scholarly journals Escherichia coli O157[ratio ]H7 infection of calves: infectious dose and direct contact transmission

2001 ◽  
Vol 127 (3) ◽  
pp. 555-560 ◽  
Author(s):  
T. E. BESSER ◽  
B. L. RICHARDS ◽  
D. H. RICE ◽  
D. D. HANCOCK
Keyword(s):  
Escherichia Coli ◽  
Direct Contact ◽  
Reservoir Host ◽  
Human Infection ◽  
Escherichia Coli O157 ◽  
Faecal Excretion ◽  
Infectious Dose ◽  
E Coli ◽  
Electrophoretic Patterns ◽  
Contact Transmission

Cattle are considered to be a reservoir host of Escherichia coli O157[ratio ]H7 and contaminated foods of bovine origin are important vehicles of human infection. In this study, the susceptibility of calves to experimental E. coli O157[ratio ]H7 infection following low oral exposures was determined. Two of 17 calves exposed to very low (<300 c.f.u.) doses, and 3 of 4 calves exposed to low (<10000 c.f.u.) doses, subsequently excreted the challenge strains in their faeces. All calves (n = 12) sharing isolation rooms with calves that excreted the challenge strain in their faeces similarly began faecal excretion of the same strains within 21 days or less. The identity between the challenge strains and the strains excreted in calf faeces was confirmed by restriction digestion electrophoretic patterns using pulsed field gel electrophoresis. Calves shed E. coli O157[ratio ]H7 in their faeces after very low dose exposures at concentrations ranging from <30 to >107 c.f.u./g, and for durations similar to the values previously reported for calves challenged by larger doses. The susceptibility of calves to infection following very low exposures or direct contact with infected calves has important implications for programmes for pre-harvest control of this agent.

scholarly journals Transmission and Infectious Dose of Escherichia coli O157:H7 in Swine

2004 ◽  
Vol 70 (9) ◽  
pp. 5331-5335 ◽  
Author(s):  
N. A. Cornick ◽  
A. F. Helgerson
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Management Practices ◽  
Reservoir Host ◽  
Escherichia Coli O157 ◽  
Infectious Dose ◽  
Fecal Shedding ◽  
E Coli ◽  
Naturally Occurring ◽  
Infected Donor

ABSTRACT Escherichia coli O157:H7 is only occasionally isolated from healthy swine, but some experimentally infected animals will shed the organism in their feces for at least 2 months. Potential explanations for the paucity of naturally occurring infections in swine, as compared to cattle, include a lack of animal-to-animal transmission so that the organism cannot be maintained within a herd, a high infectious dose, or herd management practices that prevent the maintenance of the organism in the gastrointestinal tract. We hypothesized that donor pigs infected with E. coli O157:H7 would transmit the organism to naïve pigs. We also determined the infectious dose and whether housing pigs individually on grated floors would decrease the magnitude or duration of fecal shedding. Infected donor pigs shedding <104 CFU of E. coli O157:H7 per g transmitted the organism to 6 of 12 naïve pigs exposed to them. The infectious dose of E. coli O157:H7 for 3-month-old pigs was approximately 6 × 103 CFU. There was no difference in the magnitude and duration of fecal shedding by pigs housed individually on grates compared to those housed two per pen on cement floors. These results suggest that swine do not have an innate resistance to colonization by E. coli O157:H7 and that they could serve as a reservoir host under suitable conditions.

scholarly journals Comparison between human and animal isolates of Shiga toxin-producing Escherichia coli O157 from Australia

2002 ◽  
Vol 128 (3) ◽  
pp. 357-362 ◽  
Author(s):  
N. FEGAN ◽  
P. DESMARCHELIER
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Infection ◽  
Pulsed Field Gel Electrophoresis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Animal Population ◽  
E Coli ◽  
Virulence Markers ◽  
Animal Isolates

There is very little human disease associated with enterohaemorrhagic Escherichia coli O157 in Australia even though these organisms are present in the animal population. A group of Australian isolates of E. coli O157:H7 and O157:H- from human and animal sources were tested for the presence of virulence markers and compared by XbaI DNA macrorestriction analysis using pulsed-field gel electrophoresis (PFGE). Each of 102 isolates tested contained the gene eae which encodes the E. coli attaching and effacing factor and all but one carried the enterohaemolysin gene, ehxA, found on the EHEC plasmid. The most common Shiga toxin gene carried was stx2c, either alone (16%) or in combination with stx1 (74%) or stx2 (3%). PFGE grouped the isolates based on H serotype and some clusters were source specific. Australian E. coli O157:H7 and H- isolates from human, animal and meat sources carry all the virulence markers associated with EHEC disease in humans therefore other factors must be responsible for the low rates of human infection in Australia.

