Role of the quorum-sensing system in biofilm formation and virulence of Aeromonas hydrophila

摘要

Aeromonas hydrophila?is a pathogen that causes disease in a wide range of homeothermic and poikilothermic hosts due to its multifactorial virulence. The production of many of these virulence determinants is associated with high cell density, a phenomenon that might be regulated by quorum sensing. The quorum sensing system regulates the expression of several virulence factors in a wide variety of pathogenic bacteria. To investigate the pathogenic role of quorum sensing system in?A. hydrophila, We constructed an?ahyI?mutant strain of a fish-clinical isolate YJ-1, named YJ-1?AhyI. Compared with the wild-type strain, the?ahyI?mutant strain exhibited a significant decrease of total extracellular virulent activity, and decreased in biofilm formation, intraperitoneal LD50?of?YJ-1?AhyI were more than 109?CFU, about 104?times higher than the parent strain. These results suggest that?A. hydrophila?is able to regulate its extracellular virulent factors and biofilm formation by quorum sensing systems, and indicate that disruption of quorum sensing could be a good alternative strategy to combat infections caused by?A. hydrophila.