兒童疾病與腸道菌叢

Gut Microbiota and Pediatric Diseases

成人道中含有各種共生菌，每公克糞便約有1014細菌。胎兒存子宮內每天吞進的是無菌羊水，因此它的腸道是無菌的狀態。有趣的是剛出生嬰女如何獲得其菌叢？而其腸道菌又如何轉變成像大人一樣的型態？嬰幼兒腸道菌種、數量的演進與很多因素有關，例如生產方式、餵食方式、住院設置或母親健康狀況、種族、以及生活環境。傳統研究腸內菌是靠培養法，其敏感度有很大的變異性，完全決定於培養方式（如培養液的選擇）與環境因素。

It is interesting to know how the newborns and infants acquire and evolute gut microbiota. The origin of the bacteria colonizing the neonatal gastrointestinal tract is supposed to be affected by mode of delivery, feeding and maternal condition. To identify the individual bacteria, Temporal Temperature Gradient Gel Electrophoresis and clone-based sequencing of 16S rDNA amplicons replaced the conventional culture-based method to perform a more extensive exploration of the gut microbiota. The neonated may acquire phylum Proteobacteria initially, then rapidly followed by Actinobacteria, Bacteroidetes, and Firmicutes. These were the major bacteria patterns in infancy. The infants' gut microbiota pattern will gradually transit into the adult pattern at about the age of three, at what time the food intake of the children is similar to that of the adults. The current literature supports the idea that the gut microbiota signature acquired in infancy may predict or incline to the future development of diseases, for example, allergic diseases or metabolic diseases. Actually, people are more focusing on the functions of these gut microbiota. Although people in different geographic area may display different gut microbiota patterns, their gut microbiota may share the approximate functions. With the advent of next generation sequencing technology, a long-term prospective monitoring on the development of diseases and the evolution of gut microbiota will be very helpful to unravel their causal relationship. The gut microbiota may become the therapeutic target to manipulate.