Distribution of Intimin Subtypes among<i>Escherichia coli</i>Isolates from Ruminant and Human Sources

Ramachandran, Vidiya; Brett, Kim N.; Hornitzky, M.; Dowton, Mark; Bettelheim, K. A.; Walker, Mark J.; Djordjevic, Steven P.

doi:10.1128/jcm.41.11.5022-5032.2003

Cited by 114 publications

(127 citation statements)

References 54 publications

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“…The restriction fragments were separated by agarose gel electrophoresis and visualized using ethidium bromide staining. To determine which intimin type was present in each isolate, the resulting RFLP patterns were compared to published RFLP profiles (64).…”

Section: Methodsmentioning

confidence: 99%

“…Molecular characterization of intimin variants. All intimin-positive STEC isolates were further characterized using intimin typing as described by Ramachandran and colleagues (64). Briefly, a single forward primer (EaeVF) and 3 reverse primers (EaeVR, EaeZetaVR, and EaeIotaVR) (Eurofins MWG Operon, Ebersberg, Germany) ( Table 2) were used to amplify an 834-to 876-bp fragment (size varied depending on the variant) representing the 3Ј-variable regions of all reported intimin variants.…”

Section: Methodsmentioning

confidence: 99%

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Serotypes and Virulence Profiles of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Bovine Farms

Monaghan

Byrne

Fanning

et al. 2011

Appl Environ Microbiol

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Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains are clinically significant food-borne pathogens. However, there is a dearth of information on serotype prevalence and virulence gene distribution, data essential for the development of public health protection monitoring and control activities for the meat and dairy industries. Thus, the objective of this study was to examine the prevalence of non-O157 STEC on beef and dairy farms and to characterize the isolates in terms of serotype and virulence markers. Bovine fecal samples (n ‫؍‬ 1,200) and farm soil samples (n ‫؍‬ 600) were collected from 20 farms throughout Ireland over a 12-month period. Shiga toxin-positive samples were cultured and colonies examined for the presence of stx 1 and/or stx 2 genes by PCR. Positive isolates were serotyped and examined for a range of virulence factors, including eaeA, hlyA, tir, espA, espB, katP, espP, etpD, saa, sab, toxB, iha, lpfA O157/OI-141 , lpfA O113 , and lpfA O157/OI-154 . Shiga toxin and intimin genes were further examined for known variants. Significant numbers of fecal (40%) and soil (27%) samples were stx positive, with a surge observed in late summer-early autumn. One hundred seven STEC isolates were recovered, representing 17 serotypes. O26:H11 and O145:H28 were the most clinically significant, with O113:H4 being the most frequently isolated. However, O2:H27, O13/O15:H2, and ONT:H27 also carried stx 1 and/or stx 2 and eaeA and may be emerging pathogens.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Serotypes and Virulence Profiles of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Bovine Farms

Monaghan

Byrne

Fanning

et al. 2011

Appl Environ Microbiol

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“…The strains that are eae-positive but vtx-negative may be less likely than verocytotoxin-positive strains to cause human disease (Ramachandran et al, 2003). Verocytotoxin-positive isolates were particularly identified in E. coli O26 : H11 where 11 samples carried strains possessing vtx, eae and hlyA virulence genes.…”

Section: Similarity Of Isolates To Those Causing Human Infectionsmentioning

confidence: 98%

Prevalence of Escherichia coli O157 : H7 and serogroups O26, O103, O111 and O145 in sheep presented for slaughter in Scotland

