随着近年来围产技术的进步,更多的小胎龄、极低出生体重的新生儿在出生后能得以存活。但同时因为这些特殊患者群具有机体各系统发育未成熟,尤其是免疫薄弱[1],以及皮肤和胃肠道黏膜屏障薄弱的这些内因,同时又具有需要长时间的住院治疗和救治过程中各种侵入性的检查操作、抗生素 With the improvement of perinatal technology in recent years, more newborns with very low gestational age and very low birth weight can survive after birth. At the same time, however, these particular patient groups have immaturity in their respective systems, especially immunocompromise [1], and these intrinsic causes of skin and gastrointestinal mucosal barrier weakness, as well as the need for long periods of hospitalization and treatment Intrusive inspection operations, antibiotics