Membrane Damage and Microbial Inactivation by Chlorine in the Absence and Presence of a Chlorine-Demanding Substrate

Abstract

The relationship between cell inactivation and membrane damage was studied in two gram-positive organisms, Listeria monocytogenes and Bacillus subtilis, and two gram-negative organisms, Yersinia enterocolitica and Escherichia coli, exposed to chlorine in the absence and presence of 150 ppm of organic matter (Trypticase soy broth). L. monocytogenes and B. subtilis were more resistant to chlorine in distilled water. The addition of small amounts of organic matter to the chlorination medium drastically increased the resistance of both types of microorganisms, but this effect was more marked in Y. enterocolitica and E. coli. In addition, the survival curves for these microorganisms in the presence of organic matter had a prolonged shoulder. Sublethal injury was not detected under most experimental conditions, and only gram-positive cells treated in distilled water showed a relevant degree of injury. The exposure of bacterial cells to chlorine in distilled water caused extensive permeabilization of the cytoplasmic membrane, but the concentrations required were much higher than those needed to inactivate cells. Therefore, there was no relationship between the occurrence of membrane permeabilization and cell death. The addition of organic matter to the treatment medium stabilized the cytoplasmic membrane against permeabilization in both the gram-positive and gram-negative bacteria investigated. Exposure of E. coli cells to the outer membrane-permeabilizing agent EDTA increased their sensitivity to chlorine and caused the shoulders in the survival curves to disappear. Based on these observations, we propose that bacterial envelopes could play a role in cell inactivation by modulating the access of chlorine to the key targets within the cell.

Exposure to chlorine affects the extracellular polymeric substance production and cell surface hydrophobicity in biofilm bacteria

“…The toxicity of chlorine to the biofilm and planktonic diatoms cells was reported by Nanchariah et al (2008). Membrane damage and microbial inactivation by chlorine in the presence and absence of a chlorine denaturing the substrate was also reported by Virto et al (2005). However, there is no information on the effect of chlorine on other factors, such as cell hydrophobicity, cell surface charge and EPS production that are involved in bacterial adhesion to surfaces.…”

“…Sodium hypochlorite is a nonspecific broad-spectrum oxidizing biocide and affects metabolic and physiological processes of microorganisms by causing damage to the cell membrane, proteins and nucleic acids (Phe et al 2004, Virto et al 2005, Nancharaiah et al 2008. It is highly effective against Gram-positive and Gramnegative bacteria.…”

Evaluation of the damage of cell wall and cell membrane for various extracellular polymeric substance extractions of activated sludge

“…Researchers have shown that some treatments (e.g. alkaline treatment, heating, chemical treatment and ultrasound) can damage microbial cell membranes (Goodford, 1971;Virto et al, 2005;Tachibana et al, 1999;Sampathkumar et al, 2003). For example, Sampathkumar et al (2003) found that high pH (>10.0) during trisodium phosphate treatment causes membrane damage of S. enterica.…”

Effect of Thermal and Radio Frequency Electric Fields Treatments on Escherichia coli bacteria in Apple Juice

“…To quantify the intracellular UV materials released from E. coli K-12, the extracts from treated and untreated cells containing the UV materials were measured at 260 and 280 nm with a Spectrophotometer (DUR 530, Beckman Coulter, Fullerton CA) according to published reports [29,30].…”