Adult Anti-Bacterial Agents Article Bacteria Bifidobacteriales Ciprofloxacin Clostridiales Combined Modality Therapy Fecal Microbiota Transplantation Feces Female Gastrointestinal Microbiome Humans Irritable Bowel Syndrome Lactobacillales Male Metronidazole Microbiome Middle Aged Quality of Life RNA 16S Rifaximin Severity of Illness Index Treatment Outcome adult antiinfective agent bacterium ciprofloxacin classification clinical article