Ecologically relevant effects of the insecticide cypermethrin at environmental concentrations on the bacteria isolated from 29/3 lake, Danang city
Abstract
Insecticides are often tested for toxicity but only for acute and lethal, not for chronic and sublethal effects on microbes. In this study, exposures of Escherichia coli and Pseudomonas sp. isolated from 29/3 lake in Danang city to the pesticide cypermethrin at environmentally relevant concentrations (0.25; 2.5 and 25 μg/L) were found to induce changes regarding ecological function such as enzymatic activities (cellulase and protease). While these sublethal concentrations of cypermethrin did not affect total vital bacteria cells of both bacteria species, they reduced activity of cellulase and protease enzymes in E. coli and Pseudomonas sp. With the application of cypermethrin at most of the concentrations, E. coli and Pseudomonas sp. had significant reduction in susceptibility to the antibiotics ceftazidim and ciprofloxacin. Specifically, exposure to 25μg/L of cypermethrin caused intermediate resistance to ciprofloxacin in E. coli.
Moraref