Fecal Microbiota in Patients with Irritable Bowel Syndrome Compared with Healthy Controls Using Real-Time Polymerase Chain Reaction: An Evidence of Dysbiosis Original paper
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Irritable Bowel Syndrome (IBS)
Irritable Bowel Syndrome (IBS)
Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder characterized by symptoms such as abdominal pain, bloating, and altered bowel habits. Recent research has focused on the gut microbiota's role in IBS, aiming to identify specific microbial signatures associated with the condition.
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Kimberly Eyer
Kimberly Eyer, a Registered Nurse with 30 years of nursing experience across diverse settings, including Home Health, ICU, Operating Room Nursing, and Research. Her roles have encompassed Operating Room Nurse, RN First Assistant, and Acting Director of a Same Day Surgery Center. Her specialty areas include Adult Cardiac Surgery, Congenital Cardiac Surgery, Vascular Surgery, and Neurosurgery.
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Karen Pendergrass
Location
India
Sample Site
Feces
Species
Homo sapiens
What was studied?
This study investigated fecal microbiota dysbiosis in patients with Irritable Bowel Syndrome (IBS) compared to healthy controls (HC) using quantitative real-time polymerase chain reaction (qPCR). The research aimed to identify specific microbial shifts that characterize different subtypes of IBS, including constipation-predominant (IBS-C), diarrhea-predominant (IBS-D), and unclassified IBS (IBS-U), highlighting the potential role of microbial imbalance in the pathophysiology of IBS.
Who was studied?
The study included 47 patients with IBS, diagnosed using the Rome III criteria, and 30 healthy controls. Among the IBS patients, 20 were classified as IBS-C, 20 as IBS-D, and 7 as IBS-U. Participants were recruited from a gastroenterology outpatient clinic in northern India. Exclusion criteria included recent use of antibiotics, probiotics, or prokinetics, as well as a history of gastrointestinal surgery, inflammatory bowel disease, or celiac disease.
What were the most important findings?
The study found significant microbial shifts in the fecal samples of IBS patients compared to healthy controls. Notably, the abundance of beneficial microbes like Bifidobacterium and Lactobacillus species was reduced, while pathogenic and opportunistic bacteria such as Pseudomonas aeruginosa, Bacteroides thetaiotamicron, Veillonella, Ruminococcus productus, and Gram-negative bacteria were significantly elevated in IBS patients. Among IBS subtypes, P. aeruginosa was found in 97.9% of IBS cases compared to only 33.3% of healthy controls, indicating its potential role as a microbial marker for IBS. Additionally, Bacteroides thetaiotamicron and segmented filamentous bacteria (SFB) were more abundant in IBS-D than in IBS-C, while Veillonella was elevated specifically in IBS-C patients. Abdominal distension and bloating were associated with increased numbers of Bacteroides thetaiotamicron, Clostridium coccoides, and P. aeruginosa, suggesting that microbial dysbiosis might contribute to symptom severity. Principal component analysis further confirmed distinct microbial profiles across IBS subtypes, supporting the hypothesis that gut microbiota composition is intrinsically linked to symptom manifestation in IBS.
| Parameter | Findings in IBS Patients |
|---|---|
| Microbial Diversity | Reduced abundance of Bifidobacterium and Lactobacillus species |
| Key Pathogenic Microbes | Elevated Pseudomonas aeruginosa, Bacteroides thetaiotamicron, Veillonella, Gram-negative bacteria |
| IBS Subtype Differences | Pseudomonas aeruginosa prevalent in 97.9% of IBS cases; Veillonella elevated in IBS-C, SFB in IBS-D |
| Symptom Associations | Abdominal distension and bloating correlated with Bacteroides thetaiotamicron, Clostridium coccoides, P. aeruginosa |
| Principal Component Analysis | Clear microbial separation between IBS subtypes and healthy controls |
| Diagnostic Implications | Pseudomonas aeruginosa and Bacteroides thetaiotamicron as potential biomarkers for IBS diagnosis |
What are the greatest implications of this study?
This study strongly supports the hypothesis that gut microbiota dysbiosis is associated with IBS and its subtypes. The pronounced presence of Pseudomonas aeruginosa and Bacteroides thetaiotamicron in IBS patients, especially those with diarrhea-predominant symptoms, suggests that these bacteria could serve as microbial biomarkers for IBS. Furthermore, the differential microbial patterns observed between IBS-C and IBS-D imply that targeted microbial therapies could be developed to address specific dysbiotic signatures. Importantly, the study highlights the role of gut dysbiosis in driving clinical symptoms such as bloating and abdominal distension, reinforcing the need for microbiome-targeted interventions as part of a comprehensive therapeutic strategy for IBS.
Irritable Bowel Syndrome (IBS)
Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder characterized by symptoms such as abdominal pain, bloating, and altered bowel habits. Recent research has focused on the gut microbiota's role in IBS, aiming to identify specific microbial signatures associated with the condition.