Article

The role of drinking water in the transmission of antimicrobial-resistant E. coli

Mount Sinai Hospital, Toronto, ON, Canada.
Epidemiology and Infection (Impact Factor: 2.54). 06/2011; 140(4):633-42. DOI: 10.1017/S0950268811001038
Source: PubMed

ABSTRACT

To determine whether drinking water contaminated with antimicrobial-resistant E. coli is associated with the carriage of resistant E. coli, selected households sending water samples to Ontario and Alberta laboratories in 2005-2006 were asked to participate in a cross-sectional study. Household members aged ≥12 years were asked to complete a questionnaire and to submit a rectal swab. In 878 individuals, 41% carried a resistant strain of E. coli and 28% carried a multidrug-resistant strain. The risk of carriage of resistant E. coli was 1·26 times higher for users of water contaminated with resistant E. coli. Other risk factors included international travel [prevalence ratio (PR) 1·33], having a child in nappies (PR 1·33), being male (PR 1·33), and frequent handling of raw red meats (PR 1·10). Protecting private water sources (e.g. by improving systems to test and treat them) may help slow the emergence of antimicrobial resistance in E. coli.

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    • "Another characteristic of E. coli that makes them a considerable threat is their ability to acquire MGEs, which can be transferred to other members of the enteric microbial community, including transient pathogens (Winokur et al., 2001). There are a few transmission routes by which humans are thought to be infected by ARB: person-to-person contact and the ingestion of contaminated food and drinking water have been implicated, with exposure possible within healthcare settings and in the wider community (Coleman et al., 2012; Kennedy and Collignon, 2010; Valverde et al., 2008). However, the natural environment has so far received little attention as a potentially significant setting in which people are exposed to ARB. "
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    ABSTRACT: Infections caused by antibiotic resistant bacteria (ARB) are associated with poor health outcomes and are recognised globally as a serious health problem. Much research has been conducted on the transmission of ARB to humans. Yet the role the natural environment plays in the spread of ARB and antibiotic resistance genes is not well understood. Antibiotic resistant bacteria have been detected in natural aquatic environments, and ingestion of seawater during water sports is one route by which many people could be directly exposed. The aim was to estimate the prevalence of resistance to one clinically important class of antibiotics (third-generation cephalosporins (3GCs)) amongst Escherichia coli in coastal surface waters in England and Wales. Prevalence data was used to quantify ingestion of 3GC-resistant E. coli (3GCREC) by people participating in water sports in designated coastal bathing waters. A further aim was to use this value to derive a population-level estimate of exposure to these bacteria during recreational use of coastal waters in 2012. The prevalence of 3GC-resistance amongst E. coli isolated from coastal surface waters was estimated using culture-based methods. This was combined with the density of E. coli reported in designated coastal bathing waters along with estimations of the volumes of water ingested during various water sports reported in the literature to calculate the mean number of 3GCREC ingested during different water sports. 0.12% of E. coli isolated from surface waters were resistant to 3GCs. This value was used to estimate that in England and Wales over 6.3 million water sport sessions occurred in 2012 that resulted in the ingestion of at least one 3GCREC. Despite the low prevalence of resistance to 3GCs amongst E. coli in surface waters, there is an identifiable human exposure risk for water users, which varies with the type of water sport undertaken. The relative importance of this exposure is likely to be greater in areas where a large proportion of the population enjoys water sports. Millions of water sport sessions occurred in 2012 that were likely to have resulted in people ingesting E. coli resistant to a single class of antibiotics (3GCs). However, this is expected to be a significant underestimate of recreational exposure to all ARB in seawater. This is the first study to use volumes of water ingested during different water sports to estimate human exposure to ARB. Further work needs to be done to elucidate the health implications and clinical relevance of exposure to ARB in both marine and fresh waters in order to fully understand the risk to public health.
    Full-text · Article · Mar 2015 · Environment International
