Treatment of Functional Bowel Disorders: Is There Room for Antibiotics?

Abstract

Small bowel bacterial overgrowth is a syndrome associated with a broad range of predisposing conditions, characterized by the presence of pathological amounts or types of bacteria at the level of the small bowel, clinically evident with a spectrum of symptoms such as diarrhea, flatulence, abdominal pain and bloating. Some of these symptoms are very common complaints in patients suffering from functional bowel disorders (FBDs). Although the pathophysiological mechanisms responsible for FBDs are certainly multifactorial and not yet completely understood, several pieces of evidence suggest that an increased metabolic activity of intestinal bacteria is responsible for gas-related intestinal symptoms in a large subgroup of patients. In addition, byproducts of colonic fermentation might be able to trigger symptoms in those patients displaying visceral hypersensitivity. Targeting enteric bacteria with antibiotics therefore represents a logical approach to FBDs. Although systemic antimicrobials have been mostly used in the past, the availability of poorly absorbed antibiotics like rifaximin, being safe and effective, has represented a step forward in the treatment of this challenging clinical condition.

Systematic review with meta‐analysis: rifaximin is effective and safe for the treatment of small intestine bacterial overgrowth

“…Several broad‐spectrum systemic antibiotics such as fluoroquinolones, metronidazole, tetracycline, amoxicillin‐clavulanic acid, chloramphenicol, etc., have been used to manage SIBO . However, they are usually associated with several and sometimes severe AEs …”

“…Several antibiotic regimens proved to be effective over the past 50 years, with treatment success ranging from 27% to 100% . Till the end of 90s, only systemic antimicrobials were used, whose adverse events (AEs) and detrimental effects on gut microbiota are today well known .…”

“…Rifaximin fulfils all the characteristics set by DuPont and Ericsson for the ideal antimicrobial that should be used for the treatment of gastrointestinal infections (including dysbiosis and SIBO). As a consequence, over the past decades, rifaximin has been largely used to treat SIBO even if there is currently a lack of a critical summary of evidence. To bridge this gap, a systematic review and meta‐analysis of randomised and nonrandomised studies was performed to evaluate the clinical effectiveness of and safety rifaximin to eradicate SIBO in adult patients.…”

Rifaximin intake leads to emergence of rifampin-resistant staphylococci

“…40 It has also been suggested that prophylactic rifaximin may offer a useful approach for preventing traveller's diarrhea, 41 that rifaximin for 7e10 days once a month may be useful in patients with symptomatic diverticulosis 42 and that it may represent an attractive alternative to prevent or limit NSAID-associated intestinal damage. 43 With respect to the results of our study showing rapid rifampin resistance after rifaximin intake, these broad and prophylactic indications may pose a problem in-hospital settings, especially in centres with prosthetic surgery.…”

Commentary: towards an effective and safe treatment of small intestine bacterial overgrowth

“…Different drugs (and different dosages) with a success rate ranging from 30% to 100% have been employed. 4 The systematic review and meta-analysis of Shah et al 5 represent a welcome and timely effort to provide clinicians with an evidence-based treatment of SIBO. The authors found that antibiotics are more effective than placebo (OR: 2.55; 95% CI: 1.29-5.04) in patients with symptoms attributable to SIBO.…”