Influence of age, sex and herd characteristics on the occurrence of verocytotoxin-producing Escherichia coli O157 in Danish dairy farms

Nielsen, Eva Møller; Tegtmeier, Conny; Andersen, Hans Jørgen; Grønbæk, Carsten; Andersen, Jens S.

doi:10.1016/s0378-1135(02)00108-6

Cited by 71 publications

(56 citation statements)

References 21 publications

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“…The prevalence of vtx-positive animals among the 40 calves from two dairy cattle herds was high (88%). This age group has previously been identified to be the group with the highest prevalence of VTEC O157 excretion in Danish cattle herds (32). Studies from other countries have also found a higher prevalence of VTEC O157 in calves than in cows (17).…”

Section: Discussionmentioning

confidence: 66%

Detection and Characterization of Verocytotoxin-Producing Escherichia coli by Automated 5′ Nuclease PCR Assay

Nielsen¹,

Andersen²

2003

J Clin Microbiol

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183

142

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In recent years increased attention has been focused on infections caused by isolates of verocytotoxinproducing Escherichia coli (VTEC) serotypes other than O157. These non-O157 VTEC isolates are commonly present in food and food production animals. Easy detection, isolation, and characterization of non-O157 VTEC isolates are essential for improving our knowledge of these organisms. In the present study, we detected VTEC isolates in bovine fecal samples by a duplex 5 nuclease PCR assay (real-time PCR) that targets vtx1 and vtx2. VTEC isolates were obtained by colony replication by use of hydrophobic-grid membrane filters and DNA probe hybridization. Furthermore, we have developed 5 nuclease PCR assays for the detection of virulence factors typically present in VTEC isolates, including subtypes of three genes of the locus of enterocyte effacement (LEE) pathogenicity island. The 22 assays included assays for the detection of verocytotoxin genes (vtx1, vtx2), pO157-associated genes (ehxA, katP, espP, and etpD), a recently identified adhesin (saa), intimin (eae, all variants), seven subtypes of eae, four subtypes of tir, and three subtypes of espD. A number of reference strains (VTEC and enteropathogenic E. coli strains) and VTEC strains isolated from calves were tested to validate the PCR assays. The expected virulence profiles were detected for all reference strains. In addition, new information on the subtypes of LEE genes was obtained. For reference strains as well as bovine isolates, a consistent relationship between subtypes of the LEE genes was found, so that a total of seven different combinations of these were recognized (corresponding to the seven subtypes of eae). Isolates with 15 different serogroup-virulence profiles were isolated from 16 calves. Among these, 53% harbored LEE and 73% harbored factors carried by the large virulence plasmid. One LEE-negative isolate had the gene for the adhesin Saa. The most common virulence profile among the bovine isolates was vtx1, eae-, tir-␣, ehxA, and espP. This panel of assays offers an easy method for the extensive characterization of VTEC isolates.

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Section: Discussionmentioning

confidence: 66%

Detection and Characterization of Verocytotoxin-Producing Escherichia coli by Automated 5′ Nuclease PCR Assay

Nielsen¹,

Andersen²

2003

J Clin Microbiol

Self Cite

183

142

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“…However, the comparison of interference of probiotics strains at colonization of E. coli O157 and non-O157 between animals young and older is little studied. Usually the studies are made in cattle than sheep (Nielsen et al, 2002 ) or focusing just the reducing of shedding (Zhao et al, 1998;Lema et al, 2001;Kritas et al, 2006;Maragkoudakis et al, 2010). Strategies using probiotics strains into ruminant´s compartment to reduce the shedding of pathogenic microorganisms on the farm reducing thus the occurrence of diseases have been efficient according to some authors (ChaucheyrasDurant et al, 2010;Lema et al, 2001;Guarner and Malagelada, 2003).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of protective effect of probiotic in sheep against experimental infection by Escherichia coli

Rigobelo¹,

Maluta²,

Borges³

et al. 2013

Afr. J. Microbiol. Res.

