Volume 3, Number 4—December 1997
Vero Cytotoxin-Producing Escherichia coli O157 Outbreaks in England and Wales, 1995: Phenotypic Methods and Genotypic Subtyping
|Out-break No.||Month||Region/setting (ref)a||Cases (HUS/ Fatal)||Phage type||VT probeb||VT2 subtypec||
|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|
|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.