Evans

Knight

McKendrick

et al. 2011

Journal of Medical Microbiology

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Sheep have been proposed as a source of human verocytotoxigenic Escherichia coli infection on a number of occasions but few prevalence studies have focused on identifying rates of carriage of these pathogens in this species. The purpose of this work was to establish the frequency of excretion of E. coli of serogroups O157, O26, O103, O111 and O145 in sheep presented for slaughter in Scotland and to examine their carriage of known virulence determinants. The study involved microbiological isolation of E. coli from 1082 sheep presented for slaughter in four Scottish abattoirs between July 2005 and June 2006. Using faecal enrichment and immunomagnetic separation, the isolation rate from these samples was 3.4 % for E. coli serogroup O157, 5.2 % for E. coli serogroup O26, 2.3 % for E. coli serogroup O103 and 0.1 % for E. coli serogroup O145. E. coli O111 was not isolated. In the last month of testing, which coincided with sorbitol-fermenting E. coli O157 (SFO157) cases in children in Scotland, all 83 recta received were screened and tested negative for SFO157 strains. The study found no verocytotoxin-positive strains amongst the E. coli serogroup O103 or O145 isolates. Verocytotoxin-positive strains were identified amongst isolates of E. coli serotypes O157 : H7 and O26 : H11. E. coli O157 : H7 was not isolated from samples collected between January and March, a statistically significant drop (P,0.001) in mean shedding relative to other months. There was evidence (P50.003) of higher shedding of O157 in adults and hoggs than in lambs. E. coli O26 : H11 was isolated throughout the year, with a statistically significant peak in shedding in the third quarter (P50.003). The results showed that sheep presented for slaughter in Scotland may carry strains of E. coli, particularly of serogroups O157 and O26, which can be presumed to have potential to cause human infection. They did not support a hypothesis that human cases of E. coli O157 : H7 are higher in any particular Scottish region as a direct consequence of a higher rate of faecal carriage in sheep in that region. INTRODUCTIONEscherichia coli strains that produce verocytotoxins are important pathogens causing human illnesses ranging from diarrhoea to haemorrhagic colitis and haemolytic uraemic syndrome (Karmali, 1989;Riley, 1987). In the UK, North America, Japan and much of continental Europe, such disease is commonly caused by E. coli strains of serogroup O157 (Riley et al., 1983;Kleanthous et al., 1990;Willshaw et al., 2001;Kaper et al., 2004;Chase-Topping et al., 2008).A variety of infection routes, including food-borne transmission and person-to-person spread, have been described, but in the UK, human infections by E. coli O157 are also recognized arising from direct contact with animal reservoirs (Locking et al., 2001;O'Brien et al., 2001). Examples of where infection has been specifically associated with sheep include: illness linked with lambing ewes (Allison et al., 1997); sheep faeces apparently contaminating the water supply at a campsite outbreak (Licence et...

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“…The N-terminal region is conserved among the different intimin subtypes, while the C-terminal regions are highly variable. The 29 intimin subtypes are identified according to their C-terminal amino acid sequences [40][41][42][43][44][45][46]. Intimin-β is the most common subtype expressed in EPEC isolates [44][45][46]56].…”

Section: Immunogenicity and Efficacy Of A Roughmentioning

confidence: 99%

Vaccine Against Entheropathogenic E. colii: A Systematic Review

Vasconcellos¹,

Silva²,

Nascimento³

et al. 2017

IJVR

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Enteric diseases are a major cause of childhood death in the developing world, ranking as the second cause of death in children. Enteropathogenic Escherichia coli(EPEC) are important diarrheal pathogens of children under 5 years of age. Due to high mortality, several international organizations such as the WHO and UNICEF have dedicated preventive and control programs for diarrheal diseases. Among the suggested initiatives aiming to prevent infectious diarrhea include vaccine development and improvement in sanitation and water and food supplies.Upon contact with host cells, EPEC delivers an array of virulence protein factors, which integrated actions interferes with the normal adjusting the targets molecular cell functions leading to diarrhea. The locus of entherocyte effacement (LEE)pathogenicity island contains genes encoding synthesis of the EPEC virulence factors membrane adhesin intimin, T3SS (Esc and Sep proteins), chaperones (Ces proteins), translocators (EspA, EspB, and EspD), effector proteins (EspF, EspG, EspH, Map and EspZ), the translocated intimin receptor (Tir), and the regulatory protein Ler (LEEencoded regulator).Bundle-forming pilus (BfpA) is another virulence factor that mediates the initial contact between EPEC and the host cell. BfpA is encoded by a gene localized on a 50-70 MDa plasmid and is designated as EPEC adherence factor (EAF). BfpA, intimin and translocated Tir initiate EPEC infection. This repertoire of virulence factors offers strategic epitopes as vaccine candidates.Employing the proposed technologies for modern vaccines, recombinant Mycobacterium smegmatis (Smeg) and Mycobacterium bovis BCG strains were constructed to express BfpA, intimin and EspA. Recombinant clones were selected based on kanamycin resistance. Recombinant proteins are immunogenic, and the resultant antibodies recognize and block EPEC adhesion onto HEp-2 target cells. In attention to regulatory agency recommendations, kanamycin should not be used to produce rBCG expressing the E. coli EPEC virulence factors BfpA, intimin and EspA. Accordingly, an expression system with a Pasteur auxotrophic BCG mutant for leucine (BCG Pasteur ΔleuD) and a replicative vector (pUP410)should be used. Obtained recombinants will be grown in large scale, and their immunogenic effectivity and human safety submitted to WHO indicated quality controls.

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Distribution of Intimin Subtypes amongEscherichia coliIsolates from Ruminant and Human Sources

Cited by 114 publications

References 54 publications

Serotypes and Virulence Profiles of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Bovine Farms

Serotypes and Virulence Profiles of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Bovine Farms

Prevalence of Escherichia coli O157 : H7 and serogroups O26, O103, O111 and O145 in sheep presented for slaughter in Scotland

Vaccine Against Entheropathogenic E. colii: A Systematic Review

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