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    • "Another characteristic of E. coli that makes them a considerable threat is their ability to acquire MGEs, which can be transferred to other members of the enteric microbial community, including transient pathogens (Winokur et al., 2001). There are a few transmission routes by which humans are thought to be infected by ARB: person-to-person contact and the ingestion of contaminated food and drinking water have been implicated, with exposure possible within healthcare settings and in the wider community (Coleman et al., 2012; Kennedy and Collignon, 2010; Valverde et al., 2008). However, the natural environment has so far received little attention as a potentially significant setting in which people are exposed to ARB. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Infections caused by antibiotic resistant bacteria (ARB) are associated with poor health outcomes and are recognised globally as a serious health problem. Much research has been conducted on the transmission of ARB to humans. Yet the role the natural environment plays in the spread of ARB and antibiotic resistance genes is not well understood. Antibiotic resistant bacteria have been detected in natural aquatic environments, and ingestion of seawater during water sports is one route by which many people could be directly exposed. The aim was to estimate the prevalence of resistance to one clinically important class of antibiotics (third-generation cephalosporins (3GCs)) amongst Escherichia coli in coastal surface waters in England and Wales. Prevalence data was used to quantify ingestion of 3GC-resistant E. coli (3GCREC) by people participating in water sports in designated coastal bathing waters. A further aim was to use this value to derive a population-level estimate of exposure to these bacteria during recreational use of coastal waters in 2012. The prevalence of 3GC-resistance amongst E. coli isolated from coastal surface waters was estimated using culture-based methods. This was combined with the density of E. coli reported in designated coastal bathing waters along with estimations of the volumes of water ingested during various water sports reported in the literature to calculate the mean number of 3GCREC ingested during different water sports. 0.12% of E. coli isolated from surface waters were resistant to 3GCs. This value was used to estimate that in England and Wales over 6.3 million water sport sessions occurred in 2012 that were likely to have resulted in the ingestion of at least one 3GCREC. Despite the low prevalence of resistance to 3GCs amongst E. coli in surface waters, there is an identifiable human exposure risk for water users, which varies with the type of water sport undertaken. The relative importance of this exposure is likely to be greater in areas where a large proportion of the population enjoys water sports. Millions of water sport sessions occurred in 2012 that were likely to have resulted in people ingesting E. coli resistant to a single class of antibiotics (3GCs). However, this is expected to be a significant underestimate of recreational exposure to all ARB in seawater. This is the first study to use volumes of water ingested using different water sports to estimate human exposure to ARB. Further work needs to be done to elucidate the health implications and clinical relevance of exposure to ARB in both marine and fresh waters in order to fully understand the risk to public health.
    Full-text · Article · Mar 2015
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    • "Recent epidemiological studies have included evaluation of ARB in drinking water and the susceptibility of commensal Escherichia coli in household members. For example, Coleman et al. (2012) reported that water, along with other factors not directly related to the local environment, accounted for the presence of resistant E. coli in humans. In many studies, native bacteria in drinking water systems have been shown to accumulate ARG (Vaz-Moreira et al. 2011). "
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    ABSTRACT: Only recently has the environment been clearly implicated in the risk of antibiotic resistance to clinical outcome, but to date there have been few documented approaches to formally assess these risks. We present possible approaches and identify research needs to enable human health risk assessments (HHRA) that focus on the role of the environment in antibiotic treatment failure caused by antibiotic-resistant pathogens. The authors participated in a workshop held in Quebec, Canada, March 4-8, 2012, to define the scope and objectives of how to undertake an environmental assessment of antibiotic resistance risks to human health. We focused on key elements of environmental resistance development 'hot-spots', exposure assessment (unrelated to food) and dose-response to characterize risks that may improve antibiotic resistance management options. Various novel aspects to traditional risk assessments were identified to enable an assessment of environmental antibiotic resistance. These include accounting for an added selective pressure on the environmental resistome that over time allows for antibiotic resistant bacterial (ARB) development; identifying and describing rates of horizontal gene transfer (HGT) in the relevant environmental 'hot-spot' compartments; and modifying traditional dose-response approaches to address doses of ARB for various health outcomes and pathways. In this paper we provide a proposal for the inclusion of environmental aspects of antibiotic resistance development in the processes of any HHRA addressing ARB. Due to limited available data a multi-criteria decision analysis (MCDA) approach is suggested as a useful way forward to undertake an HHRA of environmental antibiotic resistance that informs risk managers.
    Full-text · Article · Jul 2013 · Environmental Health Perspectives
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