Evaluating the use of multilocus variable number tandem repeat analysis of Shiga toxin-producing Escherichia coli O157 as a routine public health tool in England.
Multilocus variable number tandem repeat analysis (MLVA) provides microbiological support for investigations of clusters of cases of infection with Shiga toxin-producing E. coli (STEC) O157. All confirmed STEC O157 isolated in England and submitted to the Gastrointestinal Bacteria Reference Unit (GBRU) during a six month period were typed using MLVA, with the aim of assessing the impact of this approach on epidemiological investigations. Of 539 cases investigated, 341 (76%) had unique (>2 single locus variants) MLVA profiles, 12% of profiles occurred more than once due to known household transmission and 12% of profiles occurred as part of 41 clusters, 21 of which were previously identified through routine public health investigation of cases. The remaining 20 clusters were not previously detected and STEC enhanced surveillance data for associated cases were retrospectively reviewed for epidemiological links including shared exposures, geography and/or time. Additional evidence of a link between cases was found in twelve clusters. Compared to phage typing, the number of sporadic cases was reduced from 69% to 41% and the diversity index for MLVA was 0.996 versus 0.782 for phage typing. Using MLVA generates more data on the spatial and temporal dispersion of cases, better defining the epidemiology of STEC infection than phage typing. The increased detection of clusters through MLVA typing highlights the challenges to health protection practices, providing a forerunner to the advent of whole genome sequencing as a diagnostic tool.
Gastrointestinal Emerging and Zoonotic Infections Department, Health Protection Services, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Lisa
L
Byrne
Gastrointestinal Emerging and Zoonotic Infections Department, Health Protection Services, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Richard
R
Elson
Gastrointestinal Bacteria Reference Unit, Microbiology Services, GBRU, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Timothy J
TJ
Dallman
Gastrointestinal Bacteria Reference Unit, Microbiology Services, GBRU, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Neil
N
Perry
Gastrointestinal Bacteria Reference Unit, Microbiology Services, GBRU, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Philip
P
Ashton
Faculty of Medicine and Health Services, Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
John
J
Wain
Gastrointestinal Emerging and Zoonotic Infections Department, Health Protection Services, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Goutam K
GK
Adak
Gastrointestinal Bacteria Reference Unit, Microbiology Services, GBRU, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Kathie A
KA
Grant
Gastrointestinal Bacteria Reference Unit, Microbiology Services, GBRU, Public Health England, Centre for Infectious Disease Surveillance and Control, London, United Kingdom.
Claire
C
Jenkins
D004739:England; D019453:Escherichia coli O157 / Q000235:genetics* / Q000302:isolation & purification; D008040:Genetic Linkage; D018598:Minisatellite Repeats / Q000235:genetics*; D058885:Multilocus Sequence Typing / Q000379:methods*; D010802:Phylogeny; D011634:Public Health / Q000379:methods*