Use of tellurite for the selection of verocytotoxigenic Escherichia coli O157

Zadik, P.; Chapman, P. A.; Siddons, C. A.

doi:10.1099/00222615-39-2-155

Cited by 312 publications

(198 citation statements)

References 22 publications

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“…Media used were buffered peptone water (CM509, Oxoid, Basingstoke) unmodified (BPW) or supplemented with vancomycin 8 mg/l, cefixime 0 05 mg/l and cefsulodin 10 mg/l (BPW-VCC [4]); nutrient broth (No. 2, Oxoid, Basingstoke); sorbitol MacConkey agar (CM813, Oxoid, Basingstoke) unmodified (SMAC) or supplemented with cefixime 0 05 mg/l and potassium tellurite 2-5 mg/l (CT-SMAC [8]); and plate count agar (LAB 149, Lab M, Bury). Magnetic beads coated with an antibody against E. coli 0157 (Dynabeads anti-E. coli 0157) were supplied by Dynal AS, Oslo.…”

Section: Methodsmentioning

confidence: 99%

“…However, SMAC medium relies entirely on differential sugar fermentation and does not select VT' E. coli 0157 from other E. coli or sorbitol non-fermenting genera and therefore lacks sensitivity. Improvements to the selectivity of SMAC [7,8] have resulted in increased sensitivity of isolation of E. coli 0157 from faecal samples, but are not sufficiently sensitive for isolation of small numbers of the organisms from food and environmental samples.…”

Section: Isolation Of E Coli 0157 From Minced Beefmentioning

confidence: 99%

“…Improvements to sorbitol MacConkey medium [7,8] have resulted in increased sensitivity of isolation of E. coli 0157 from faecal samples, and enrichment culture in buffered peptone water with vancomycin, cefsulodin and cefixime has been effective for isolating the organism from carcass meat samples [4]. However, the detection of E. coli 0157 present in low numbers in environmental samples is a problem due to the low sensitivity of enrichment and direct culture methods currently available.…”

Section: Introductionmentioning

confidence: 99%

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Immunomagnetic separation as a sensitive method for isolatingEscherichia coliO157 from food samples

Wright¹,

Chapman²,

Siddons³

1994

Epidemiol. Infect.

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181

101

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SUMMARYMinced beef samples inoculated with Escherichia coli 0157 were cultured in buffered peptone water supplemented with vancomycin, cefsulodin and cefixime (BPW-VCC) and subcultured to cefixime tellurite sorbitol MacConkey (CT-SMAC) agar both directly and after immunomagnetic separation (IMS) of the organism with magnetic beads coated with an antibody against E. coli 0157 (Dynabeads anti-E. coli 0157, Dynal, Oslo). E. coli 0157 was recovered from initial inocula of 200 organisms/g by direct subculture and 2 organisms/g by IMS. Twelve strains of E. coli 0157 of different combinations of phage type, H antigen and toxin genotype were all recovered from initial inocula of two organisms/g by IMS. Nonspecific binding of other organisms to the magnetic beads could be reduced by washing of the beads in PBS with Tween-20 0.002-0.005% E. coli 0157 was not bound by magnetic coated with an unrelated antibody.During investigation of a dairy herd that was possibly linked to a small outbreak of infection with E. coli 0157, the organism was isolated from 2 of 279 forestream milk samples from individual cattle; both isolates were made only by the IMS technique. IMS is rapid, technically simple, and a specific method for isolation of E. coli 0157 and will be useful in epidemiological studies.

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Section: Methodsmentioning

confidence: 99%

Section: Isolation Of E Coli 0157 From Minced Beefmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Immunomagnetic separation as a sensitive method for isolatingEscherichia coliO157 from food samples

Wright¹,

Chapman²,

Siddons³

1994

Epidemiol. Infect.

