婴儿早期肠道双歧杆菌构建规律的初探

Colonization and development of intestinal bifidobacteria in early infancy

摘要:

目的 通过系统分析婴儿早期肠道双歧杆菌种群动态变化,初步探索婴儿肠道8 种双歧杆菌构建的规律。方法 收集2013 年3~4 月间16 例正常足月新生儿第1 次、第2、4、7、10、14、28、90 天的粪便,培养分离粪便中双歧杆菌;使用PCR 对分离菌株进行双歧杆菌属及其8 个种水平的鉴定。结果 从受试婴儿粪便中共检出优势双歧杆菌152 株,以B. breve 的检出率(22.4%)最高;第4 天开始在新生儿肠道检出双歧杆菌,定植率为8%;第7 天后双歧杆菌定植率迅速上升,至第28 天和3 月龄时定植率分别达到54% 和60%,均显著高于生后第4 天(均P<0.05)。第10 天时婴儿肠道已有成人型双歧杆菌B. catenulatum 定植,第14 天时检测到婴儿型双歧杆菌B. infantis 定植;至3 月龄时才在婴儿粪便中检测到高水平的婴儿型双歧杆菌B. infantis,且大部分婴儿肠道双歧杆菌种类总数不超过2 种。结论 本研究受试婴儿早期肠道双歧杆菌的多样性偏低,婴儿型双歧杆菌出现偏迟,相反成人型双歧杆菌发现较早。

Abstract:

Objective To study the characteristics of the colonization of 8 species of bifidobacteria by systematically profiling fecal bifidobacterial community in the early life of infants. Methods Fresh fecal samples including meconium samples were collected for culture and isolation of fecal bifidobacteria from 16 cases of full-term newborn infants born between March and April 2013 at their life of 2, 4, 7, 10, 14, 28, and 90 days. The isolated fecal bifidobacteria were taxonomically identified to genus and 8 species with PCR analysis. Results One hundred and fiftytwo predominant bifidobacteria strains were detected in the fecal samples, the detection rate of B. breve (22.4%) were the highest. Bifidobacteria were found in the feces of 8% infants 4 days after birth. The colonization rates increased to 54% and 60% at 28 days and 3 months respectively, significantly exceeding the colonization rate at 4 days after birth (P<0.05). Adult-type bifidobacteria B. catenulatum were found in the infants 10 days after birth, and infant-type bifidobacteria B. infantis were found at 14 days after birth, but infant-type bifidobacteria B. infantis were detected at a high level until 3 months after birth. The most tested infants had 2 species or less of bifidobacteria. Conclusions Intestinal bifidobacteria in infants might have less diversity in early infancy. Infant-type bifidobacteria appear late, while adult-type bifidobacteria colonize earlier.