Study of the Antibacterial Activity of Phenylacetic Acid Derivative Against the Causative Agent of Cholera

Abstract

The in vitro and in vivo activity of a phenylacetic acid derivative, diclofenac, was studied against V.cholerae O1 El Tor strains and biofilms formed by them. In the presence of a subinhibitory concentration of diclofenac (250 mg/l), a 4-fold decrease in the values of the minimum inhibitory concentrations of furazolidone and chloramphenicol was found in 30% and 100% of the strains resistant to these drugs, and a significant increase in the diameters of growth inhibition zones around discs with chloramphenicol. furazolidone, streptomycin (for all strains) and doxycycline (for two strains) in comparison with the control. Furazolidone, nalidixic acid, chloramphenicol, streptomycin, to which the infecting strain was resistant, were used in in vivo experiments in combination with diclofenac for the treatment of white mice; in the experimental group the number of surviving animals increased to 80% in comparison with monotherapy with these drugs (50% or less). The subinhibitory concentration of diclofenac did not have a pronounced effect on the antibiotic sensitivity of biofilms. The study using transmission electron microscopy method on the biofilm of the V.cholerae O1 El Tor 19667 strain after exposing it to diclofenac (250 mg/l) for 120 h revealed signs of destruction of the exopolysaccharide matrix. These results indicate the prospects for studying this group of drugs, as well as others in order to develop new ways to overcome bacterial resistance.