Chronic fatigue syndrome (CFS) is a chronic debilitating disease of unknown etiology associated with intestinal microecological dysregulation and disturbances in bacterial metabolism, and there are significant differences in the composition of the intestinal flora and intestinal permeability between patients with CFS and healthy populations, but the characteristics of the intestinal flora suggestive of CFS populations of different ages have rarely been reported.

To explore the characteristics of intestinal flora of CFS patients in different age groups, and to provide scientific basis for risk prevention and control of CFS in different age stages.

CFS patients from outpatient clinics of Sichuan Integrative Medicine Hospital between February 2021 and October 2021 were selected as the study subjects, and divided into three groups: 20 cases in the young group (18-34 years old), 20 cases in the middle-aged group (35-55 years old), and 20 cases in the old-aged group (56-80 years old). Basic information of the cases was collected, stool specimens were collected, and 16S rRNA high-throughput sequencing was used to detect the intestinal flora, and bioinformatics and statistical analysis were performed.

Differences in species composition and relative abundance were observed in CFS patients of different ages, with higher Pielou_e index of intestinal flora in the old-aged group, with statistically significant differences compared to the middle-aged group (P<0.05), and significant separation of the aggregated flora in the middle-aged group from the other two groups (P<0.01). Coprococcus, Megamonas, Dialister, and Acinetobacter were the core flora of the young group, and Ruminococcus was the core flora of the old group. The relative abundance of Pseudomonadales, Moraxellaceae, and Acinetobacter in the young group was higher than the middle-aged and old-aged groups (P<0.05). The relative abundance of Erysipelatoclostridium and Sellimonas in the middle-aged group was higher than the young and old-aged groups (P<0.05). The relative abundance of Eggerthellaceae and Bilophila in the old-aged group was higher than the young and the middle-aged group (P<0.05) .

There are differences in the diversity and composition of the intestinal flora of CFS patients in different age groups, and it was initially found that Acinetobacter and Erysipelatoclostridium can be used as the key flora to differentiate the intestinal flora of old-aged, middle-aged and young CFS patients.

慢性疲劳综合征（CFS）是一种病因不明的慢性衰弱性疾病，与肠道微生态失调和细菌代谢紊乱相关，CFS患者与健康人群肠道菌群组成和肠道通透性存在显著差异，但有关不同年龄CFS患者肠道菌群特征鲜见报道。

探究不同年龄组CFS患者肠道菌群的特征，为不同年龄组CFS风险防控提供科学依据。

选取2021年2—10月四川省中西医结合医院门诊CFS患者作为研究对象，分设3组：青年组（18~34岁）20例、中年组（35~55岁）20例和老年组（56~80岁）20例。收集病例基本信息，采集粪便标本，采用16S rRNA高通量测序方法检测肠道菌群，并对其进行生物信息学及统计分析。

不同年龄段CFS患者的物种组成和相对丰度存在差异，老年组肠道菌群Pielou_e指数高于中年组（P<0.05）；中年组聚集菌群与另外两组存在差异（P<0.01）。青年组核心菌属为粪球菌属（Coprococcus）、巨单胞菌属（Megamonas）、戴阿利斯特杆菌属（Dialister）、不动杆菌属（Acinetobacter），老年组核心菌属为瘤胃球菌属（Ruminococcus）。青年组假单胞菌目（Pseudomonadales）、莫拉菌科（Moraxellaceae）、不动杆菌属（Acinetobacter）的相对丰度高于中年组和老年组（P<0.05）；中年组丹毒丝梭菌属（Erysipelatoclostridium）、Sellimonas属的相对丰度高于青年组和老年组（P<0.05）；老年组埃格特菌科（Eggerthellaceae）、嗜胆菌属（Bilophila）相对丰度高于青年组和中年组（P<0.05）。

不同年龄组CFS患者肠道菌群多样性和组成存在差异，初步发现不动杆菌属和丹毒丝梭菌属可作为区别老年、中年及青年CFS患者肠道菌群的关键菌群。