secondary infection

例句：

1. 1. The patient developed asecondary infection after the surgery.
   手术后，病人患上了继发性感染。
2. 2. The doctor advised against usingantibiotics for secondary infections.
   医生建议不要使用抗生素治疗继发性感染。
3. 3. The researchfound that secondary infections couldbe prevented by proper hand hygiene.
   研究发现，通过良好的手卫生可以预防继发性感染。