title: Quorum quenching bacteria Bacillus sp. QSI-1 protect zebrafish (Danio rerio) from Aeromonas hydrophila infection.
abstract: Quorum Sensing (QS) is a bacterial regulatory mechanism, which is responsible for controlling the expression of various biological macromolecules such as the virulence factors in a cell density-dependent manner. Disruption of the QS system of pathogens has been proposed as a new anti-infective strategy. Biodegradation of AHLs proves to be an efficient way to interrupt QS, since AHLs are the main family of QS autoinducers used in Gram negative bacteria. In this study, the effect of Bacillus sp. QSI-1 as an efficient quorum quencher on virulence factors production and biofilm formation of fish pathogen Aeromonas hydrophila was investigated. QSI-1 reduced the accumulation of AHLs but did not affect the growth of A. hydrophila YJ-1 when cocultured. In the result, the supernatant of QSI-1 showed significant inhibition of protease production (83.9%), hemolytic activity (77.6%) and biofilm formation (77.3%) in YJ-1. In biocontrol experiment, QSI-1 significantly reduced the pathogenicity of A. hydrophila strain YJ-1 in zebrafish (Danio rerio). The fish fed with QSI-1 was observed to have a relative percentage survival of 80.8%. Our results indicate that AHLs degrading bacteria should be considered as an alternative for antibiotics in aquaculture for the biocontrol of bacterial fish diseases.
authors: Department of Pharmaceutical Microbiology, China Pharmaceutical University, Nanjing 210009, P. R. China.
authors: Weihua
authors: W
authors: Chu
authors: School of International Pharmaceutical Business, China Pharmaceutical University, Nanjing 210009, P. R. China.
authors: Shuxin
authors: S
authors: Zhou
authors: Department of Pharmaceutical Microbiology, China Pharmaceutical University, Nanjing 210009, P. R. China.
authors: Wei
authors: W
authors: Zhu
authors: Department of Pharmaceutical Microbiology, China Pharmaceutical University, Nanjing 210009, P. R. China.
authors: Xiyi
authors: X
authors: Zhuang
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D016980:Aeromonas hydrophila / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D000898:Antibiosis; D001407:Bacillus / Q000502:physiology*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D017077:Culture Media, Conditioned / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects; D054884:Host-Pathogen Interactions; D053038:Quorum Sensing / Q000502:physiology*; D012756:Sheep; D037521:Virulence Factors / Q000378:metabolism; D015027:Zebrafish / Q000382:microbiology*
chemical_list: D017077:Culture Media, Conditioned; D037521:Virulence Factors; C088386:homoserine lactone; D015107:4-Butyrolactone