Influence of Exogenous Triiodothyronine (T3) on Fecal Shedding of Escherichia coli O157 in Cattle

Edrington, Tom S.; Callaway, Todd R.; Hallford, D. M.; Anderson, Robin C.; Nisbet, David J.

doi:10.1007/s00248-006-9159-0

Cited by 10 publications

(5 citation statements)

References 27 publications

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“…Our data indicated that hormones known to respond to day length (melatonin, tri-iodo-thryonine, thyroxine) were involved in the population dynamics and subsequent fecal shedding of E. coli O157:H7 in cattle [6, 7]. …”

Section: Resultsmentioning

confidence: 99%

Acyl-Homoserine-Lactone Autoinducer in the Gastrointesinal Tract of Feedlot Cattle and Correlation to Season, E. Coli O157:H7 Prevalence, and Diet

et al. 2008

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Acyl-homoserine-lactone autoinducer (AHL) produced by nonenterohemorrhagic Escherichia coli species in cattle appears to be required for enterohemorrhagic E. coli (EHEC) colonization of the gastrointestinal tract (GIT). The current research aimed to examine the effect of season, diet, EHEC shedding, and location within the GIT on AHL prevalence in the ruminant. Luminal content samples were collected from the rumen and rectum of feedlot cattle at slaughter in the spring, summer, fall, and winter for culture of E. coli O157:H7 and AHL determination. During the spring collection, samples were additionally collected from the cecum and small intestine, but these samples all were AHL negative and therefore not examined again. To assess the influence of diet on AHL prevalence, 14 lambs were fed either 100% forage or 80% concentrate diets and experimentally inoculated with EHEC. At 8 days after infection, all the lambs were killed, and necropsies were taken, with luminal contents collected from the GIT. The collections from the feedlot cattle had AHL in 100% of the rumen content samples from the spring, summer, and fall, but not in any of the winter samples. No other GIT samples from feedlot cattle were AHL positive, and all the samples from the sheep study were AHL negative. The cattle seemed to show a weak correlation between ruminal AHL and EHEC prevalence. This research found AHL only in the rumen and not in the lower GIT of feedlot cattle. However, it is unclear whether this is because the pH of the lower gut destroys the AHL or because a lack of certain bacteria in the lower gut producing AHL.

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Section: Resultsmentioning

confidence: 99%

Acyl-Homoserine-Lactone Autoinducer in the Gastrointesinal Tract of Feedlot Cattle and Correlation to Season, E. Coli O157:H7 Prevalence, and Diet

et al. 2008

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“…In evaluating which hormones (known to respond to changing da y-length) to examine, melatonin based on the secretion patterns that are inverse to E. co/i 0157:117 shedding patterns, stands out as a logical choice. However, a number of hormones offer intriguing possibilities, some of which we have demonstrated can also influence fecal shedding of E. colt 0157:1-17 (Edrington of al., 2007). The most probable scenario likely involves multiple hormones, or other compounds yet to he discovered, functioning in a cascade of events to influence i-:.…”

Section: Discussionmentioning

confidence: 99%

Influence of Exogenous Melatonin on Horizontal Transfer of Escherichia coli O157:H7 in Experimentally Infected Sheep

