SIBO (Small Intestinal Bacterial Overgrowth) is a digestive disorder that is increasingly being diagnosed. In France, Coligenta, an antibiotic based on colistin and gentamicin, is often prescribed to treat it. However, rifaximin, another antibiotic, benefits from a far greater number of clinical studies and a more reassuring safety profile. Given this situation, it is crucial to question the relevance of the widespread use of Coligenta.
A single study for Coligenta
The efficacy of Coligenta in the treatment of SIBO is based primarily on a single open-label study of 60 patients (Bouchoucha et al., 2021). Although this study showed an improvement in symptoms in the majority of participants, its small size and the absence of a control group limit the scope of the conclusions.
In contrast, rifaximin has been the subject of numerous randomised controlled trials, demonstrating its efficacy and safety in the treatment of SIBO (Gatta & Scarpignato, 2017). A meta-analysis even confirmed that rifaximin is superior to placebo and other antibiotics in resolving symptoms and normalising breathing tests (Takakura et al., 2024).
Antibiotic resistance: a real danger
The widespread use of Coligenta also raises concerns about the development of antibiotic resistance. Colistin is an antibiotic of last resort for certain serious infections, and its excessive use in the treatment of SIBO could compromise its future efficacy. Gentamicin, although less critical, is a member of the aminoglycoside family of antibiotics and is also facing an increase in bacterial resistance (particularly in Gram-negative bacteria such as Escherichia Coli, Pseudomonas aeruginosa and Enterobacteriaceae).
Rifaximin, on the other hand, presents a low risk of antibiotic resistance because it acts locally in the intestine and is poorly absorbed by the body.
Frequent relapses
Studies show that relapses of SIBO are frequent, regardless of the antibiotic used (Lauritano et al., 2008). However, using antibiotics without tackling the underlying causes of SIBO merely masks the problem, which sooner or later returns (as I regularly observe in my consultations).
Treating the cause of SIBO
For long-term management of SIBO, it is essential to identify and treat the factors that encourage bacterial proliferation in the small intestine. These factors may include (but are not limited to):
- Impaired intestinal motility: Slow intestinal transit can lead to bacterial stagnation.
- Pancreatic insufficiency: Insufficient production of digestive enzymes can disrupt digestion and promote SIBO.
- Abnormal anatomy of the small intestine: Diverticula, adhesions or strictures can create areas of stagnation.
- Medication: Certain medications, such as proton pump inhibitors (PPIs), can alter the composition of the intestinal microbiota.
- Functional and metabolic disorders: adrenal fatigue, hypothyroidism, etc.
In conclusion, the choice between Coligenta and rifaximin for the treatment of SIBO must be an informed one, taking into account the scientific data available, the risks of antibiotic resistance and the importance of treating the cause of SIBO. It is crucial to favour a global approach that combines hygienic and dietary measures, management of the contributing factors and, if necessary, judicious antibiotic treatment.
In naturopathy and functional medicine, we use very effective natural antimicrobials (see, for example, my article on SIBO), but they won’t be effective if the causes are not tackled beforehand and in parallel. On the strength of this observation, which I’ve been making for more than 4 years as I’ve helped several hundred people with SIBO, I’ve created a training course for the general public that helps people understand the importance of working on the causes of SIBO and supporting and optimising the upper digestive system as much as possible before tackling the bacterial proliferation itself. You can find out more here: Sustainable Freedom from SIBO and Optimising the Digestive System Programme
References:
- Bouchoucha M, et al. (2021). COLIGENTA treatment of small intestinal bacterial overgrowth. Results of an open study. Dig Liver Dis, 53(1), 66-71.
- Gatta L, & Scarpignato C. (2017). Systematic review with meta-analysis: rifaximin is effective and safe for the treatment of small intestine bacterial overgrowth. Aliment Pharmacol Ther, 45(5), 604-16.
- Prevalence and risk factors for gentamicin resistance in Escherichia coli causing urinary tract infections” (Tadesse et al., 2012)
- “Aminoglycoside resistance: a continuing threat” (Shakil & Khan, 2011)
- Gentamicin resistance in bacteria isolated from patients with bloodstream infections in a tertiary care hospital” (Jahan et al., 2017)
- Theuretzbacher U, et al. (2015). Developing new antibiotics: challenges and opportunities. Nature Reviews Drug Discovery, 14(10), 727-737.
- Krause KM, et al. (2016). Antibiotic resistance: a global threat. International Journal of Antimicrobial Agents, 48(4), 357-366.
