The shift of genetic subtypes of <i>Escherichia coli</i> O157[ratio   ]H7 
isolates from cattle

Akiba, Masato; Sameshima, Toshiya; Nakazawa, Muneo

doi:10.1017/s0950268899002204

Cited by 25 publications

(33 citation statements)

References 12 publications

(18 reference statements)

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“…It is unclear whether the source was of bovine or human origin, since both cattle and humans can excrete multiple subtypes (2,3,10,28). One hypothesis is that cow manure contaminated with E. coli O157:H7 was carried into the dormitory on muddy boots, was washed into the septic system, and subsequently seeped into well 6 (Ackelsberg et al, unpublished data).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, the predominant PFGE patterns, 1 and 1a, have rarely been detected by our laboratory, suggesting that this outbreak originated primarily from a single genetically related strain. Studies have demonstrated that multiple subtypes can be shed from both bovine and human infections (2,3,10,28). Although this is often explained by a loss of either the 60-MDa plasmid or the bacteriophage harboring the Shiga toxin genes, the exact mechanisms involved are unclear.…”

Section: Discussionmentioning

confidence: 99%

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Detection, Isolation, and Molecular Subtyping of Escherichia coli O157:H7 and Campylobacter jejuni Associated with a Large Waterborne Outbreak

et al. 2003

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The largest reported outbreak of waterborne Escherichia coli O157:H7 in the United States occurred in upstate New York following a county fair in August 1999. Culture methods were used to isolate E. coli O157:H7 from specimens from 128 of 775 patients with suspected infections. Campylobacter jejuni was also isolated from stools of 44 persons who developed diarrheal illness after attending this fair. There was one case of a confirmed coinfection with E. coli O157:H7 and C. jejuni. Molecular detection of stx 1 and stx 2 Shiga toxin genes, immunomagnetic separation (IMS), and selective culture enrichment were utilized to detect and isolate E. coli O157:H7 from an unchlorinated well and its distribution points, a dry well, and a nearby septic tank. PCR for stx 1 and stx 2 was shown to provide a useful screen for toxin-producing E. coli O157:H7, and IMS subculture improved recovery. Pulsed-field gel electrophoresis (PFGE) was used to compare patient and environmental E. coli O157:H7 isolates. Among patient isolates, 117 of 128 (91.5%) were type 1 or 1a (three or fewer bands different). Among the water distribution system isolates, 13 of 19 (68%) were type 1 or 1a. Additionally, PFGE of C. jejuni isolates revealed that 29 of 35 (83%) had indistinguishable PFGE patterns. The PFGE results implicated the water distribution system as the main source of the E. coli O157:H7 outbreak. This investigation demonstrates the potential for outbreaks involving more than one pathogen and the importance of analyzing isolates from multiple patients and environmental samples to develop a better understanding of bacterial transmission during an outbreak.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Detection, Isolation, and Molecular Subtyping of Escherichia coli O157:H7 and Campylobacter jejuni Associated with a Large Waterborne Outbreak

et al. 2003

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“…However, this differs from the findings of LeClerc et al (18) suggesting that some O157 strains may become hypermutable, making them more adaptable to changing environments and increasing the organism's genetic diversity. Also, a Japanese study (1) reported the shift of genetic subtypes on one farm and from one animal. Although there is some evidence that clonal turnover , X43 2 52 X1, X2, X3, X4, X12, X15, X16, X39, X44, X45 3 35 X5, X19, X20, X21, X24, X26, X30, X32, X33, X36, X37, X40, X41 4 26 X46, X47, X48, X49, X50, X51, X52, X53, X54, 5 8 X7, X31, X54, X56 6 9 X10, X22, X42, X54 7 1 X13 8 29 X8, X11, X25, X30, X59 9 54 X17, X23, X24, X26, X27, X28, X34, X35, X38 10 4 X24, X36 11 7 X6, X8, X9, X18 and genetic rearrangement remain rare under environmental situations, it is possible that this is faster in situ than in the laboratory (12).…”

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confidence: 99%

Genetic Diversity among Escherichia coli O157:H7 Isolates from Bovines Living on Farms in England and Wales

