Basic clinical data
The antibiotics group included ten patients, as is shown in Table 1. The information of the non-antibiotic group (n=30) and the HCs group (n=35) have been shown in the previous study.[3] Significant differences were not found between the antibiotics and HCs groups in terms of age (8.6 ± 1.1 vs 7.2 ± 0.5 years, P = 0.2181) and sex ratio (50.0% vs 65.7% men, P = 0.366). In addition, significant differences were not found between the antibiotics and non-antibiotics groups in terms of age (8.6 ± 1.1 vs 8.3 ± 0.7 years, P = 0.8086), sex ratio (50.0% vs 46.7% men, P = 0.855), and duration of diseases (13.0 ± 19.0 vs 20.0 ± 25.6 years, P = 0.4318).
Alterations of gut microbial diversity in CCP
All CCP demonstrated a significantly reduced alpha diversity of the gut microbiota (P<0.01; Fig. 1A). An analysis of the beta diversity revealed that the abundance of genera (non-antibiotics group vs. HCs group; antibiotics group vs. HCs group) had distinct clustering (Fig. 1B and C). The gut microbiota's alpha diversity differences did not reveal statistical differences between the non-antibiotics and antibiotics groups (Fig. 1A). In addition, the analysis of beta diversity demonstrated that the abundance of genera had no distinct clustering between the non-antibiotics and antibiotics groups (Fig. 1B and C).
There were 15 altered genera with common abundance in the non-antibiotics and antibiotics groups compared to the HC group, including nine genera with decreased abundance (Faecalibacterium, Eubacterium, Subdoligranulum, Roseburia, Fusicatenibacter, Lachnospiraceae, Erysipelotrichaceae, Ruminiclostridium, and Parasutterella) (Fig. 2A–I) and six genera with increased abundance (Streptococcus, Enterococcus, Lactobacillus, Klebsiella, Actinomyces, and Rhodococcus) (Fig. 2J–O). Most (73.3%; 11/15) of the altered genera belonged to Firmicutes, 13.3% (2/15) to Actinobacteria, and 13.3% (2/15) to Proteobacteria (Supplementary Fig. 1A). Most (86.7%) of them were gram-positive strains, and 13.3% were gram-negative strains (Supplementary Fig. 1B). The area under receiver operating characteristics (AUROC) curve was used to analyze the top three probiotics whose abundance decreased greatly in CCP treated with antibiotics. The AUC of Faecalibacterium, Subdoligranulum, and Eubacterium was 0.87 (0.76–0.87, P<0.0001), 0.78 (0.65–0.78, P<0.01), and 0.81 (0.64–0.78, P<0.01), respectively. The AUC of the three genera after combining was 0.91 (0.82–0.91, P<0.001) (Fig. 3).
Only altered in the non-antibiotics group
There were 13 genera only altered in the non-antibiotics group, including ten genera with decreased abundance (Bifidobacterium, Collinsella, Phascolarctobacterium, Ruminococcaceae, Haemophilus, Butyricicoccus, Lachnospira, Flavonifractor, Actinobacillus, and Holdemania) and three genera with increased abundance (Propionibacterium, Alloprevotella, and Enterobacter) (Table 2). 46.2% (6/13) of the genera belonged to Firmicutes, 23.1% (3/13) to Actinobacteria, 23.1% (3/13) to Proteobacteria, and 7.7% (1/13) to Bacteroidetes (Supplementary Fig. 2A). Gram-positive bacteria accounted for 69.2%, whereas gram-negative bacteria accounted for 30.8% (Supplementary Fig. 2B). Among them, the top three genera Bifidobacterium, Collinsella, and Phascolarctobacterium with the greatest decreases in relative abundance were predicted as biomarkers for CCP not receiving antibiotics, and they were not appropriate as biomarkers for cases receiving antibiotics.
Only altered in the antibiotics group
In addition, there were 17 genera only altered in the antibiotics group, including five genera with decreased abundance (Anaerostipes, Coprococcus, Prevotellaceae, Ezakiella, and Slackia) and 12 genera with increased abundance (Cryptobacterium, Lysinimonas, Bradyrhizobium, Faecalibaculum, Allobaculum, Finegoldia, Ralstonia, Howardella, Peptostreptococcus, Granulicatella, Holdemanella, and Weissella) (Table 3). More than half (64.7%; 11/17) of them belonged to Firmicutes, 17.6% (3/17) to Actinobacteria, 11.8% (2/17) to Proteobacteria, and 5.9% (1/17) to Bacteroidetes (Supplementary Fig. 3A). Gram-positive bacteria accounted for 82.4%, whereas gram-negative bacteria accounted for 17.6% (Supplementary Fig. 3B). Compared to the 13 genera altered only in the non-antibiotics group, the differences of the genera and the proportion of gram-positive bacteria were not statistically significant (Firmicutes, 64.7% vs. 46.2%, P = 0.310; Actinobacteria, 17.6% vs. 23.1%, P = 1.000; Proteobacteria, 11.8% vs. 23.1%, P = 0.628; Bacteroidetes, 5.9% vs. 7.7%, P = 1.000; Gram-positive bacteria, 82.4% vs. 69.2%, P = 0.400).
Systematic analysis of gene function
Analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database indicated that the gut microbiota of the antibiotics group CCP was enriched in the phosphotransferase system and was depleted in the bacterial motility proteins and porphyrin and chlorophyll metabolism (Fig. 4).