scholarly journals Use of In Vivo-Induced Antigen Technology for Identification of Escherichia coli O157:H7 Proteins Expressed during Human Infection

2005 ◽  
Vol 73 (5) ◽  
pp. 2665-2679 ◽  
Author(s):  
Manohar John ◽  
Indira T. Kudva ◽  
Robert W. Griffin ◽  
Allen W. Dodson ◽  
Bethany McManus ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vaccine Development ◽  
Human Infection ◽  
Escherichia Coli O157 ◽  
Standard Laboratory ◽  
E Coli ◽  
Phase Culture ◽  
Stool Specimens

ABSTRACT Using in vivo-induced antigen technology (IVIAT), a modified immunoscreening technique that circumvents the need for animal models, we directly identified immunogenic Escherichia coli O157:H7 (O157) proteins expressed either specifically during human infection but not during growth under standard laboratory conditions or at significantly higher levels in vivo than in vitro. IVIAT identified 223 O157 proteins expressed during human infection, several of which were unique to this study. These in vivo-induced (ivi) proteins, encoded by ivi genes, mapped to the backbone, O islands (OIs), and pO157. Lack of in vitro expression of O157-specific ivi proteins was confirmed by proteomic analysis of a mid-exponential-phase culture of E. coli O157 grown in LB broth. Because ivi proteins are expressed in response to specific cues during infection and might help pathogens adapt to and counter hostile in vivo environments, those identified in this study are potential targets for drug and vaccine development. Also, such proteins may be exploited as markers of O157 infection in stool specimens.

scholarly journals Escherichia Coli O157:H7: Distribution, molecular characterization, antimicrobial resistance patterns and source of contamination of sheep and goat carcasses at an export Abattoir, Mojdo, Ethiopia

2019 ◽  
Author(s):  
Solomon Abreham ◽  
Akafete Teklu ◽  
Eric Cox ◽  
Tesfaye Sisay Tessema
Keyword(s):  
Escherichia Coli ◽  
Molecular Characterization ◽  
Virulence Genes ◽  
Antibiotic Sensitivity ◽  
Latex Agglutination ◽  
Human Infection ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Source Of Infection ◽  
Resistance Patterns

Abstract Background : Cattle have been identified as a major reservoir of E. coli O157:H7 for human infection; the ecology of the organism in sheep and goats is less understood. This study was carried out to determine prevalence, source of infection, antibiotic resistance and molecular characterization of Escherichia coli O157: H7 isolated from sheep and goat. Methods : Systematic random sampling was carried out at Modjo export abattoir, Ethiopia, from November 2012 to April 2013 to collect 408 samples from 72 sheep and 32 goats. Samples collected were skin swabs, fecal samples, intestinal mucosal swabs and the inside and outside part of carcasses as well as carcass in contacts such as workers hands, knife, hook and carcass washing water. Then, samples were processed following standard bacteriological procedures. Non-Sorbitol fermenting colonies were tested on latex agglutination test and the positives are subjected to PCR for detection of attaching and effacing genes ( eaeA) and shiga toxin producing genes ( stx1 and stx2 ). All E. coli O157:H7 isolates were checked for their susceptibility pattern towards 15 selected antibiotics. Results : E. coli O157:H7 were detected in only 20/408 samples (4.9%). Among these 20 positive samples, 70% (14/20), 25% (5/20) and 5% (1/20) were from sheep, goats and knife samples, respectively. No significant associations were found between carcasses and the assumed sources of contaminations. Of all the 20 isolates virulence genes were found in 10 (50%) of them; 3 (15%) with only the eaeA gene and 7(35%) expressing eaeA and stx2 genes. All the isolates were susceptible to Norfloxacin (NOR) (100%). Conclusions : The presence of virulence genes shows E. coli O157:H7 is a potential source of human infection in Ethiopia. Key words : Abattoir, antibiotic sensitivity, CT-SMAC, E. coli O157:H7, IMS, Latex agglutination, multiplex PCR.

scholarly journals Erratum

2002 ◽  
Vol 129 (2) ◽  
pp. 427-427
Author(s):  
T. E. BESSER ◽  
B. L. RICHARDS ◽  
D. H. RICE ◽  
D. D. HANCOCK
Keyword(s):  
Escherichia Coli ◽  
Direct Contact ◽  
Infectious Dose ◽  
Contact Transmission ◽  
Epidemiol Infect

Epidemiol. Infect.127 (2001), 555–60Escherichia coliO157: H7 infection of calves: infectious dose and direct contact transmissionPage 557, Figure 1(b). Replace with

scholarly journals Identification of Escherichia coli O157:H7 Genomic Regions Conserved in Strains with a Genotype Associated with Human Infection

