bacteroides fragilis

例句：

1. 1.The patient was diagnosed with a rare bacterial infection.
   患者被诊断出患有一种罕见的细菌感染。
2. 2.Bacteroides fragilis is a common commensal in the human gut.
   脆弱拟杆菌是人类肠道中常见的共生菌。
3. 3. Treatment of this condition often involves administering antibiotics to combat the bacteria.
   治疗这种状况通常需要给抗生素来对抗细菌。