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Domestic ruminants, especially sheep and cattle, are the main reservoirs of Shiga toxin-producingEscherichia coli (STEC) and may transmit this pathogen to human. Probiotics are "live organisms that, when administered in adequate amounts, confer a health benefit on the host", decreasing the infection and its dissemination. However, these benefits are conferred only after the colonization of probiotic strains in the gut of the animal, which may be impaired by normal microbiota. The aims of this study were to determine whether the inoculation of sheep with probiotic strains decreases the shedding of STEC and to determine whether the age of sheep interferes with this protective effect. Sheep that received oral inoculums at a concentration of 2 × 10 9 cells per mL of viable STEC bacteria, which are carriers of stx1, stx2 and eae genes, were compared with other sheep that did not receive inoculums. When probiotic bacteria were inoculated together with the STEC, the number of pathogenic bacteria in the population was similar to the control. The protective effect of probiotic strains was largest in groups with younger animals than with older animals. These findings suggest that the use of probiotic strains in sheep may decrease the intestinal shedding by STEC as well as the fact that the age of the sheep may interfere in the protective effect of probiotics against colonization by STEC.

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“…There are many papers reporting the colonisation of the gastrointestinal tract of both large and small ruminants with STEC serotypes (Kudva et al, 1996;Blanco et al, 1997;Nielsen et al, 2002). The direct relationship between the STEC shed by small ruminants or the presence of the bacteria in their products on the one hand and human infections on the other has been, however, demonstrated only sporadically (Bielaszewska et al, 1997;Chapman et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Isolation and characterization Shiga toxin-producing Escherichia coli from sheep and goats inJordanwith evidence of multiresistant serotype O157:H7

Novotná¹,

Alexa²,

Hamrik³

et al. 2005

Vet. Med. - Czech

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Ninety-three rectal swabs of lambs and young goats from two extensively and two intensively managed herds in Jordan were taken and examined for Shiga toxin-producing Escherichia coli (STEC). The bacteriological examination included the preenrichment of rectal swabs in EC broth with novobiocin, and a subsequent parallel isolation on enterohemolysin agar and immunomagnetic separation with cultivation on CT-SMAC. The STEC O157:H7 strains were demonstrated in 8 of 32 diarrheic lambs 1-to 3-weeks old in one sheep herd with intensive milk production. In the remaining three herds, serogroups O128, O78, O15 and serotype O128:K85 of STEC strains were the most frequent findings. The presence of stx2, ehlyA and eaeA genes in all STEC O157:H7 isolates was confirmed by PCR. In two untypable STEC isolates, stx2 and ehlyA genes were detected. In other STEC non-O157 isolates, only stx1 a ehlyA genes were found. All STEC O157:H7 isolates were resistant against sulphonamides and chloramphenicol, five were also resistant against ampicillin and streptomycin, one against co-trimoxazole. One isolate was resistant against ampicillin, ampicillin-sulbactam, cephalosporins (cefazolin, cefuroxime), monobactams (aztreonam), sulphonamides, co-trimoxazole, aminoglycosides, tetracycline and chloramphenicol. Compared the resistant STEC O157:H7 isolates, the multiresistant isolate had a different RAPD pattern. Of 36 STEC non-O157 isolates, one isolate was resistant against sulphonamides and co-trimoxazole, and another one against ampicillin, streptomycin, sulphonamides and co-trimoxazole. STEC isolates resistant against antimicrobial agents were demonstrated only in herds with intensive management.

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Influence of age, sex and herd characteristics on the occurrence of verocytotoxin-producing Escherichia coli O157 in Danish dairy farms

Cited by 71 publications

References 21 publications

Detection and Characterization of Verocytotoxin-Producing Escherichia coli by Automated 5′ Nuclease PCR Assay

Detection and Characterization of Verocytotoxin-Producing Escherichia coli by Automated 5′ Nuclease PCR Assay

Evaluation of protective effect of probiotic in sheep against experimental infection by Escherichia coli

Isolation and characterization Shiga toxin-producing Escherichia coli from sheep and goats inJordanwith evidence of multiresistant serotype O157:H7

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