Investigation of anti-bacterial properties of some plant extracts on vibrio vulnificus strains

Vibrio vulnificus is a Gram-negative mesophilic bacterium that is halophilic and asporogenous. It belongs to the gamma Proteobacteria phylum and family Vibrionaceae. It lives in coastal and estuary environments, and between April and October, it reaches peak levels in the Gulf of Mexico. Various environmental conditions, such as temperature, salinity, and pH, influence the activation of virulence genes in Vibrio vulnificus bacteria. Some literature reports state that antibiotic resistance is increasing in Vibrio vulnificus. Curanderismo, a popular alternative medicine derived from Mexican culture, has been overlooked by scientific investigation and may be used in lieu of pharmacologic antimicrobial agents. This study looked at the antibacterial capabilities of 10 typical herbal treatments used to treat wounds and infections in south Texas. This study investigated the effects of active plant extracts on strains of Vibrio vulnificus by Kirby-Bauer disk diffusion susceptibility testing; and whether active plant extracts affected on quorum-sensing-regulated virulence traits which manifests as biofilm formation against strains of Vibrio vulnificus. Each plant’s ethanolic tinctures were made and applied on blank diffusion disks, which were then dehydrated and tested for susceptibility to four strains of Vibrio vulnificus bacteria using Kirby-Bauer disk diffusion susceptibility tests: VV27562 ATCC (type strain) and three strains isolated from the Coastal Bend region, VVARA0040407-40, BS0607- 5 and NB0507-7, were then analyzed in triplicate. In addition, cultures of the four strains were grown for 96 hours in minimal medium in vitro, then cultures were grown in the absence or presence of plant tinctures. Cultures were then stained with 0.4% crystal violet to determine biofilm formation. Among selected plants, six plant tinctures exerted significant antimicrobial effect against the four Vibrio vulnificus strains. Preliminary evidence suggested that there may be some effect of certain plant tinctures on biofilm formation. This project suggests a new alternative in Vibrio vulnificus treatment for potentially increasing antibiotic resistance against Vibrio vulnificus bacterial strains.