Edrington

Farrow²,

Genovese³

et al. 2009

Foodborne Pathogens and Disease

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The objective of the current research was to determine if exogenous melatonin would exert a "protective" effect on the gastrointestinal tract of sheep and prevent or reduce the horizontal transfer of Escherichia coli O157:H7 from experimentally infected to noninfected or "naïve" sheep. Sixteen cross-bred ewes were housed indoors and adapted to a high concentrate ration. Ewes were randomly assigned to one of four rooms and treatment (three ewes/room, six ewes/treatment) and received either control (gelatin capsule only) or melatonin (5.0 mg/kg body weight [BW]/d). Four additional ewes served as "carrier" sheep (one/room) and were experimentally infected via oral gavage with E. coli O157:H7. Three days post-challenge, carrier ewes were housed with naïve sheep and remained with them for the remainder of the experimental period. Treatments were administered to the naïve sheep 1 day prior to introduction of the carrier sheep and on each of the remaining 7 days of the experimental period. Fecal samples were collected via rectal palpation from the carrier sheep daily throughout experiment and from the naïve sheep daily for 5 days, starting 2 days following introduction of the carriers. On day 8 of the experiment, all ewes were euthanized and tissues from the rumen, ileum, cecum, colon, and rectum as well as their respective lumen contents collected. The carrier sheep quickly infected the naïve ewes, which had similar fecal concentrations as the carrier animals throughout the 5-day sampling period. Melatonin treatment had no effect (p > 0.10) on daily fecal shedding, luminal content concentrations, or in the percentage of gastrointestinal tract tissue positive for the inoculated strain of E. coli O157:H7.

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“…It is not known what climate-associated factors contribute to peak summer prevalence of EHEC; a hypothesis that day length impacts bovine hormones was tested by exposing cattle to additional 5 h of artificial lighting=day, and increased prevalence of EC O157:H7 was observed, compared to controls; 43 days after cessation of lighting, prevalence decreased to control levels (Edrington et al, 2006), and cattle treated with exogenous thyroid hormone shed the same numbers of EC O157 as controls in winter, and marginally less in summer (Edrington et al, 2007). Acyl-homoserine-lactone (AHL) autoinducer produced by non-EHEC appear to enhance EHEC colonization of the bovine GIT, and the rumen samples from feedlot cattle were negative for AHLs in the winter .…”

Section: Seasonal Prevalencementioning

confidence: 99%

Escherichia coliO157:H7: Animal Reservoir and Sources of Human Infection

Ferens

Hovde

2011

Foodborne Pathogens and Disease

479

327

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This review surveys the literature on carriage and transmission of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the context of virulence factors and sampling=culture technique. EHEC of the O157:H7 serotype are worldwide zoonotic pathogens responsible for the majority of severe cases of human EHEC disease. EHEC O157:H7 strains are carried primarily by healthy cattle and other ruminants, but most of the bovine strains are not transmitted to people, and do not exhibit virulence factors associated with human disease. Prevalence of EHEC O157:H7 is probably underestimated. Carriage of EHEC O157:H7 by individual animals is typically shortlived, but pen and farm prevalence of specific isolates may extend for months or years and some carriers, designated as supershedders, may harbor high intestinal numbers of the pathogen for extended periods. The prevalence of EHEC O157:H7 in cattle peaks in the summer and is higher in postweaned calves and heifers than in younger and older animals. Virulent strains of EHEC O157:H7 are rarely harbored by pigs or chickens, but are found in turkeys. The bacteria rarely occur in wildlife with the exception of deer and are only sporadically carried by domestic animals and synanthropic rodents and birds. EHEC O157:H7 occur in amphibian, fish, and invertebrate carriers, and can colonize plant surfaces and tissues via attachment mechanisms different from those mediating intestinal attachment. Strains of EHEC O157:H7 exhibit high genetic variability but typically a small number of genetic types predominate in groups of cattle and a farm environment. Transmission to people occurs primarily via ingestion of inadequately processed contaminated food or water and less frequently through contact with manure, animals, or infected people.

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Influence of Exogenous Triiodothyronine (T3) on Fecal Shedding of Escherichia coli O157 in Cattle

Cited by 10 publications

References 27 publications

Acyl-Homoserine-Lactone Autoinducer in the Gastrointesinal Tract of Feedlot Cattle and Correlation to Season, E. Coli O157:H7 Prevalence, and Diet

Acyl-Homoserine-Lactone Autoinducer in the Gastrointesinal Tract of Feedlot Cattle and Correlation to Season, E. Coli O157:H7 Prevalence, and Diet

Influence of Exogenous Melatonin on Horizontal Transfer of Escherichia coli O157:H7 in Experimentally Infected Sheep

Escherichia coliO157:H7: Animal Reservoir and Sources of Human Infection

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