Type 1 pili is the important virulence factors on the e . coli in fection in chicken . through the adhering of pili , e . coli adhered on the epidermic cell of aspiratory tract , which was the first step of invading in host 1型菌毛是鸡源致病性大肠杆菌的重要毒力因子，在致病过程中介导细菌吸附于鸡呼吸道粘膜上皮细胞完成入侵的第一步。