Effect of aqueous extract of Eucalyptus microcorys on Salmonella typhi strain adhered cells to polythene fragments in water microcosm

Abstract

This study was aimed at evaluating the effect of aqueous extract of Eucalyptus microcorys on the bacterial cells of Salmonella typhi adhered to polythene fragment at different cell growth phases in aquatic microcosm. The cell growth phases that have been considered are the lag, exponential, stationary and decline phases. The analyzes were performed in static conditions. The duration of cell adhesion process (DCAP) used to allow cell adhesion to polythene were 3h, 6h, 9h, and 24h. Polythene fragments containing adhered bacteria of known amount were then introduced into the solution containing different extract concentrations of Eucalyptus microcorys (10,15 and 20 g.l −1). Fragments were removed after 1h, 2 h and 3h contact time with extract solution. The results revealed that the extract of Eucalyptus microcorys causes the detachment of several bacterial cells initially adhered to fragments of polythene. The degree of detachment is modulated by the phase of cell growth. The largest reduction of Salmonella typhi cells adhered to polythene was observed with cells coming from exponential and stationary growth phases and also after 3h exposure to fragments in the extract.