Basic Research
Copyright ©The Author(s) 2005. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 7, 2005; 11(37): 5816-5820
Published online Oct 7, 2005. doi: 10.3748/wjg.v11.i37.5816
Enteroaggregative Escherichia coli isolated from Chinese diarrhea patients with high-pathogenicity island ofYersinia is involved in synthesis of siderophore yersiniabactin
Jing Hu, Biao Kan, Zhi-Hua Liu, Shou-Yi Yu
Jing Hu, Shou-Yi Yu, Department of Epidemiology, Southern Medical College, Guangzhou 510515, Guangdong Province, China
Biao Kan, Department of Genetics, Institute of Epidemiology and Microbiology, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Zhi-Hua Liu, Department of Infectious Diseases, Nanfang Hospital, Southern Medical College, Guangzhou 510515, Guangdong Province, China
Author contributions: All authors contributed equally to the work.
Supported by the National Basic Research Program of Ministry of Science and Technology of China, No. G1999054101
Correspondence to: Professor Shou-Yi Yu, Department of Epidemiology, Southern Medical College, Guangzhou 510515, Guangdong Province, China. yushouyi@fimmu.com
Telephone: +86-20-61648313 Fax: +86-20-61648312
Received: January 15, 2005
Revised: February 23, 2005
Accepted: February 28, 2005
Published online: October 7, 2005
Abstract

AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli (EAggEC) isolated from Chinese diarrhea patients.

METHODS: The distribution of 12 HPI genes was investigated by PCR and DNA hybridization in two prototype strains ofEAggEC, EAggEC 17-2, EAggEC O42, and 6 clinical EAggEC isolates from China. The production of siderophore Ybt in HPI-positive strains was detected by reporter gene bioassay to determine the relation between HPI genes and expression of Ybt. Flow cytometry was used to detect fluorescent signal of the reporter strain that could designate production of Ybt.

RESULTS: Seven strains were HPI-positive and one strain was HPI-negative. Six of the seven HPI-positive strains were inserted into asnT-tRNA site. Moreover, seven EAggEC HPI-positive strains revealed enhanced fluorescence signal but the EAggEC HPI-negative strain did not. However, there was a difference in Ybt expression condition and level among these seven EAggEC HPI-positive strains. Although UFT073 strain, the prototype strain of uropathogenic E.coli (UPEC), carried the complete HPI core part, we did not detect the expression of Ybt in it.

CONCLUSION: EAggEC HPI-positive strains can express the Ybt system, but the presence of HPI core part does not mean the functional expression of Ybt.

Keywords: High-pathogenicity island, Enteroaggregative Escherichia coli, Yersiniabactin