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Persistence of Bowl Water Contamination during Sequential Flushes of Contaminated Toilets.

Abstract

Toilets contaminated with infectious organisms are a recognized contact disease transmission hazard. Previous studies indicate that toilet bowl water can remain contaminated for several flushes after the contamination occurs. This study characterized contamination persistence over an extended series of flushes using both indicator particles and viable bacteria. For this study, toilets were seeded with microbe-size microbial surrogates and with Pseudomonas fluorescens or Clostridium difficile bacteria and flushed up to 24 times. Bowl water samples collected after seeding and after each flush indicated the clearance per flush and residual bowl water contaminant concentration. Toilets exhibited 3 + log10 contaminant reductions with the first flush, only 1-2 logs with the second flush, and less than 1 log thereafter. Contamination still was present 24 flushes post contamination. Clearance was modeled accurately by a two-stage exponential decay process. This study shows that toilet bowl water will remain contaminated many flushes after initial contamination, posing a risk of recurring environmental contamination and associated infection incidence.

Links

Authors+Show Affiliations

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Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, P.O. Box 26901, Oklahoma City, Oklahoma 72126-0901.

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Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, P.O. Box 26901, Oklahoma City, Oklahoma 72126-0901.

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Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, P.O. Box 26901, Oklahoma City, Oklahoma 72126-0901.

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Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, P.O. Box 26901, Oklahoma City, Oklahoma 72126-0901.

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Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Ministry of Health, Beijing 100021, PR China.

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Division of Applied Research and Technology, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio 45213.

Division of Applied Research and Technology, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio 45213.

Source

Journal of environmental health 80:3 2017 Oct pg 34-49

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29651169

Citation

TY - JOUR T1 - Persistence of Bowl Water Contamination during Sequential Flushes of Contaminated Toilets. AU - Johnson,David L, AU - Lynch,Robert A, AU - Villanella,Stephanie M, AU - Jones,Jacob F, AU - Fang,Haiqin, AU - Mead,Kenneth R, AU - Hirst,Deborah V L, PY - 2018/10/01/pmc-release PY - 2018/4/14/entrez PY - 2018/4/14/pubmed PY - 2018/4/14/medline KW - Clostridium difficile KW - aerosol KW - flush KW - infectious KW - plume KW - toilet KW - transmission SP - 34 EP - 49 JF - Journal of environmental health JO - J Environ Health VL - 80 IS - 3 N2 - Toilets contaminated with infectious organisms are a recognized contact disease transmission hazard. Previous studies indicate that toilet bowl water can remain contaminated for several flushes after the contamination occurs. This study characterized contamination persistence over an extended series of flushes using both indicator particles and viable bacteria. For this study, toilets were seeded with microbe-size microbial surrogates and with Pseudomonas fluorescens or Clostridium difficile bacteria and flushed up to 24 times. Bowl water samples collected after seeding and after each flush indicated the clearance per flush and residual bowl water contaminant concentration. Toilets exhibited 3 + log10 contaminant reductions with the first flush, only 1-2 logs with the second flush, and less than 1 log thereafter. Contamination still was present 24 flushes post contamination. Clearance was modeled accurately by a two-stage exponential decay process. This study shows that toilet bowl water will remain contaminated many flushes after initial contamination, posing a risk of recurring environmental contamination and associated infection incidence. SN - 0022-0892 UR - https://www.unboundmedicine.com/medline/citation/29651169/Persistence_of_Bowl_Water_Contamination_during_Sequential_Flushes_of_Contaminated_Toilets_ ER -