Self Cite

181

101

View full text Add to dashboard Cite

show abstract

“…During investigation of sporadic infections and outbreaks, stools from asymptomatic contacts were sometimes tested for carriage of E. coli O157. Faecal samples were plated on Sorbitol MacConkey agar (SMAC), or SMAC containing ce®x-ime 0:05 mg=L and potassium tellurite 2:5 mg=L (CT-SMAC) and putative E. coli O157 were identi®ed as sorbitol non-fermenting colonies after incubation for 18 h at 378C [25,26]. Colonies were tested for agglutination with anti-O157 serum or anti-O157 latex agglutination kits and identi®ed biochemically as presumptive E. coli with commercially available tests before referral to the Laboratory of Enteric Pathogens (LEP).…”

Section: Isolation Of E Coli O157 In Diagnostic Laboratoriesmentioning

confidence: 99%

Verocytotoxin-producing Escherichia coli (VTEC) O157 and other VTEC from human infections in England and Wales: 1995–1998

Willshaw¹,

Cheasty²,

Smith³

et al. 2001

Journal of Medical Microbiology

116

126

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A total of 3429 isolations of verocytotoxin-producing Escherichia coli O157 (VTEC O157) was con®rmed from human sources in England and Wales during the period 1995±1998. The largest annual total was 1087 in 1997. Most infections occurred in the third quarter of each year. The overall rate of infection ranged from 1.28 to 2.10=100 000 population and showed regional variation. The highest incidence was in children aged 1±4 years. Annually, between 5% and 11% of strains were from patients who had travelled abroad. There were 67 general outbreaks of infection represented by 407 (11.9%) VTEC O157 isolates. Outbreaks involved transmission by contaminated food or water, person-toperson spread and direct or indirect animal contact, and ®ve were associated with foreign travel. The majority (76%) of strains carried verocytotoxin (VT) 2 genes and 23.3% were VT1 VT2. Most strains had the¯agellar antigen H7, but c. 14% were non-motile. Approximately 20% of isolates were resistant to antimicrobial agents, predominantly streptomycin, sulphonamides and tetracycline. In addition to VTEC O157, strains of serogroup O157 that did not possess VT genes were identi®ed. These were either derivatives of VTEC O157 that had lost VT genes or were strains with H antigens other than H7 that have never been associated with VT production. Strains of VTEC other than O157 were characterised. Most were associated with diarrhoea, bloody diarrhoea or haemolytic uraemic syndrome and had virulence markers in addition to VT.

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“…About 10 g of faecal sample was added to 100 ml of mEC broth containing 20 µg/ml novobiocin [18]. After 18 hr of incubation at 42°C, 10 µl was inoculated on CT-SMAC agar [24] and incubated at 37°C for 18 to 20 hr. Sorbitol-nonfermenting colonies were selected and regarded as EHEC.…”

mentioning

confidence: 99%

High Prevalence of Enterohemorrhagic Escherichia coli (EHEC) O157 from Cattle in Selected Regions of Japan

Ezawa

Gocho

Kawata

et al. 2004

The Journal of Veterinary Medical Science

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ABSTRACT. The prevalence of enterohemorrhagic Escherichia coli (EHEC) O157 was examined in bovine faeces. EHEC O157 was isolated from the faeces of 42 (13.0%) of 324 cattle. Of the 4 farms and the facilities tested, the 3 farms and the facilities wer e found positive for EHEC O157. The highest isolation rate among the farms was 33.7%. The prevalence of EHEC O157 in heifers was higher than that in calves and other cattle. No cattle positive for EHEC O157 showed any clinical signs except 2 calves with diarrhea in a veterinary hospital. Almost all isolates possessed the stx gene, and Stx-positive strains carrying both stx 1 and stx 2 genes were predominant. These results indicate that EHEC O157 are distributed in bovine faeces, and that dairy and beef farms in selected regions of Japan are heavily contaminated with the organisms. KEY WORDS: cattle, EHEC O157, prevalence.

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Use of tellurite for the selection of verocytotoxigenic Escherichia coli O157

Cited by 312 publications

References 22 publications

Immunomagnetic separation as a sensitive method for isolatingEscherichia coliO157 from food samples

Immunomagnetic separation as a sensitive method for isolatingEscherichia coliO157 from food samples

Verocytotoxin-producing Escherichia coli (VTEC) O157 and other VTEC from human infections in England and Wales: 1995–1998

High Prevalence of Enterohemorrhagic Escherichia coli (EHEC) O157 from Cattle in Selected Regions of Japan

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