Small Intestinal Bacterial Overgrowth (SIBO) is gaining increasing recognition in gastroenterology, yet its diagnosis and management remain inconsistent across clinical settings. Despite its high prevalence in symptomatic patients, standard diagnostic thresholds (≥10³ vs. ≥10⁵ CFU/mL) and breath testing remain controversial.

This review aims to integrate current clinical and microbiome research to propose a novel microbiota-based framework for understanding and managing SIBO. Specifically, we highlight the Proteobacteria/Firmicutes ratio, particularly values >0.39, as a promising biomarker correlated with symptoms such as bloating and fecal urgency. This approach provides a unifying lens through which diagnostic variability may be reduced and microbial imbalance more precisely addressed. Additionally, we examine emerging evidence on the role of dietary patterns in reshaping the gut microbiota, proposing targeted nutritional interventions to reduce recurrence rates.

While this review draws from existing literature, it offers a novel synthesis that links microbial composition with diagnostic and therapeutic strategies. The recent introduction of ICD-10 code K82.11 further emphasizes the need for standardized frameworks in epidemiological tracking. Our findings support a shift from symptom-driven to microbiota-informed care models, with the potential to enhance clinical decision-making and long-term patient outcomes.