Investigation of Small Intestinal Fungal Overgrowth (SIFO) and/or Small Intestinal Bacterial Overgrowth (SIBO) in Chronic, Unexplained Gastrointestinal Symptoms
Carolyn Jacobs, Jessica Valestin, Ashok Attaluri, Gideon K. Zamba, Satish S. Rao
Introduction: Unexplained gastrointestinal symptoms are common and many of these patients are labeled as having a functional gastrointestinal disorder. Without clear etiology, patients undergo repeated tests that pose a large health care burden and affect their quality of life. Although SIBO is well recognized, whether SIFO or mixed infection with SIBO contributes to persistent gastrointestinal symptoms is unknown. Aim: To investigate presence of SIFO or SIBO in this patient population. Methods: Patients with chronic gastrointestinal complaints and negative GI evaluations (endoscopy, blood tests, CAT scan) and no prior gastric or small intestinal surgery were evaluated. All patients underwent distal duodenal aspirate and culture for aerobic, anerobic and fungal organisms using aseptic technique using a Liguory nasobiliary catheter. Identification of fungal organisms in culture was consid- ered positive for SIFO;bacterial concentrations ≥10 3 cfu/mL was defined as positive for SIBO and presence of both as mixed SIFO/SIBO. Symptoms were recorded on validated scale and its severity scored on a Likert scale (0-3). Results: 124 (M/F=38/86; ages 17-82) subjects were evaluated; 77/124 (62%) had a positive culture for overgrowth. Among these, 23/124 (19%) had SIFO, 23/124 (19%) had mixed SIFO/SIBO and 31/124 (25%) had SIBO. All patients with SIFO grew candida. 36 subjects with SIBO had aerobic flora (enterococcus sp, streptococcus sp, etc), and 3 had anaerobic flora (bacteroides sp). Prevalence of symptoms and its severity are detailed in table. Nausea was more prevalent and severe in SIFO whereas abdominal pain and gas were more common in SIBO. Symptoms do not predict presence/ absence of infection. Conclusion: SIFO and mixed SIFO/SIBO overgrowth is common and occurs in three of five individuals with chronic, persistent GI symptoms in tertiary care practice. Duodenal aspirate/culture can facilitate diagnosis. Our findings reveal that SIFO, either alone or together with SIBO, may be one more important and hitherto unrecognized piece of the puzzle that could explain chronic refractory gastrointestinal symptoms.