Chlorine's Effect on E.Coli Proliferation

Rod-shaped Escherichia coli bacteria flourish in the intestinal tracts of vertebrates, including goats, cattle, chickens and humans. Native E. coli strains make up part of the normal gut bacteria in living organisms and are not pathogenic in their established environment; when these bacteria migrate to another species, or to another part of an organism's body, some strains become pathogens. Chlorination destroys E. coli in water and remains a primary means of ensuring municipal water quality.

Lysis

• Chlorine ions cause lysis, or cell death, to microbes in an aqueous solution. This highly reactive element first came into use as a disinfectant for the municipal water supply in Jersey City, New Jersey. Although it originally stopped the spread of a cholera epidemic, the additive also destroys E. coli bacteria. Chlorine dismantles cell membranes via oxidation, tearing apart delicate cells. In larger doses, chlorine damages multicellular organisms as well; tiny amounts suffice to stop E. coli proliferation.

Biofilm Disruption

• Chlorine in an aqueous solution disrupts bacterial colonies so severely that too few of the micro-organisms exist to form a protective biofilm. The slimy biofilm that colonies of bacteria, such as Escherichia coli produce acts as a self-contained environment, in which the microbes can move freely and further proliferate. Without a protective biofilm, individual E. coli bacteria face a harsher and more hostile environment. The same chlorine that prevents E. coli proliferation also disrupts other bacterial biofilm formation that could leave water with an unpleasant taste or texture.

Chlorine Gas

• Reactive chlorine makes such an effective disinfectant because of its reactive nature. Researchers have sought other ways to use the element as a way to keep water supplies pure, as consumers may find the taste of chlorinated water disagreeable. Chlorine dioxide gas bubbled through water has the same anti-microbial effect as liquid chlorine, according to a 1997 study at the Harbin University of Architecture and Engineering in Harbin, China. The oxidizing action of the chlorine remains the same in liquid or gaseous form; both forms effectively kill E. coli strains in water.

Chlorine Bleach

• Chlorine as a liquid or gas can stop E. coli proliferation in municipal water supplies; adding the toxic substance in minute amounts can do the same to soiled items, contaminated surfaces and standing water. Common household bleach contains chlorine. Adding a small amount of the liquid oxidizes E. coli and other potentially pathogenic bacteria in laundry loads and wash-water for contaminated counter-tops. Strong bleach also oxidizes pigment molecules, so add it only according to manufacturers' directions; bleach destroys dyes, as well as bacteria.