PMID:23958403

Citation	Palaniyandi, S, Mitra, A, Herren, CD, Zhu, X and Mukhopadhyay, S (2013) LuxS contributes to virulence in avian pathogenic Escherichia coli O78:K80:H9. Vet. Microbiol. 166:567-75
Abstract	Avian pathogenic Escherichia coli (APEC) cause avian colibacillosis, a poultry disease characterized by multiple organ infections resulting in significant economic loss in the poultry industry. Several virulence factors are important for disease manifestation in APEC of which, role of quorum sensing has not been investigated. Quorum sensing is a population dependent cell-cell signaling system which modulates numerous physiological processes such as biofilm formation and virulence in multiple species. LuxS, a well-known controller in the QS, plays a role in regulating virulence in various bacterial species. Here we investigated the role of LuxS in regulating virulence in APEC O78:K80:H9. Mutation of luxS resulted in a significant reduction of virulence in APEC O78:K80:H9, evidenced by both in vivo and in vitro assays such as decreased invasion of internal organs in chicken embryo, reduced lethality in chicken embryo lethality assay, and altered lipopolysaccharide (LPS) profile. In addition, the abilities of the knockout strain to survive in chicken macrophage cell lines and to invade in chicken embryo fibroblast cells were significantly diminished. Further, structure and expression level of the LPS profile was significantly altered in the knockout strain, which may be one of the contributing factors for the persistence and virulence of APEC. Complementation of luxS gene in trans restored the virulence of the knockout strain to the level of wild-type bacteria. Taken together, these results show that LuxS contributes to the virulence in APEC O78:K80:H9 strain and partly explain the role played by LuxS in the pathogenesis of APEC strains.
Links	PubMed Online version:10.1016/j.vetmic.2013.07.009
Keywords	Animals; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Carbon-Sulfur Lyases/genetics; Carbon-Sulfur Lyases/metabolism; Chickens; Escherichia coli/genetics; Escherichia coli/metabolism; Escherichia coli/pathogenicity; Escherichia coli Infections/microbiology; Escherichia coli Infections/veterinary; Poultry Diseases/microbiology; Quorum Sensing; Virulence; Virulence Factors/genetics; Virulence Factors/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLX:A0A0K4BFT8		GO:0009405: pathogenesis	ECO:0000315:		P		Fig. 2. Avian Pathogenic Escherichia coli (STRAIN: 078: K80:H9) luxS (an S-ribosylhomocysteine lyase) mutant showed reduced chicken embryo lethality compared to wild-type and luxS/p-luxS carrying pSM8 inoculated in embryonated chicken eggs.	complete CACAO 12451

References

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