Screening petting zoo animals for the presence of potentially pathogenic Escherichia coli.
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Several outbreaks of Escherichia coli O157 have been reported in petting zoos, resulting in hospitalization of many children. At present, no standard procedure has been adopted to monitor the presence of enterohemorrhagic E. coli (EHEC) or Shiga-toxin-producing E. coli (STEC) in petting zoo animals. Direct detection of these strains from rectal swabs of animals in petting zoos was developed and obviated the need to culture the organisms. DNA extracted from bacteria in the swabs was tested for the presence of wecA gene specific for E. coli by polymerase chain reaction (PCR). The wecA positive samples were further tested for Shiga-toxin genes stxl and stx2, and the intimin eae by multiplex PCR and for the presence of O157 and H7. Swabs (n=104) from 15 animal species in a petting zoo were tested; 7 goats and 3 cows were found to carry STEC. The method is rapid and convenient for monitoring potentially pathogenic E. coli in petting zoo animals. (+info)
Modelling the epidemiology and transmission of Verocytotoxin-producing Escherichia coli serogroups O26 and O103 in two different calf cohorts.
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Mathematical models are constructed to investigate the population dynamics of Verocytotoxin-producing Escherichia coli (VTEC) serogroups O26 and O103 in two different calf cohorts. We compare the epidemiological characteristics of these two serogroups within the same calf cohort as well as the same serogroups between the two calf cohorts. The sources of infection are quantified for both calf cohort studies. VTEC serogroups O26 and O103 mainly differ in the rate at which calves acquire infection from sources other than infected calves, while infected calves typically remain infectious for less than 1 week regardless of the serogroups. Fewer than 20% of VTEC-positive samples are the result of calf-to-calf transmission. PFGE typing data are available for VTEC-positive samples to further subdivide the serogroup data in one of the two calf cohort studies. For serogroup O26 but not O103, there is evidence for unequal environmental exposure to infection with different PFGE types. (+info)
Public farms: hygiene and zoonotic agents.
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In three successive years, we visited petting farms (n=132), care farms (n=91), and farmyard campsites (n=84), respectively, and completed a standard questionnaire with the objective of determining the hygienic status of these farms and describing hygiene measures implemented to reduce the risk of transmission of zoonotic agents from the animals to humans. For at least 85% of the farms, the overall impression of hygiene was recorded as good. However, more attention must be paid to: informing visitors on hygiene and handwashing, provision of handwashing facilities, and a footwear cleaning facility. Examination of samples of freshly voided faeces resulted in the detection of Shiga toxin-producing Escherichia coli O157 and/or Salmonella spp. and/or Campylobacter spp. at almost two-thirds (64.9%) of the petting farms, and around half of the care farms (56.0%) and farmyard campsites (45.2%). These data reinforce the need for control measures for both public and private farms to reduce human exposure to livestock faeces and thus the risk of transmission of zoonotic diseases. Public awareness of the risk associated with handling animals or faecal material should be increased. (+info)
Tracing shigatoxigenic Escherichia coli O103, O145, and O174 infections from farm residents to cattle.
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Severe diarrheal infections caused by Shigatoxigenic Escherichia coli O103:H2:stx(1):eae-epsilon:ehx, O145:H28:stx(1):eae-gamma:ehx (two cases in a family), and O174:H21:stx(2c) in farm residents were traced to cattle. Molecular methods were applied to the isolation and characterization of the strains. The causative strains were also isolated from cattle samples 1 or 4 months later. (+info)
Isolation and genetic characterization of a coinfection of non-O157 Shiga toxin-producing Escherichia coli.
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A coinfection of O177:NM and O55:H7 Shiga toxin-producing Escherichia coli (STEC) was identified for a child with acute bloody diarrhea and hemolytic uremic syndrome by using culture and serotype-specific molecular reagents. The profile of O157-related genetic islands revealed that the O55:H7 isolate was highly similar to O157 STEC whereas the O177:NM isolate lacked several fimbrial O islands and non-locus-of-enterocyte-effacement effector determinants. However, both STEC serotypes are known to cause serious disease, and the significant repertoire of virulence determinants in both strains made it impossible to determine their individual contributions to the clinical symptoms. (+info)
Multilocus characterization scheme for shiga toxin-encoding bacteriophages.
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Shiga toxin-producing Escherichia coli (STEC) strains are food-borne pathogens whose ability to produce Shiga toxin (Stx) is due to integration of Stx-encoding lambdoid bacteriophages. These Stx phages are both genetically and morphologically heterogeneous, and here we report the design and validation of a PCR-based multilocus typing scheme. PCR primer sets were designed for database variants of a range of key lambdoid bacteriophage genes and applied to control phages and 70 stx(+) phage preparations induced from a collection of STEC isolates. The genetic diversity residing within these populations could be described, and observations were made on the heterogeneity of individual gene targets, including the unexpected predominance of short-tailed phages with a highly conserved tail spike protein gene. Purified Stx phages can be profiled using this scheme, and the lambdoid phage-borne genes in induced STEC preparations can be identified as well as those residing in the noninducible prophage complement. The ultimate goal is to enable robust and realistically applicable epidemiological studies of Stx phages and their traits. The impact of Stx phage on STEC epidemiology is currently unknown. (+info)
Evaluation of vt2-subtyping methods for identifying vt2g in verotoxigenic Escherichia coli.
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Verotoxin-producing Escherichia coli (VTEC) are important pathogens that can cause severe human disease, including haemorrhagic colitis and haemolytic-uraemic syndrome. A new variant of verotoxin, vt2g, has recently been described. It was possible to find this variant for the first time in Argentina among VTEC isolated from cattle. The present study evaluated the identification of this gene with three conventional methods used for subtyping the vt2 gene. The results show that it is possible to screen VTEC strains for the presence of vt2g without the implementation of new protocols. (+info)
Shiga toxin gene-containing Escherichia coli from cattle and diarrheic children in the pastoral systems of southwestern Uganda.
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Shiga toxin-producing Escherichia coli (STEC) strains from cattle and diarrheic children in a pastoralist community in Uganda were investigated. The STEC strains belonged to a variety of different serogroups, and 70% of the strains were positive for the intimin gene, eae. STEC strains from two of the children were closely related to bovine strains. (+info)