[Escherichia coli O157:H7 strains carrying Shiga toxin 2 variant slt2vha were isolated from Xuzhou City of Jiangsu Province].
OBJECTIVE
To monitor the changes of predominant Shiga toxin types of Escherichia coli O157:H7 in Xuzhou City, Jiangsu Province.


METHODS
PCR typing with slt2-specific primer pairs (slt2cslt2, slt2v1slt2v2), hybridization of chromosome DNA digested by PstI, and DNA sequencing of PCR products. with slt2-specific primer pairs (slt2cslt2d; slt2eslt2f) were conducted on 14 strains of E. coli isolated from diarrhea patients and dung beetles in 1999 and 2000.


RESULTS
The 5 strains of E. coli isolated from diarrhea patients in 1999 carried slt1 and slt2. The 1 strains of E. coli O157:H7 isolated from diarrhea patients and the 5 strains isolated from dung beetles in 2000 only carried slt2vha, a variance of Shiga toxin 2.


CONCLUSIONS
The predominant Shiga toxin types of E. coli O157:H7 in Xuzhou changed 1999 - 2000, which may be related to the changes of epidemiological features of E. coli O157:H7 infection in Xuzhou. A genotyping method based on restriction fragment length polymorphism (RFLP) analysis of a B-subunit-encoding DNA fragment obtained by PCR described in this study is a useful tool to identify slt2 gene and slt2 variant gene in epidemiological studies with O157:H7 strains.
Zheng
Han
H
Department of Diarrhea Disease, Institute of Communicable Diseases Prevention and Control, Chinese Center for Disease Control and Prevention, Chinese Academy of Preventive Medicine, Beijing 102206, China.
Pan
Bo
B
Jing
Huai-qi
HQ
Yang
Jin-chuan
JC
Zhao
Guang-fa
GF
Li
Hong-wei
HW
Xu
Jian-guo
JG
D015139:Blotting, Southern; D019453:Escherichia coli O157 / Q000472:pathogenicity*; D005838:Genotype; D016133:Polymerase Chain Reaction; D022641:Shiga Toxin 2 / Q000145:classification* / Q000235:genetics
D022641:Shiga Toxin 2