Molecular characterization of enterohemorrhagic Escherichia coli O157:H7 isolates dispersed across Japan by pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analysis.
We identified seven distinct subtypes of enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates that were derived from sporadic cases and outbreaks from multiple prefectures in Japan in 2005. A surveillance system utilizing pulsed-field gel electrophoresis (PFGE), PulseNet Japan, was used. Some strains showed indistinguishable PFGE patterns using another restriction enzyme (BlnI or SpeI) in each subtype of EHEC O157:H7 isolates that were routinely subtyped by the XbaI PFGE pattern. In order to examine the genotypic relatedness of these strains, we carried out a multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA). By using the MLVA system, we found that three of seven subtypes of EHEC O157:H7 strains that were isolated from sporadic cases dispersed across multiple prefectures within a few months showed indistinguishable PFGE patterns and identical MLVA types. Strains belonging to the other four subtypes of EHEC O157:H7 in the PFGE analysis were further classified into different clusters of EHEC O157:H7. Therefore, compared to PFGE, MLVA showed greater discriminatory power with respect to analysis of the isolates in this study.
Pei
Yingxin
Y
Department of Epidemiology, Public Health College, Harbin Medical University, Harbin, China.
Terajima
Jun
J
Saito
Yasunori
Y
Suzuki
Reiko
R
Takai
Nobuko
N
Izumiya
Hidemasa
H
Morita-Ishihara
Tomoko
T
Ohnishi
Makoto
M
Miura
Masashi
M
Iyoda
Sunao
S
Mitobe
Jiro
J
Wang
Binyou
B
Watanabe
Haruo
H
D000483:Alleles; D015373:Bacterial Typing Techniques; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D054324:Enterohemorrhagic Escherichia coli / Q000145:classification / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D018598:Minisatellite Repeats