Exploring microalgal lipids as anti-virulence agents targeting MDR Vibrio cholerae infection: A Step Toward Developing Herbal Oral Rehydration Salt (ORS) Formulations

Abstract

Introduction:Cholera, a life-threatening diarrheal disease caused by Vibrio cholerae, remains a major global health issue, especially in tropical regions. Increasing antibiotic resistance in V. cholerae strains poses a significant threat to effective treatment. Novel antivirulence strategies that do not promote resistance are urgently needed. Objectives: This study investigates the potential of lipid extracts and crude biomass derived from Chlorella variabilis (CV) and Chlorococcum sp. (CCM) microalgae to inhibit cholera toxin (CT) production by a multidrug-resistant V. cholerae strain (SRK-19), without affecting bacterial viability. Materials and Methods: Lipid extracts and crude freeze-dried biomass from CV and CCM were tested against V. cholerae SRK-19 in vitro for their effects on CT production (measured via ELISA) and bacterial viability. For in vivo validation, a rabbit ileal loop assay was performed, and fluid accumulation (FA ratio), colony-forming units (CFU), and CT levels were measured. Results: Both lipid extracts and crude biomass significantly reduced CT production in vitro in a dose-dependent manner, with up to 97.9% inhibition observed using CCM lipid extract at 150 μg/ml. Crude extracts achieved comparable inhibition, with CV and CCM biomass reducing CT levels by 93% and 97%, respectively, at 1 mg/ml. In vivo studies confirmed reduced FA ratios and CT levels in treated ileal loops, without affecting bacterial growth (CFU counts remained unchanged), indicating that bacterial viability was not compromised. Conclusion: Crude and lipid extracts from CV and CCM demonstrate potent antivirulence activity against V. cholerae by inhibiting CT production without promoting antimicrobial resistance. These findings support the development of a microalgae-based oral rehydration formulation as a promising alternative to conventional antibiotic therapy for cholera