Advanced Journal of Microbiology Research ISSN 2736-1756 Vol. 15 (1), pp. 001-007, January, 2021. © International Scholars Journals

Full Length Research Paper

Assessment of the ahyI gene affected biofilm formation, motility, extracellular virulence and the pathogenicity in a fish model of infection

Weihua Chu1*, Yan Jiang2, Liu Yongwang3 and Wei Zhu1

1Department of microbiology, School of Life Science and Technology, China Pharmaceutical University, Nanjing, P. R. China, 210009.

2Jiangsu Entry-Exit Inspection and Quarantine Buearu, Nanjing P. R. China, 210001.

3College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, P. R. China, 210095.

Accepted 18 November, 2020

Abstract

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.

Key words: Aeromonas hydrophila, quorum sensing, biofilm, virulence factors.