[ODP22] 5. Pathogenicity -b. Toxins, effectors and physically active substances

[ODP-122] Detection of F4 Homologous Adhesion Factor in Escherichia coli Carrying astA

Yuki Suzuki¹, Yoshihiko Tanimoto^1,2, Yen Lin Chen¹, Hiromi Nakamura³, Kenji Ohya⁴, Yoshikazu Nishikawa⁵, Takayuki Wada¹ (¹Dept. Microbiol., Fac. Hum. Life. Sci., Osaka City Univ., ²Dept. Infect. Dis., Kobe Inst. Heal., ³Div. Microbiol., Osaka Inst. Publ. Heal., ⁴Div. Microbiol., Nat. Inst. Heal. Sci., ⁵Fac. Nutr. Food. Sci., Tezukayama Gakuin Univ.)

F4 (K88) adhesin of Escherichia coli is a virulence factor of porcine diarrhea and whereas is involved in adhesion to many hosts too. EAST1, encoded by astA, is known as a diarrheagenic toxin, but its pathogenicity is clearly unknown. In this study, we analyzed the prevalence of F4-homologous adhesins in EAST1-positive E. coli strains isolated from various sources.
The nucleotide sequences with high homology to faeE, encoding F4 (K88ac) chaperone, were searched by NCBI tblastx. Four regions with high identity were extracted and a real-time PCR detection system was constructed for them. The system was applied to 293 strains of astA-positive E. coli strains isolated from various samples. MiSeq (Illumina) was used to decipher the genome of the faeE-positive strains, and contigs of each strain were obtained.
Among all 293 strains, 121 (human: 8/16 (50.0%), bovine: 60/110 (54.5%), porcine: 20/101 (19.8%), and food: 33/66 (50.0%)) were positive for at least one region of the detection. Genome sequencing of faeE-positive strains from human verified that they possessed the F4-homologous adhesins, indicating the effectiveness of the system. It is verified that one of the strains possesses a toxin gene elt-2d, suggesting that this screening may be applicable to the detection of novel diarrheagenic E. coli.