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• Shengjiang Xiexin Decoction (SXD) effectively ameliorated AAD. • SXD recovered disordered gut microbiota in AAD rats. • SXD partly improved the integrity of intestinal barrier in AAD rats. • SXD recovered perturbed metabolic homeostasis in AAD rats. • Clear correlation among gut microbiota and metabolic profile was found. Antibiotic-associated diarrhea (AAD) has had a significant increase in the last years, with limited available effective therapies. Shengjiang Xiexin Decoction (SXD), a classic traditional Chinese medicine formula for treating diarrhea, is a promising alternative for reducing the incidence of AAD. This study aimed to explore the therapeutic effect of SXD on AAD and to investigate its potential therapeutic mechanism by integrated analysis of the gut microbiome and intestinal metabolic profile. 16S rRNA sequencing analysis of the gut microbiota and untargeted-metabolomics analysis of feces were performed. The mechanism was further explored by fecal microbiota transplantation (FMT). SXD could effectively ameliorate AAD symptoms and restore intestinal barrier function. In addition, SXD could significantly improve the diversity of the gut microbiota and accelerate the recovery of the gut microbiota. At the genus level, SXD significantly increased the relative abundance of Bacteroides spp (p < 0.01) and decreased the relative abundance of Escherichia_Shigela spp (p < 0.001). Untargeted metabolomics showed that SXD significantly improved gut microbiota and host metabolic function, particularly bile acid metabolism and amino acid metabolism. This study demonstrated that SXD could extensively modulate the gut microbiota and intestinal metabolic homeostasis to treat AAD. [Display omitted] [ABSTRACT FROM AUTHOR]

• The epidemiology of toxin genotypes and multi-locus sequence types of Clostridium difficile isolates in China was investigated. • A new tcdA -negative and tcdB -positive ST81 clone with high drug resistance is spreading in Beijing, China. Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhoea worldwide. In order to gain a better understanding about the molecular epidemiology of C. difficile in Beijing, China, molecular typing, antimicrobial susceptibility testing and drug resistance gene sequencing were performed on 174 strains of C. difficile collected from four large tertiary hospitals in Beijing. In total, 31 sequence types (STs) were identified among the 174 strains. ST81 was found to be the most prevalent (26.4%, 46/174), followed by ST2 (16.7%, 29/174) and ST54 (9.8%, 17/174). All isolates were susceptible to metronidazole and vancomycin. The test strains displayed resistance rates of 97.1%, 44.3% and 44.3% for ciprofloxacin, levofloxacin and moxifloxacin, respectively. ST81 isolates displayed a drug resistance rate of 97.8% for levofloxacin and moxifloxacin, which was significantly higher than ST2 (0%), ST54 (17.6%) and ST42 (0%) isolates (P <0.05). An amino acid mutation (T82I) was identified in GyrA, and the total mutation rate of the C. difficile strains was 40.8% (71/174). The mutation rate of ST81 isolates was 95.7% (44/46). Three amino acid mutations (D426N, S366A and D426V) were identified in GyrB, and the total mutation rate of GyrB was 39.1%. A double-site mutation in GyrB (S366A+D426V) was identified in all ST81 (n =46) isolates. In conclusion, the C. difficile ST81 clone showed a high level of resistance to fluoroquinolones in Beijing, highlighting the need for nationwide surveillance of CDI. [ABSTRACT FROM AUTHOR]