2006 ◽  
Vol 73 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Marina Steele ◽  
Kim Ziebell ◽  
Yongxiang Zhang ◽  
Andrew Benson ◽  
Paulina Konczy ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Iron Transport ◽  
Subtractive Hybridization ◽  
Human Infection ◽  
Virulence Plasmid ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Conserved Regions ◽  
Genomic Regions

ABSTRACT Beta-glucuronidase-negative, sorbitol-nonfermenting isolates of Shiga toxin-producing Escherichia coli O157 comprise part of a clone complex of related enterohemorrhagic E. coli isolates. High-resolution genotyping shows that the O157 populations have diverged into two different lineages that appear to have different ecologies. To identify genomic regions unique to the most common human-associated genotype, suppression subtractive hybridization was used to identify DNA sequences present in two clinical strains representing the human lineage I O157:H7 strains but absent from two bovine-derived lineage II strains. PCR assays were then used to test for the presence of these regions in 10 lineage I strains and 20 lineage II strains. Twelve conserved regions of genomic difference for lineage I (CRDI) were identified that were each present in at least seven of the lineage I strains but absent in most of the lineage II strains tested. The boundaries of the lineage I conserved regions were further delimited by PCR. Eleven of these CRDI were associated with E. coli Sakai S-loops 14, 16, 69, 72, 78, 82, 83, 91 to 93, 153, and 286, and the final CRDI was located on the pO157 virulence plasmid. Several potential virulence factors were identified within these regions, including a putative hemolysin-activating protein, an iron transport system, and several possible regulatory genes. Cluster analysis based on lineage I conserved regions showed that the presence/absence of these regions was congruent with the inferred phylogeny of the strains.

scholarly journals Indirect Transmission of Escherichia coli O157:H7 Occurs Readily among Swine but Not among Sheep

2008 ◽  
Vol 74 (8) ◽  
pp. 2488-2491 ◽  
Author(s):  
Nancy A. Cornick ◽  
Hung VuKhac
Keyword(s):  
Escherichia Coli ◽  
Direct Contact ◽  
Infected Animal ◽  
Swine Manure ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Indirect Transmission ◽  
Pork Products ◽  
Infected Donor ◽  
Human Infections

ABSTRACT Transmission of Escherichia coli O157:H7 among reservoir animals is generally thought to occur either by direct contact between a naïve animal and an infected animal or by consumption of food or water containing the organism. Although ruminants are considered the major reservoir, there are two reports of human infections caused by E. coli O157:H7 linked to the consumption of pork products or to the contamination of fresh produce by swine manure. The objective of this study was to determine whether E. coli O157:H7 could be transmitted to naïve animals, both sheep and swine, that did not have any direct contact with an infected donor animal. We recovered E. coli O157:H7 from 10/10 pigs with nose-to-nose contact with the infected donor or animals adjacent to the donor and from 5/6 naïve pigs that were penned in the same room as the donor pig but 10 to 20 ft away. In contrast, when the experiment was repeated with sheep, E. coli O157:H7 was recovered from 4/6 animals that had nose-to-nose contact with the infected donor or adjacent animals and from 0/6 naïve animals penned 10 to 20 ft away from the donor. These results suggest that E. coli O157:H7 is readily transmitted among swine and that transmission can occur by the creation of contaminated aerosols.

Colonization of 8-week-old conventionally reared goats by Escherichia coli O157 : H7 after oral inoculation

2005 ◽  
Vol 54 (5) ◽  
pp. 485-492 ◽  
Author(s):  
R M La Ragione ◽  
N MY Ahmed ◽  
A Best ◽  
D Clifford ◽  
U Weyer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Large Intestine ◽  
Direct Contact ◽  
Distal Colon ◽  
Escherichia Coli O157 ◽  
Wild Type ◽  
E Coli ◽  
Goat’S Milk ◽  
Oral Inoculation ◽  
Strain Nctc

Enterohaemorrhagic Escherichia coli O157 : H7 infections of man have been associated with consumption of unpasteurized goat's milk and direct contact with kid goats on petting farms, yet little is known about colonization of goats with this organism. To assess the contribution of flagella and intimin of E. coli O157 : H7 in colonization of the goat, 8-week-old conventionally reared goats were inoculated orally in separate experiments with 1×1010 c.f.u. of a non-verotoxigenic strain of E. coli O157 : H7 (strain NCTC 12900 Nalr), an aflagellate derivative (DMB1) and an intimin-deficient derivative (DMB2). At 24 h after inoculation, the three E. coli O157 : H7 strains were shed at approximately 5×104 c.f.u. (g faeces)−1 from all animals. Significantly fewer intimin-deficient bacteria were shed only on days 2 (P = 0.003) and 4 (P = 0.014), whereas from day 7 to 29 there were no differences. Tissues from three animals inoculated with wild-type E. coli O157 : H7 strain NCTC 12900 Nalr were sampled at 24, 48 and 96 h after inoculation and the organism was cultured from the large intestine of all three animals and from the duodenum and ileum of the animal examined at 96 h. Tissues were examined histologically but attaching-effacing (AE) lesions were not observed at any intestinal site of the animals examined at 24 or 48 h. However, the animal examined at 96 h, which had uniquely shed approximately 1×107 E. coli O157 : H7 (g faeces)−1 for the preceding 3 days, showed a heavy, diffuse infection with cryptosporidia and abundant, multifocal AE lesions in the distal colon, rectum and at the recto-anal junction. These AE lesions were confirmed by immunohistochemistry to be associated with E. coli O157 : H7.

