（四）幽门螺杆菌感染幽门螺杆菌是一种革兰阴性细菌，一般定植于胃的黏液层表面。
O O O B-dis I-dis I-dis I-dis I-dis I-dis I-dis B-mic I-mic I-mic I-mic I-mic O O O B-mic I-mic I-mic I-mic I-mic I-mic O O O O O O B-bod O B-bod I-bod I-bod O O O