Clinical Conditions Associated With Bacterial Overgrowth

Shah, Ayesha; Holtmann, Gerald

doi:10.1016/b978-0-323-54843-4.00006-4

Cited by 10 publications

(7 citation statements)

References 153 publications

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“…This could be potentially explained by the poor sensitivity and specificity of glucose breath test 47 . It is well recognised that false positive results can occur in conditions associated with rapid gastrointestinal transit, loss of small intestinal absorptive surface, altered gastrointestinal tract anatomy, which allows some glucose loads to escape the small bowel absorption and subsequently get fermented in the colon 15,48 …”

Section: Discussionmentioning

confidence: 99%

“…Currently available tests for SIBO have limitations and there is no universally accepted gold standard. Previously, cultures of jejunal aspirates with >10 5 colony forming units per millilitre (CFU/mL) of colonic‐type bacteria has been used to diagnose SIBO 15 . However, optimal cut‐off values for diagnosing SIBO remain debated 16 .…”

Section: Introductionmentioning

confidence: 99%

“…. In addition, there are several methodological problems, including use of different substrates and different doses of substrates, length of the test, sampling intervals and definition of a normal and abnormal breath test, 15 which questions the validity as diagnostic tests in clinical practice.…”

Section: Introductionmentioning

confidence: 99%

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Duodenal bacterial load as determined by quantitative polymerase chain reaction in asymptomatic controls, functional gastrointestinal disorders and inflammatory bowel disease

Shah

Talley

Koloski

et al. 2020

Aliment Pharmacol Ther

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Summary Background Small intestinal bacterial overgrowth may play a role in gastrointestinal and non‐gastrointestinal diseases. Aims To use quantitative polymerase chain reaction (qPCR) to determine and compare bacterial loads of duodenal biopsies in asymptomatic controls, and patients with functional gastrointestinal disorders (FGIDs) and inflammatory bowel disease (IBD) including ulcerative colitis (UC) and Crohn’s disease (CD). To define effects of gastric acid inhibition on bacterial load, explore links of bacterial load and gastrointestinal symptoms in response to a standardised nutrient challenge and compare bacterial load with glucose breath test results. Methods In 237 patients (63 controls, 84 FGID and 90 IBD), we collected mucosal samples under aseptic conditions during endoscopy extracted and total DNA. Bacterial load metric was calculated utilising qPCR measurements of the bacterial 16S rRNA gene, normalised to human beta‐actin expression. Standard glucose breath test and nutrient challenge test were performed. Results The duodenal microbial load was higher in patients with FGID (0.22 ± 0.03) than controls (0.07 ± 0.05; P = 0.007) and patients with UC (0.01 ± 0.05) or CD (0.02 ± 0.09), (P = 0.0001). While patients treated with proton pump inhibitors (PPI) had significantly higher bacterial loads than non‐users (P < 0.05), this did not explain differences between patient groups and controls. Bacterial load was significantly (r = 0.21, P < 0.016) associated with the symptom response to standardised nutrient challenge test. Methane, but not hydrogen values on glucose breath test were associated with bacterial load measured utilising qPCR. Conclusions Utilising qPCR, a diagnosis of FGID and treatment with PPI were independently associated with increased bacterial loads. Increased bacterial loads are associated with an augmented symptom response to a standardised nutrient challenge.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Duodenal bacterial load as determined by quantitative polymerase chain reaction in asymptomatic controls, functional gastrointestinal disorders and inflammatory bowel disease

Shah

Talley

Koloski

et al. 2020

Aliment Pharmacol Ther

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“…SIBO often presents with nonspecific and a wide spectrum of unexplained gastrointestinal symptoms, which are often indistinguishable from the primary condition predisposing to bacterial overgrowth [25]. SIBO typically presents with gastrointestinal symptoms including diarrhoea, fullness, bloating, flatulence, abdominal pain and discomfort, or weight loss [26].…”

Section: Clinical Presentations Of Small Intestinal Bacterial Overgro...mentioning

confidence: 99%

Unravelling the controversy with small intestinal bacterial overgrowth

Shah

Ghoshal

Holtmann

2023

Current Opinion in Gastroenterology

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Purpose of review The aim of this review is to summarize the current and emergent approaches to characterize the small intestinal microbiota and discuss the treatment options for management of small intestinal bacterial overgrowth (SIBO). Recent findings This review captures the growing body of evidence for the role of SIBO, a type of small intestinal dysbiosis in the pathophysiology various gastrointestinal and extraintestinal disorders. We have highlighted the drawbacks of the available methods for characterizing the small intestinal microbiota and focus on the new culture-independent techniques to diagnose SIBO. Although recurrence is common, targeted modulation of the gut microbiome as a therapeutic option for management of SIBO is associated with improvement in symptoms and quality of life. Summary As a first step to precisely characterize the potential link between SIBO and various disorders, we need to address the methodological limitations of the available traditional tests for diagnosing SIBO. There is an urgency to develop culture independent techniques that can be routinely used in clinical setting, that will enable characterization of the gastrointestinal microbiome and explore the response to antimicrobial therapy including the links between long-lasting symptom resolution and the microbiome.

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“…Furthermore, breath tests have several methodological problems including use of different substrates and doses of substrates, length of the test, sampling intervals, and definition of a normal and abnormal breath test, which may question their validity as diagnostic tests in clinical practice. 11 Thus, one of the main limitations in diagnosing SIBO is the lack of sensitive and specific diagnostic tests. 12 …”

Section: Introductionmentioning

confidence: 99%