Liébana¹,

Smith

Lindsay

et al. 2003

J Clin Microbiol

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Pulsed-field gel electrophoresis of Escherichia coli O157:H7 isolates (n ‫؍‬ 228) from 122 healthy animals on 11 farms discriminated 57 types. Most clones were found only on individual farms. Numerous clones were found within each farm, with a prevalent clone normally found in several animals. A variety of clones were found within the different phage types.Escherichia coli strains that produce Shiga-like toxins may produce two toxins (Shiga toxin 1 [ST1] and/or ST2) with similar biological activities. A subset of Shiga-toxigenic E. coli strains designated as enterohemorrhagic (EHEC) carry sets of virulence genes (e.g., eaeA) that encode factors for attachment to host cells. Recent studies have revealed the existence of two divergent lineages (EHEC 1 and 2) (25). The EHEC 1 lineage consists solely of a few very closely related and geographically disseminated multilocus genotypes each bearing the O157 phenotype (15). Despite this similarity, pulsed-field gel electrophoresis (PFGE) and other molecular techniques have shown a considerable degree of genetic heterogeneity among O157 isolates in several countries, suggesting large evolutionary distances between strains. PFGE is considered the "gold standard" for fingerprinting of O157 strains and forms the basis of a large surveillance database (PulseNet) (24).Cattle are important reservoirs for this agent. Limited information is available about the genetic diversity of O157:H7 animal strains in the United Kingdom. Several studies have looked at human outbreak isolates, in most cases from Scotland (2,3,16,23). Some studies have described diversity in plasmid profiles in a limited number of animal isolates in comparison with isolates from food and humans (6,8,9). To our knowledge, one recent study (5) was the first to investigate the diversity of genotypes among animal isolates. The aim of the present study was to evaluate the genotypic diversity of O157:H7 isolates on a variety of cattle farms.Bacterial strains. E. coli O157:H7 (666 isolates) was cultured (7) (14) at 100 ng each, 2.5 mM MgCl 2 , and 2 l of bacterial DNA template. The PCR run consisted of 95°C for 10 min (one cycle), followed by 35 cycles of 95°C for 10 s, 65°C for 5 s, and 72°C for 25 s. The nature of the amplicon was determined by melting analysis over a temperature range from 70 to 97°C (0.1°C/s), and the melting temperature (T m ) was 87.5°C. The size of the product (625 bp) was verified by gel electrophoresis.

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“…In addition, in the case of PFGE, the changing of a few bands during cultivation of the STEC strain, even between the same clones, has been observed (14,51). It has been also reported that RFLP patterns of PFGE change even after strain passage through cow or human gastrointestinal tract (1,2,21). If the Region V in the Stx phage is stable, this can be averted.…”

Section: Fig 3 (A)mentioning

confidence: 96%

Development of a PCR-Restriction Fragment Length Polymorphism Assay for the Epidemiological Analysis of Shiga Toxin-Producing Escherichia coli

et al. 2004

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Six characteristic regions (I to VI) were identified inTo evaluate the PCR-RFLP assay developed here, ten strains, each isolated from four different outbreaks in different areas in Japan (Tochigi, Hyogo, Aichi, and Fukuoka prefecture), were examined to determine whether the strains in each group showed the same RFLP patterns in the PCR-RFLP assay. In accordance with the results of PFGE except for strains isolated in an area (Fukuoka), which did not produce any amplicon, ten strains in each group demonstrated the same RFLP pattern. Taken together, these data suggest that the PCR-RFLP based on region V is as useful as PFGE but perhaps more simple and rapid than PFGE for the molecular epidemiological analysis of STEC strains during sporadic and common source outbreaks.

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The shift of genetic subtypes of Escherichia coli O157[ratio ]H7 isolates from cattle

Cited by 25 publications

References 12 publications

Detection, Isolation, and Molecular Subtyping of Escherichia coli O157:H7 and Campylobacter jejuni Associated with a Large Waterborne Outbreak

Detection, Isolation, and Molecular Subtyping of Escherichia coli O157:H7 and Campylobacter jejuni Associated with a Large Waterborne Outbreak

Genetic Diversity among Escherichia coli O157:H7 Isolates from Bovines Living on Farms in England and Wales

Development of a PCR-Restriction Fragment Length Polymorphism Assay for the Epidemiological Analysis of Shiga Toxin-Producing Escherichia coli

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