The YfcO fimbriae gene enhances adherence and colonization abilities of avian pathogenic Escherichia coli in vivo and in vitro.
Chaperone-usher (CU) fimbriae, which are adhesive surface organelles found in many Gram-negative bacteria, mediate tissue tropism through the interaction of fimbrial adhesins with specific receptors expressed on the host cell surface. A CU fimbrial gene yfcO, was identified in avian pathogenic E. coli (APEC) strain DE205B via gene functional analysis. In this study, yfcO was found in 13.41% (11/82) of E. coli strains, including phylogenetic groups A, B1, B2 and D, with the highest percentage in group B2. The expression of yfcO in biofilm forming bacteria was significantly higher (P < 0.05) than that in the planktonic bacteria. A yfcO deletion mutant was constructed, and adherence to DF-1 chicken embryo fibroblast cells was analyzed in vitro. Compared to the wild-type (WT), adherence of the mutant to DF-1 cells was significantly decreased (P < 0.01). The mutant bacterial loads in the heart, brain and liver were significantly lower (P < 0.05) than those of the WT strain. Resistance of the mutant to acidic (acetic, pH 4.0, 20 min) and high osmolarity (2.5 M NaCl, 1 h) stress conditions decreased by 51.28% (P < 0.001) and 80.34% (P < 0.01), respectively. These results suggest that yfcO contributes to APEC virulence through bacterial adherence to host tissues.
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Yaxin
Y
Li
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Haojin
H
Wang
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Jianluan
J
Ren
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Ling
L
Chen
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Xiangkai
X
Zhuge
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Lin
L
Hu
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Dezhi
D
Li
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: tangfang@njau.edu.cn.
Fang
F
Tang
Key Lab of Animal Bacteriology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Jianjun
J
Dai
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D000825:Animal Structures / Q000382:microbiology; D000818:Animals; D001422:Bacterial Adhesion; D058491:Bacterial Load; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D002460:Cell Line; D002645:Chickens; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000382:microbiology; D010861:Fimbriae, Bacterial / Q000502:physiology*; D017353:Gene Deletion; D005838:Genotype; D012965:Sodium Chloride / Q000378:metabolism; D014774:Virulence
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; C000616355:YfcO protein, E coli; D012965:Sodium Chloride
Adhesion; Avian pathogenic E. coli (APEC); Chaperone-usher fimbriae; Virulence; yfcO