In vitro activity of water-soluble quaternary chitosan chloride salt against E-coli

The antibacterial effect of the N,N,N-trimethyl chitosan chloride salt (TMC) was evaluated against the bacterium Escherichia coli. The derivative was prepared via reaction of chitosan with dimethyl sulfate in the presence of NaOH and the Minimum Inhibitory Concentration was assessed by measuring the changes in turbidity and by counting of Colony Forming Units (c.f.u.). The results indicated good antibacterial activity against E. coli for all concentration of TMC tested (20.0; 7.5 and 3.5 mg/l) over 7 h of incubation. From the data, the ideal lethal concentration was determined as 20.0 mg/l.