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Volume 3, Number 4—December 1997


Vero Cytotoxin-Producing Escherichia coli O157 Outbreaks in England and Wales, 1995: Phenotypic Methods and Genotypic Subtyping

Geraldine A. Willshaw*, Henry R. Smith*, Thomas Cheasty*, Patrick G. Wall†, and Bernard Rowe*
Author affiliations: *Central Public Health Laboratory, London, United Kingdom; †Communicable Disease Surveillance Centre, London, United Kingdom

Main Article


Outbreak of infection with O157 VTEC in England and Wales 1995, properties of outbreak strains

No. Month Region/setting (ref)a Cases (HUS/
Fatal) Phage type VT probeb VT2 subtypec
RFLPformula image
PFGE XbaIe Likely transmission of infection
1 Jan Northern/nursing home 7 (0/2) 2 2 2+2c PT2-A PT2-1 Person-to-person
2 May Wessex/Community; hospital 26 (2/0) 2 2 2 PT2-C PT2-2 Foodborne
3 Jul N.W. Thames/Hotel 5 (0/0) 1 1+2 2 PT1-A PT1-1 Foodborne
4 Jul N. Western/Residential home; hospital 3 (1/3) 2 2 2+2c PT2-A PT2-1 Person-to-person
5 Jul Northern/Community (11) 12 (0/1) 2 2 2+2c PT2-A PT2-4 Foodborne
6 Jul Northern/Restaurant 5 (1/0) 2 2 2+2c PT2-A PT2-1a Foodborne
7 Jul East Anglia/HolidayCamp 4 (0/1) 49 2 2+2C PT49-A PT49-1 Foodborne
8 Aug Wales/Day nursery; community 49 (2/0) 2 2 2+2c PT2-B PT2-3 Foodborne, person-to-person
9 Oct W. Midlands/Community (12) 11 (4/0) 2 2 2+2c PT2-Avar PT2-1b Foodborne
10 Oct Various/Community 3 (0/0) RDNCf 1+2 2+2c RDNC-A RDN C-1 Unknown
11 Dec Northern/Day nursery 2 (0/0) 49 2 2+2c PT49-B PT49-2 Unknown

HUS=hemolytic uremic syndrome; VT= Vero cytotoxin; RFLP=restriction fragment length polymorphisms; PFGE=pulsed field gel electrophoresis
aInvestigation of the epidemiology of two outbreaks has been reported previously (11,12)
bDetermined by hybridization with digoxigenin-labeled polynucleotide probes for VT1 and VT2 genes (2,3).
cBased on polymerase chain reaction amplification with a sense primer specific for either the VT2 or VT2c sequence and a degenerate antisense primer that would anneal to known VT2 sequences (14).
dHybridization with a probe comprising digoxigenin-labelled fragments of the VT2-encoding bacteriophage from strain E32511(15). Patterns were designated according to the phage type of the strain and a letter denoting a unique pattern type. The PT2-Avar pattern differed from PT2-A by the possession of a single extra hybridizing fragment.
eProfiles of XbaI digested genomic DNA. Patterns were designated according to the phage type of the strain and differentiated by number. Thus patterns PT2-1, PT2-2, PT2-3, and PT2-4 differed from each other by at least three fragment positions. Where there were single unique band differences from PT2-1 these were designated PT2-1a, etc.
fThe designation RDNC indicates that the strain reacts with the typing phages but does not conform to a currently defined pattern.

Main Article