Norwegian Sheep Are an Important Reservoir for Human-Pathogenic Escherichia coli O26:H11

Brandal, Lin Thorstensen; Sekse, Camilla; Lindstedt, Bjørn-Arne; Sunde, Marianne; Løbersli, Inger; Urdahl, Anne Margrete; Kapperud, Georg

doi:10.1128/aem.00186-12

Cited by 31 publications

(19 citation statements)

References 61 publications

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“…Although the withinherd prevalence was low, previous research reported that 90% of Australian sheep farms had animals testing positive for STEC (46). In Norway, however, the risk of human infection from sheep was much more significant since almost 50% of the sheep O26 isolates had multiple-locus variable number tandem repeat analysis profiles similar to that found in human clinical cases (35). The importance of sheep in STEC epidemiology was also demonstrated by Oporto et al (47), who reported that greater than 50% of sheep herds in Spain had animals shedding non-O157 STEC compared to 20.7% in dairy cattle and 46% in beef cattle.…”

Section: Small Ruminantsmentioning

confidence: 88%

“…Although cattle have been identified as the major reservoir for STEC in the United States, small ruminants play a greater role in the epidemiology of STEC infections in other countries. For example, sheep have been identified as the host of significance in Australia (1) and have also been recognized as an important reservoir of STEC O26 in Norway (35). In addition to STEC serogroups O157 and O26, sheep have been cited as reservoirs for more than 100 other serotypes of STEC, including O115, O128, and O130 (34,35) Transmission of STEC to small ruminants occurs through the same pathway as in cattle.…”

Section: Small Ruminantsmentioning

confidence: 99%

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Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

2014

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Shiga toxin-producing Escherichia coli (STEC) strains have been detected in a wide diversity of mammals, birds, fish, and several insects. Carriage by most animals is asymptomatic, thus allowing for dissemination of the bacterium in the environment without detection. Replication of the organism may occur in the gastrointestinal tract of some animals, notably ruminants. Carriage may also be passive or transient, without significant amplification of bacterial numbers while in the animal host. Animals may be classified as reservoir species, spillover hosts, or dead-end hosts. This classification is based on the animal's ability to (i) transmit STEC to other animal species and (ii) maintain STEC infection in the absence of continuous exposure. Animal reservoirs are able to maintain STEC infections in the absence of continuous STEC exposure and transmit infection to other species. Spillover hosts, although capable of transmitting STEC to other animals, are unable to maintain infection in the absence of repeated exposure. The large diversity of reservoir and spillover host species and the survival of the organism in environmental niches result in complex pathways of transmission that are difficult to interrupt.

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Section: Small Ruminantsmentioning

confidence: 88%

Section: Small Ruminantsmentioning

confidence: 99%

Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

2014

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“…Confirmation of stx 1 , stx 2 , and eae was done at the National Reference Laboratory for Enteropathogenic Bacteria (NRL) at the NIPH (24,25).…”

Section: Methodsmentioning

confidence: 99%

PCR-Based Detection and Molecular Characterization of Shiga Toxin-Producing Escherichia coli Strains in a Routine Microbiology Laboratory over 16 years

et al. 2014

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dShiga toxin-producing Escherichia coli (STEC) is a heterogeneous group of bacteria causing disease ranging from asymptomatic carriage and mild infection to hemolytic uremic syndrome (HUS). Here, we describe patients with STEC infection and characterize the STEC strains detected in our laboratory by use of PCR for stx 1 , stx 2 , and eae from 1996 through 2011. Patient information was collected from referral forms and from the Norwegian Surveillance System for Communicable Diseases. STEC isolates were characterized with respect to serogroup or serotype, selected potential virulence genes, and multilocus variable-number tandemrepeat analysis (MLVA) genotype. STEC strains were isolated from 138 (1.09%) of 12,651 patients tested. STEC strains of serogroups O26, O103, O121, O145, and O157 were the most frequent. These serogroups, except non-sorbitol-fermenting O157, were also the most frequent among the 11 patients (all <5 years old) who developed HUS. Twenty-four STEC strains were classified as being HUS associated based on an epidemiological link to a HUS case, including an MLVA genotype identical to that of the STEC strain. The age of the patient (<5 years) and the genes eae and stx 2a were significantly associated with HUS-associated STEC (P < 0.05 for each parameter), while stx 1 was associated with non-HUS-associated STEC (P < 0.05). All of the potential virulence genes analyzed, except ehxA, were significantly more frequent among HUS-associated than non-HUS-associated strains (P < 0.05 for each gene). However, these genes were also present in some non-HUS-associated STEC strains and could therefore not reliably differentiate between HUS-associated and non-HUS-associated STEC strains.

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“…The presence of naturally occurring VTEC has been widely reported in sheep, and studies indicate that sheep feces and sheep meat are important reservoirs of human pathogenic VTEC (49)(50)(51)(52)(53)(54)(55). Seasonal prevalence of VTEC in sheep has been reported (54,56), with incidences peaking in summer months in a similar trend to that in cattle and human infections (45).…”

Section: Carriage Of Vtec In Sheep and Goatsmentioning

confidence: 70%

Veterinary Public Health Approach to Managing Pathogenic Verocytotoxigenic Escherichia coli in the Agri-Food Chain

Duffy

McCabe

2014

Microbiol Spectr

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Verocytoxigenic Escherichia coli (VTEC) comprises many diverse serogroups, but seven serogroups, O157, O26, O103, O145, O111, O21, and O45, have been most commonly linked to severe human infections, though illness has also been reported from a range of other VTEC serogroups. This poses challenges in assessing the risk to humans from the diverse range of VTEC strains that may be recovered from animals, the environment, or food. For routine assessment of risk posed by VTEC recovered from the agri-food chain, the concept of seropathotype can be used to rank the human risk potential from a particular VTEC serogroup on the basis of both serotype (top seven serogroups) and the presence of particular virulence genes (vt in combination with eae, or aaiC plus aggR). But for other VTEC serogroups or virulence gene combinations, it is not currently possible to fully assess the risk posed. VTEC is shed in animal feces and can persist in the farm environment for extended periods ranging from several weeks to many months, posing an ongoing reservoir of contamination for grazing animals, water courses, and fresh produce and for people using farmland for recreational purposes. Appropriate handling and treatment of stored animal waste (slurries and manures) will reduce risk from VTEC in the farm environment. Foods of animal origin such as milk and dairy products and meat may be contaminated with VTEC during production and processing, and the pathogen may survive or grow during processing operations, highlighting the need for well-designed and validated Hazard Analysis Critical Control Point management systems. This article focuses on a veterinary public health approach to managing VTEC, highlighting the various routes in the agri-food chain for transmission of human pathogenic VTEC and general approaches to managing the risk.

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Norwegian Sheep Are an Important Reservoir for Human-Pathogenic Escherichia coli O26:H11

Abstract: ABSTRACTA previous national survey ofEscherichia coliin Norwegian sheep detectedeae-positive (eae+)E. coliO26:H11 isolates in 16.3% (80/491) of the flocks. The purpose of the present study was to evaluate the human-pathogenic potential of these ovine isolates by comp… Show more

Cited by 31 publications

References 61 publications

Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

PCR-Based Detection and Molecular Characterization of Shiga Toxin-Producing Escherichia coli Strains in a Routine Microbiology Laboratory over 16 years

Veterinary Public Health Approach to Managing Pathogenic Verocytotoxigenic Escherichia coli in the Agri-Food Chain

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