[ODP22] 5. 病原性-b. 毒素・エフェクター・生理活性物質

[ODP-122] astA保有大腸菌におけるF4相同性接着因子の検出

鈴木 優希¹，谷本 佳彦^1,2，陳 彦霖¹，中村 寛海³，大屋 憲司⁴，西川 禎一⁵，和田 崇之¹ (¹大阪市立大・生活科学・微生物，²神戸市健康科学研究所，³大阪健康安全基盤研究所，⁴国立医薬品食品衛生研究所，⁵帝塚山学院大・人間科学)

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.