医院内感染是目前感染性疾病的主要问题之一。据美国疾病控制及预防中心估计每年约有 2 0 0～ 40 0万病人住院后发生医院感染 ,占住院病人的 5 %～ 1 0 %。这种医院内感染不仅可以导致病情的恶化 ,严重时还可致命 ,而近年来随着抗生素、肾上腺皮质激素、免疫抑制剂、肿瘤化疗药 Infection in the hospital is one of the main problems of infectious diseases. According to the US Centers for Disease Control and Prevention, an estimated 2 to 40 million patients are hospitalized after hospitalization each year, accounting for 5% to 10% of inpatients. This hospital infection can not only lead to the deterioration of the disease, can be fatal in severe cases, but in recent years with antibiotics, adrenocorticotropic hormone, immunosuppressive agents, cancer chemotherapy drugs