scholarly journals Greater Diversity of Shiga Toxin-Encoding Bacteriophage Insertion Sites among Escherichia coli O157:H7 Isolates from Cattle than in Those from Humans

2006 ◽  
Vol 73 (3) ◽  
pp. 671-679 ◽  
Author(s):  
Thomas E. Besser ◽  
Nurmohammad Shaikh ◽  
Nicholas J. Holt ◽  
Phillip I. Tarr ◽  
Michael E. Konkel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Diversity ◽  
Shiga Toxin ◽  
Insertion Site ◽  
Reservoir Host ◽  
Clinical Isolates ◽  
Escherichia Coli O157 ◽  
Human Pathogen ◽  
E Coli ◽  
Insertion Sites

ABSTRACT Escherichia coli O157:H7, a zoonotic human pathogen for which domestic cattle are a reservoir host, produces a Shiga toxin(s) (Stx) encoded by bacteriophages. Chromosomal insertion sites of these bacteriophages define three principal genotypes (clusters 1 to 3) among clinical isolates of E. coli O157:H7. Stx-encoding bacteriophage insertion site genotypes of 282 clinical and 80 bovine isolates were evaluated. A total of 268 (95.0%) of the clinical isolates, but only 41 (51.3%) of the bovine isolates, belonged to cluster 1, 2, or 3 (P < 0.001). Thirteen additional genotypes were identified in isolates from both cattle and humans (four genotypes), from only cattle (seven genotypes), or from only humans (two genotypes). Two other markers previously associated with isolates from cattle or with clinical isolates showed similar associations with genotype groups within bovine isolates; the tir allele sp-1 and the Q 933W allele were under- and overrepresented, respectively, among cluster 1 to 3 genotypes. Stx-encoding bacteriophage insertion site typing demonstrated that there is broad genetic diversity of E. coli O157:H7 in the bovine reservoir and that numerous genotypes are significantly underrepresented among clinical isolates, consistent with the possibility that there is reduced virulence or transmissibility to humans of some bovine E. coli O157:H7 genotypes.

scholarly journals Regional Immune Response to Immunization with Escherichia coli O157:H7-Derived Intimin in Cattle

2013 ◽  
Vol 20 (4) ◽  
pp. 562-571 ◽  
Author(s):  
Kathryn G. Boland ◽  
Andrea N. Hayles ◽  
Claire B. Miller ◽  
Tovah Kerr ◽  
Wendy C. Brown ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Immune Responses ◽  
Lymph Nodes ◽  
Effective Means ◽  
Human Infection ◽  
Escherichia Coli O157 ◽  
Content Type ◽  
E Coli ◽  
Local Responses ◽  
Human Infections

ABSTRACTEscherichia coliO157:H7 is an enteric pathogen of animals and humans that can result in deadly sequelae. Cattle are asymptomatic carriers and shedders of the bacteria and serve as an important reservoir of human infection.E. coliO157:H7 colonizes the gastrointestinal tract, most frequently at the rectoanal junction mucosa in cattle. Vaccination is a potentially highly effective means of decreasing cattle colonization and shedding and thereby decreasing human infections. Currently available vaccines are administered subcutaneously or intramuscularly, and immune responses have been evaluated solely by systemic immunoglobulin responses. This study evaluated local and systemic lymphoproliferative responses in addition to immunoglobulin responses following subcutaneous or mucosal (rectal) immunization withE. coliO157:H7 outer membrane protein intimin over three trials. In all three trials, significant local and systemic lymphoproliferative responses (P< 0.05) occurred following immunization in the majority of animals, as well as significant immunoglobulin responses (P< 0.001) in all animals. Surprisingly, local responses in the mesorectal lymph nodes were very similar between the subcutaneous and mucosal immunization groups. Moreover, the responses in mesorectal lymph nodes appeared targeted rather than generalized, as minimal or no significant responses were observed in the associated prescapular lymph nodes of subcutaneously immunized animals. The results indicate that both subcutaneous and mucosal immunizations are effective methods of inducing immune responses againstE. coliO157:H7 in cattle.

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