Small Intestinal Bacterial Overgrowth in Patients with Refractory Functional Gastrointestinal Disorders

Abstract

Background/AimsSmall intestinal bacterial overgrowth (SIBO) is considered to be involved in the pathogenesis of functional gastrointestinal disorders (FGID). However, the prevalence and clinical conditions of SIBO in patients with FGID remain to be fully elucidated. Here, we examined the frequency of SIBO in patients with refractory FGID. MethodsWe prospectively enrolled patients with refractory FGID based on Rome III criteria. A glucose hydrogen breath test (GHBT) was performed using a gas analyzer after an overnight fast, with breath hydrogen concentration measured at baseline and every 15 minutes after administration of glucose for a total of 3 hours. A peak hydrogen value ≥ 10 ppm above the basal value between 60 and 120 minutes after administration of glucose was diagnosed as SIBO. ResultsA total of 38 FGID patients, including 11 with functional dyspepsia (FD), 10 with irritable bowel syndrome (IBS), and 17 with overlapping with FD and IBS, were enrolled. Of those, 2 (5.3%) were diagnosed with SIBO (one patient diagnosed with FD; the other with overlapping FD and IBS). Their symptoms were clearly improved and breath hydrogen levels decreased to normal following levofloxacin administration for 7 days. ConclusionsTwo patients initially diagnosed with FD and IBS were also diagnosed with SIBO as assessed by GHBT. Although the frequency of SIBO is low among patients with FGID, it may be important to be aware of SIBO as differential diagnosis when examining patients with refractory gastrointestinal symptoms, especially bloating, as a part of routine clinical care. (J Neurogastroenterol Motil 2016;22:60-68)

Prevalence of Small Intestine Bacterial Overgrowth in Patients With Gastrointestinal Symptoms

“…Our results show that approximately 20% of patients identified with SIBO only got their SIBO diagnosis by methane identification in the exhaled gas, which is consistent with the results found in the literature (6,16,20) . Thus, it is essential that the breath tests to diagnose SIBO be performed on devices capable of identifying the exhaled H 2 and CH 4 , in order to increase sensitivity and diagnostic accuracy.…”

“…The presence of overgrowth, as detected by the exhaled H 2 test has been described in 0-12.5% in the asymptomatic (20) volunteer group. However, it is important to note that the actual prevalence of the syndrome is not well known due to remaining difficulties for its diagnosis in daily practice (2) .…”

“…For this reason, there has been a recommendation to perform the test in modern equipment capable of detecting, concomitantly, the concentration of exhaled H 2 and methane (CH 4 ), making it more sensitive and more acurate (5,15,21) . Most studies point out that the diagnostic accuracy of the breath test using glucose is higher compared to that using lactulose (20) .…”

Functional dyspepsia

“…There is contradictory evidence on the role in functional dyspepsia of small-intestinal bacterial overgrowth, a condition in which the bacterial population in the small intestine is greater than the physiological state and composed of species that are typical of the colon microbiota 98,99 . One study has linked the composition of the faecal microbiota to abdominal pain, and enterotypes (that is, types of gut microbiota populations) in which bacteria of the Prevotella genus were predominant corre lated with less-intense pain 100 .…”

Serial Frozen Fecal Microbiota Transplantation in the Treatment of Chronic Intestinal Pseudo-obstruction: A Preliminary Study

“…5 SIBO may also in turn exacerbate intestinal dysmotility. 6,7 Currently, non-absorbable antibiotics (eg, rifaximin) are used to alleviate SIBO-associated symptoms. 8,9 This beneficial effect of antibiotics may in part be due altered location or quality of the patient's gastrointestinal microbiota.…”