Probiotics And Nosocomial Infection In Preterm Infants

Objective:We sought to assess whether early administration of prophylactic probiotics would provide a natural defense,thereby reducing the incidence and severity of the nosocomial infection in preterm neonates.We also evaluated its influence on the preterm immunity by seventh day.Methods:Accroding to the selecting criteria,44 preterm neonates whom admitted to the NICU in the PUMC hospital from May 2008 to March 2009 were randomized to either receiving a daily feeding supplementation with a probiotic mixture(Bifidobacteria infantis,Streptococcus thermophilus, and Lactobacillus) of 0.5×10~7colony forming units(CFU) twice per day in the fisrt two days after birth or to receive those supplements after seven days of birth.And evaluate the Severity of nosocomial infection between the two groups according to the diagnosis and frequency of nosocomial infection.Accroding to whether the baby was given probiotic mixture by seventh day,make them two groups,analyze T lymphocyte subgroup using flow cytometry,immunoglobin level,fecal pH,bacteria in throat and rectum in the first day and seventh day after birth to evaluate the mechanism of probiotics mixture preventing infection.Results:25 infants were early administrated with probiotics(in two days of birth) and 19 control infants administrated with probiotics after seven days of birth.The level of B cells percent was decreased in early administration group,which was increased in late administration group(P=0.039),and there was statistical significance.Percentage of CD4~+ T cells and T active cell were increased in both groups.(CD4~+T cell P=0.373, T active cell P=0.713).Percentage of NK cells were increased in two groups,which was much higher in early administration one(P=0.779). Percentage of cytotoxic T cells were both decreased,which was lower in late administration group(P=0.305).Percentage of CD8~+T cells were both decreased,which was much lower in late administration group(P=0.364). Percentage of suppressor T cells was decreased in early administration group,which was incresed in late administration group(P=0.717).Percentage of memory T cells were both decreased,which was much lower in late administration group(P=0.479).Ratios of CD4 to CD8 cells were both increased,which was much higher in late administration group(P=0.644) without statistical significance.There was no statistical difference in the IgA,IgM and IgG levels between the two groups.(P=0.144,P=0.316, P=0.554).The severity of nosocomial infection was much lower in the early administration group(P=0.008).Conclusion:Early probiotic supplementation have a trend to up-regulated of systemic immunity,and reduced both the incidence,severity of nosocomial infection.Further investigation was needed.