Antibacterial properties of plant extracts from curanderismo (Mexican herbal medicine) on pathogenic strains of Vibrio Vulnificus isolated from the Coastal Bend region of Texas

Vibrio vulnificus, a Gram-negative mesophilic bacterium that belongs to the gamma Proteobacteria phylum and family Vibrionaceae, is halophilic and asporogenous and is autochthonous to marine and estuarine environments. Between April and October, the organism reaches peak levels in the Gulf of Mexico. Previous studies indicate that antibiotic resistance is increasing in Vibrio vulnificus. Finding a solution to this antibiotic resistance problem is critical for both aquaculture and medical care with persons exposed to Vibrio. One possible treatment modality to control the effects of antibiotic resistant bacteria is Curanderismo, a popular alternative plant-based medicine derived from Mexican culture, which has been overlooked by scientific investigation and may be used in lieu of pharmacologic antimicrobial agents. This study hypothesizes that certain plants may be used for treatment of antimicrobial-resistant strains (AMR) of Vibrio vulnificus. The objectives are to (1) investigate the effect of active plant extracts and tinctures on strains of Vibrio vulnificus by Kirby-Bauer disk diffusion susceptibility testing; (2) Investigate the effect of active plant extracts on the ability of Vibrio vulnificus to form biofilms, which indirectly observe quorum-sensing (QS)-regulated virulence traits. Ten typical herbal treatments of Curanderismo used to treat wounds and infections in south Texas were made as tinctures in against the four Vibrio vulnificus strains. In addition, biofilm assays revealed these six plant extracts showed better antimicrobial and anti-biofilm activity compared to the bacterial control. These findings demonstrate that certain plant tinctures may be plausible treatment methods and future studies will investigate specific plant tinctures on a wider range of south Texas Vibrio vulnificus strains.