An outbreak of E. coli O157:H7 hemorrhagic colitis associated with unpasteurized Gouda cheese

Capital Health-Public Health Division, Edmonton, Alberta.
Canadian journal of public health. Revue canadienne de santé publique (Impact Factor: 1.02). 05/2005; 96(3):182-4.
Source: PubMed


A cluster of E. coli O157:H7 hemorrhagic colitis was identified in metro Edmonton, Alberta through notifiable disease surveillance in late 2002.
Environmental health officers collected food histories and clinical information from cases in the cluster. The provincial public health laboratory conducted pulsed field gel electrophoresis (PFGE) analysis on E. coli O157:H7 isolates from cluster cases. Public health and food regulatory agencies conducted an investigation when a food source (unpasteurized gouda cheese) was implicated.
PFGE analysis revealed an "outbreak" profile in 13 cases. Onset dates for the outbreak cases ranged between October 2002 and February 2003. Two cases, aged 22 months and 4 years, developed hemolytic uremic syndrome as a result of their infection. Consumption of unpasteurized gouda cheese produced at a local dairy farm was reported by 12 of 13 outbreak cases in the 2 to 8 days prior to illness. E. coli O157:H7 was isolated from 2 of 26 cheese samples manufactured by the implicated producer. The cheese isolates had indistinguishable PFGE profiles as compared with outbreak case isolates. Implicated cheese was found to be contaminated with E. coli O157:H7 104 days after production, despite having met regulated microbiological and aging requirements.
To our knowledge, this is the first confirmed outbreak of E. coli O157:H7 infection in Canada associated with raw milk hard cheese. A review of federal legislation vis-à-vis raw milk hard cheese may be in order.

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    • "STEC is another important foodborne pathogens responsible for outbreaks which may result in hemorrhagic colitis (HC) and lethal hemolytic uremic syndrome (HUS) [13]. Although most outbreaks of HC and HUS have been attributed to serotype O157:H7, infections are also caused by other serotypes, such as O26:H11, O103:H2, O111:H8, and O145:H28 [8, 10]. Salmonella is another important organism which represents well-recognized foodborne bacterial pathogens. "
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    • "Since its identification as human pathogen in 1982, Escherichia coli O157:H7 has being a pathogen of major concern due to its ability to cause from relatively mild to fatal illnesses, including bloody diarrhea, hemorrhagic colitis, hemolytic uremic syndrome and thrombotic thrombocytopenic purpura (Ferens and Hovde, 2011). Since the gastrointestinal tract of ruminants, mainly cattle, is the natural reservoir of E. coli O157:H7 (Mainil and Daube, 2005), the consumption of raw milk and dairy products has been associated with several foodborne illnesses caused by this pathogen (CDCP, 2007, 2008; CDSC, 1998, 1999; Guh et al., 2010; Honish et al., 2005; Morgan et al., 1993; Proctor and Davis, 2000; Rangel et al., 2005; Upton and Coia, 1994; Watanabe et al., 1999). "
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    • "Ruminants seem to constitute a reservoir of E. coli O157 in nature (Rey et al., 2003; Oporto et al., 2008). Contaminated unpasteurized dairy products such as raw milk and raw-milk cheese have been incriminated in recent foodborne STEC outbreaks (Deschenes et al., 1996; Honish et al., 2005; CDC, 2007). Fermented dairy products manufactured using raw milk contaminated with E. coli O157:H7 can pose a threat to human health, as it has been shown that, if present in raw milk, the pathogen can survive during the manufacturing and ripening stages of selected fermented dairy products that do not undergo a sufficient heating step or are contaminated after the heat treatment. "
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