Prevalence of Diarrhea-Associated Virulence Genes and Genetic Diversity in Escherichia coli Isolates from Fecal Material of Various Animal Hosts

Chandran, Abhirosh; Mazumder, Asit

doi:10.1128/aem.02653-13

Cited by 54 publications

(67 citation statements)

References 51 publications

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“…There are also no published case reports describing the clinical features of STEC infection in horses. The available published data on the prevalence of STEC in horses (85)(86)(87)(88) and donkeys (84,89,90) indicate that they are not major reservoirs of STEC and may instead be spillover hosts. Only one of 400 horse fecal samples screened in Germany was positive for STEC.…”

Section: Equinementioning

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: Equinementioning

confidence: 99%

“…They include llamas, moose, alpacas, antelopes, and yaks (79)(80)(81)(82)(83)(84). These animals can transmit STEC to humans directly by contact at petting zoos or indirectly through fecal deposition in water sources, vegetable fields, or recreational areas or on meat.…”

Section: Bison (Bison Bison)mentioning

confidence: 99%

Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

2014

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“…However, several diarrheagenic pathotypes, such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli, have been recognized (1) and implicated in many waterborne outbreaks (2,3,4). Several studies have shown that fecal material from various animals and humans contains E. coli carrying virulence genes associated with pathogenic E. coli (5,6,7,8) and can be a potential source of pathogenic E. coli in the surface waters. In recent years, various phenotypic and genotypic (library-dependent or library-independent) bacterial source tracking (BST) methods (9) have been developed to identify the source of fecal pollution in order to protect and manage source water quality and also to assess the potential public health risk associated with fecal contamination from a particular host source.…”

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confidence: 99%

“…Despite the large amount of data available on the occurrence of pathogenic E. coli in different animals (5)(6)(7)(8), only limited information on the prevalence of pathogenic E. coli in a wide range of avian host sources is available. For instance, the occurrence of STEC and EPEC has been previously found in some wild birds in Europe, Japan, and the United States, but these studies were limited to only gull and pigeon (15)(16)(17)(18)(19)(20)(21).…”

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confidence: 99%

Occurrence of Diarrheagenic Virulence Genes and Genetic Diversity in Escherichia coli Isolates from Fecal Material of Various Avian Hosts in British Columbia, Canada

Chandran

Mazumder

2014

Appl Environ Microbiol

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Contamination of surface water by fecal microorganisms originating from human and nonhuman sources is a public health concern. In the present study, Escherichia coli isolates (n ‫؍‬ 412) from the feces of various avian host sources were screened for various virulence genes: stx 1 and stx 2 (Shiga toxin-producing E. ). None of the isolates were found to be positive for stx 1 , while 23% (n ‫؍‬ 93) were positive for only stx 2 , representing STEC, and 15% (n ‫؍‬ 63) were positive for only eae, representing EPEC. In addition, five strains obtained from pheasant were positive for both stx 2 and eae and were confirmed as non-O157 by using an E. coli O157 rfb (rfb O157 ) TaqMan assay. Isolates positive for the virulence genes associated with ETEC and EIEC were not detected in any of the hosts. The repetitive element palindromic PCR (rep-PCR) fingerprint analysis identified 143 unique fingerprints, with an overall Shannon diversity index of 2.36. Multivariate analysis of variance (MANOVA) showed that the majority of the STEC and EPEC isolates were genotypically distinct from nonpathogenic E. coli and clustered independently. MANOVA analysis also revealed spatial variation among the E. coli isolates, since the majority of the isolates clustered according to the sampling locations. Although the presence of virulence genes alone cannot be used to determine the pathogenicity of strains, results from this study show that potentially pathogenic STEC and EPEC strains can be found in some of the avian hosts studied and may contaminate surface water and potentially impact human health.

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“…However, other animals, such as sheep, goats, swine, birds, wild animals, and humans, can also harbor STEC strains in their digestive tracts (35)(36)(37). For typical EPEC, the only reservoir is humans, whereas for atypical EPEC, both humans and other animals can be reservoirs (37).…”

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confidence: 99%

Molecular Profiling of Shiga Toxin-Producing Escherichia coli and Enteropathogenic E. coli Strains Isolated from French Coastal Environments

Balière

Rincé

Delannoy

et al. 2016

Appl Environ Microbiol

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Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) strains may be responsible for food-borne infections in humans. Twenty-eight STEC and 75 EPEC strains previously isolated from French shellfish-harvesting areas and their watersheds and belonging to 68 distinguishable serotypes were characterized in this study. High-throughput real-time PCR was used to search for the presence of 75 E. coli virulence-associated gene targets, and genes encoding Shiga toxin (stx) and intimin (eae) were subtyped using PCR tests and DNA sequencing, respectively. The results showed a high level of diversity between strains, with 17 unique virulence gene profiles for STEC and 56 for EPEC. Seven STEC and 15 EPEC strains were found to display a large number or a particular combination of genetic markers of virulence and the presence of stx and/or eae variants, suggesting their potential pathogenicity for humans. Among these, an O26:H11 stx 1a eae-␤1 strain was associated with a large number of virulence-associated genes (n ‫؍‬ 47), including genes carried on the locus of enterocyte effacement (LEE) or other pathogenicity islands, such as OI-122, OI-71, OI-43/48, OI-50, OI-57, and the high-pathogenicity island (HPI). One O91:H21 STEC strain containing 4 stx variants (stx 1a , stx 2a , stx 2c , and stx 2d ) was found to possess genes associated with pathogenicity islands OI-122, OI-43/48, and OI-15. Among EPEC strains harboring a large number of virulence genes (n, 34 to 50), eight belonged to serotype O26:H11, O103:H2, O103:H25, O145:H28, O157:H7, or O153:H2. IMPORTANCEThe species E. coli includes a wide variety of strains, some of which may be responsible for severe infections. This study, a molecular risk assessment study of E. coli strains isolated from the coastal environment, was conducted to evaluate the potential risk for shellfish consumers. This report describes the characterization of virulence gene profiles and stx/eae polymorphisms of E. coli isolates and clearly highlights the finding that the majority of strains isolated from coastal environment are potentially weakly pathogenic, while some are likely to be more pathogenic. E scherichia coli is a commensal aerobic bacterium of the warmblooded animal intestinal microbiota and is used as a fecal indicator in the environment to classify shellfish-harvesting and bathing areas (1). However, E. coli can become pathogenic through the acquisition of mobile genetic elements such as bacteriophages, pathogenicity islands, and plasmids. Among pathogenic E. coli strains are the Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) strains.STEC can cause infections ranging from uncomplicated diarrheas to hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS). Several STEC serotypes have been involved in numerous food-borne outbreaks worldwide (2, 3), and these strains have been identified as enterohemorrhagic E. coli (EHEC). Although E. coli O157:H7 has been the main serotype implicated in HC and HUS since the early ...

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Prevalence of Diarrhea-Associated Virulence Genes and Genetic Diversity in Escherichia coli Isolates from Fecal Material of Various Animal Hosts

Cited by 54 publications

References 51 publications

Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

Animal Reservoirs of Shiga Toxin-ProducingEscherichia coli

Occurrence of Diarrheagenic Virulence Genes and Genetic Diversity in Escherichia coli Isolates from Fecal Material of Various Avian Hosts in British Columbia, Canada

Molecular Profiling of Shiga Toxin-Producing Escherichia coli and Enteropathogenic E. coli Strains Isolated from French Coastal Environments

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