The flagella of F18ab Escherichia coli is a virulence factor that contributes to infection in a IPEC-J2 cell model in vitro.
Bacterial flagella contribute to pathogen virulence; however, the role of flagella in the pathogenesis of F18ab E. coli-mediated swine edema disease (ED) is not currently known. We therefore evaluated the role of flagella in F18ab E. coli adhesion, invasion, biofilm formation, and IL-8 production using an in vitro cell infection model approach with gene-deletion mutant and complemented bacterial strains. We demonstrated that the flagellin-deficient fliC mutant had a marked decrease in the ability to adhere to and invade porcine epithelial IPEC-J2 cells. Surprisingly, there was no difference in adhesion between the F18 fimbriae-deficient ΔfedA mutant and its parent strain. In addition, both the ΔfedA and double ΔfliCΔfedA mutants exhibited an increased ability to invade IPEC-J2 cells compared to the wild-type strain, although this may be due to increased expression of other adhesins following the loss of F18ab fimbriae and flagella. Compared to the wild-type strain, the ΔfliC mutant showed significantly reduced ability to form biofilm, whereas the ΔfedA mutant increased biofilm formation. Although ΔfliC, ΔfedA, and ΔfliCΔfedA mutants had a reduced ability to stimulate IL-8 production from infected Caco-2 cells, the ΔfliC mutant impaired this ability to a greater extent than the ΔfedA mutant. The results from this study clearly demonstrate that flagella are required for efficient F18ab E. coli adhesion, invasion, biofilm formation, and IL-8 production in vitro.
College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China.
Qiangde
Q
Duan
Mingxu
M
Zhou
Xiaofang
X
Zhu
Wenbin
W
Bao
Shenglong
S
Wu
Xiaosai
X
Ruan
Weiping
W
Zhang
Yang
Y
Yang
Jun
J
Zhu
Guoqiang
G
Zhu
D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology; D018938:Caco-2 Cells; D004488:Edema Disease of Swine / Q000382:microbiology*; D004847:Epithelial Cells / Q000166:cytology / Q000382:microbiology; D004926:Escherichia coli / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000378:metabolism / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000378:metabolism / Q000502:physiology*; D036781:Fimbriae Proteins / Q000378:metabolism / Q000502:physiology*; D010861:Fimbriae, Bacterial / Q000378:metabolism; D005407:Flagella / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D013552:Swine; D014774:Virulence; D037521:Virulence Factors / Q000378:metabolism / Q000502:physiology
D029968:Escherichia coli Proteins; C113053:FedA protein, E coli; D016209:Interleukin-8; D037521:Virulence Factors; D036781:Fimbriae Proteins