Escherichia coli Contamination across Multiple Environmental Compartments (Soil, Hands, Drinking Water, and Handwashing Water) in Urban Harare: Correlations and Risk Factors

Abstract

<i>Escherichia coli</i> pathotypes (i.e., enteropathogenic and enterotoxigenic) have been identified among the pathogens most responsible for moderate-to-severe diarrhea in low- and middle-income countries (LMICs). Pathogenic <i>E. coli</i> are transmitted from infected human or animal feces to new susceptible hosts via environmental reservoirs such as hands, water, and soil. Commensal <i>E. coli</i>, which includes nonpathogenic <i>E. coli</i> strains, are widely used as fecal bacteria indicator, with their presence associated with increased likelihood of enteric pathogens and/or diarrheal disease. In this study, we investigated <i>E. coli</i> contamination in environmental reservoirs within households (<i>N</i> = 142) in high-population density communities of Harare, Zimbabwe. We further assessed the interconnectedness of the environmental compartments by investigating associations between, and household-level risk factors for, <i>E. coli</i> contamination. From the data we collected, the source and risk factors for <i>E. coli</i> contamination are not readily apparent. One notable exception is the presence of running tap water on the household plot, which is associated with significantly less <i>E. coli</i> contamination of drinking water, handwashing water, and hands after handwashing. In addition, <i>E. coli</i> levels on hands after washing are significantly associated with handwashing water contamination, hand contamination before washing, and diarrhea incidence. Finally, we observed that animal ownership increases <i>E. coli</i> contamination in soil, and <i>E. coli</i> in soil are correlated with contamination on hands before washing. This study highlights the complexity of <i>E. coli</i> contamination in household environments within LMICs. More, larger, studies are needed to better identify sources and exposure pathways of <i>E. coli</i>-and enteric pathogens generally-to identify effective interventions.