Identification and inactivation of Gordonia, a new chlorine-resistant bacterium isolated from a drinking water distribution system

• Published in: Journal of water and health Vol. 18; no. 6; pp. 995 - 1008
• Main Authors: Lu, Nannan, Sun, Shaohua, Chu, Fumin, Wang, Mingquan, Zhao, Qinghua, Shi, Jinmiao, Jia, Ruibao
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.12.2020
• Subjects: Bacteria; Cell membranes; Cell morphology; Cell survival; Chlorine; Chlorine - pharmacology; Chlorine dioxide; Cytology; Deactivation; Deoxyribonucleic acid; Disinfectants - pharmacology; Disinfection & disinfectants; Distribution; DNA; Drinking Water; Flow cytometry; Gene amplification; Gordonia; Inactivation; Kinetics; Membrane permeability; Membranes; Microorganisms; Morphology; Permeability; Sodium; Sodium hypochlorite; Survival; Ultraviolet radiation; Ultraviolet Rays; Water conveyance; Water distribution; Water distribution systems; Water engineering; Water Purification; Water shortages; Water supply; Water treatment plants; United States > US; China; Yellow River
• ISSN: 1477-8920; 1996-7829
• DOI: 10.2166/wh.2020.143

Chlorine-resistant bacteria threaten drinking water safety in water distribution systems. In this study, a novel chlorine-resistant bacterium identified as Gordonia was isolated from the drinking water supply system of Jinan City for the first time. We examined the resistance and inactivation of the isolate by investigating cell survival, changes in cell morphology, and the permeability of cell membranes exposed to chlorine. After 240 min chlorine exposure, the chlorine residual was greater than 0.5 mg L and the final inactivation was about 3 log reduction, which showed that the Gordonia strain had high chlorine tolerance. Flow-cytometric analysis indicated that, following sodium hypochlorite treatments with increasing membrane permeability, culturable cells enter a viable but nonculturable state and then die. We also investigated the inactivation kinetics of Gordonia following chlorine dioxide and ultraviolet radiation treatment. We found that these treatments can effectively inactivate Gordonia, which suggests that they may be used for the regulation of chlorine-resistant microorganisms.