂ 108, whereas the median lethal dose of the R. anatipestifer CH-1ÎB739_1208 mutant in ducklings was 5.68Â ÃÂ 109. The median lethal dose of the complementation strain in ducklings was 9.84Â ÃÂ 108. Additional analysis indicated that bacterial loads in the blood, liver, and brain tissues in the R. anatipestifer CH-1ÎB739_1208-infected ducklings were significantly decreased compared to those in the wild-type R. anatipestifer CH-1 infected ducklings. In a duck co-infection model with R. anatipestifer CH-1 and R. anatipestifer CH-1ÎB739_1208, the R. anatipestifer CH-1B739_1208 mutant was outcompeted by the wild-type R. anatipestifer CH-1 in the blood (PÂ <Â 0.002), livers (PÂ <Â 0.001) and brains (PÂ <Â 0.001) of infected ducks, indicating that B739_1208 gene expression provided a competitive advantage in these organs. Our results demonstrate that the B739_1208 gene is a virulence factor in R. anatipestifer CH-1.
Journal: Veterinary Microbiology - Volume 201, March 2017, Pages 162-169