Alternative Treatment to Remove Resistant Strains of <i>Vibrio cholerae</i> in Water

Abstract

Resistant strains of Vibrio cholerae have the potential to reemerge in aquatic reservoirs where they remain in a viable but not cultivable (VBNC) state, or as a rough variant embedded in an exopolysaccharide matrix, which could survive inadequate disinfection processes. This study investigated the chlorine (Cl2) and ozone (O3) inactivation kinetics for V. cholerae O1 El Tor, VBNC, and rough strains. The effect of both disinfectants was also evaluated at the cellular level using field emission scanning electron microscope (FESEM) micrographs. The Ct (C: concentration; t: contact time) values for Cl2 and O3 were established. Inactivation kinetics (log10 N0/N) confirmed that O3 is the better water treatment to inactivate VBNC and rough strains of V. cholerae. Compared with the smooth strain, resistant strains require a higher Ct of both Cl2 and O3 to inactivate the same percentage of cells. This study could contribute to preventing the spread of cholera through water consumption, mainly in endemic areas and developing countries, particularly when Ct values of smooth strains are applied in the disinfection of drinking water.