Prolonged CBD Exposure Is Associated with Higher Expression of flgA in Salmonella Typhimurium.

Ibrahim I.; Mathias A.; Johnson D.; Lawrence K.; Forte O.; Naidu N.; Huitt L.; Ajibola N.; Xu J.; Boakai R. et al. · Antibiotics (Basel, Switzerland) · 2026

**Background & Methods** This laboratory study examined the effects of prolonged cannabidiol (CBD) exposure on flgA gene expression and related phenotypic characteristics in Salmonella Typhimurium. Researchers compared a CBD-adapted bacterial strain with its parental susceptible strain, assessing flgA mRNA expression, motility, growth under varying pH conditions, nutrient starvation responses, and biofilm formation. **Key Findings** - The CBD-adapted Salmonella strain demonstrated approximately sixfold higher flgA mRNA expression and greater motility at neutral pH (7) compared to the parental strain. - pH-dependent responses were inconsistent: neither strain showed measurable migration at acidic pH (3), the adapted strain showed highly variable and limited migration at alkaline pH (12), and both strains exhibited reduced growth at extreme pH conditions. - Under nutrient starvation conditions, both strains experienced declining optical density (OD600), with the CBD-adapted strain declining more rapidly under several CBD conditions; biofilm formation varied by strain, CBD concentration, and incubation time. **Dosage & Administration** Specific CBD concentrations and exposure durations were not detailed in the abstract provided. The study involved prolonged exposure to CBD in laboratory conditions, but exact dosing parameters are not reported. **Safety & Adverse Effects** Not reported. This study focused on bacterial gene expression and phenotypic changes rather than toxicological or safety outcomes in mammalian systems. **Evidence Quality** This study has significant limitations. The authors explicitly acknowledge that findings are descriptive and correlational rather than causal—higher flgA expression was associated with CBD adaptation, but causation was not established. Critical methodological weaknesses include: (1) use of technical replicates rather than independent biological replicates, limiting statistical validity; (2) examination of only two bacterial strains, restricting generalizability; (3) inconsistent and variable results across conditions, particularly at extreme pH values. The study provides exploratory preliminary data suggesting the need for targeted genetic and phenotypic validation in future investigations. As a laboratory-based microbiological study published in 2026, this work does not directly address clinical outcomes or human health implications of CBD exposure.

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