Characterization of Shiga toxin-producing Escherichia coli isolated from healthy pigs in China

BMC Microbiology

Yanwen Xiong⁶  Jianguo Xu⁶  Kai Liu³  Hui Sun³  Yan Wang³  Bo Yu³  Dong Jin³  Shaobo Ji³  Xuemei Bai³  Xuejiao Yuan³  Changyou Shi⁴  Tao Wang²  Huamao Du¹  Ruiting Lan⁵  Ailan Zhao³  Xiangning Bai³  Qiong Meng⁶ 

[1] Biochemical and Molecular Biological Department, School of Biotechnology, Southwest University, Chongqing, China;Department of Microbiology, School of Basic Medical Sciences, Guiyang Medical University, Guiyang, China;State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China;Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China;School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia;Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China

关键词: Swine;    Pulsed-field gel electrophoresis;    Antibiotic resistance;    Putative virulence genes;    Adhesin genes;    Multilocus sequence typing;    Shiga toxin;    Shiga toxin-producing Escherichia coli (STEC);   

Others  :  1142188
DOI  :  10.1186/1471-2180-14-5

 received in 2013-06-29, accepted in 2014-01-02,  发布年份 2014

【 摘 要 】

Background

Shiga toxin-producing Escherichia coli (STEC) is recognized as an important human diarrheal pathogen. Swine plays an important role as a carrier of this pathogen. In this study we determined the prevalence and characteristics of STEC from healthy swine collected between May 2011 and August 2012 from 3 cities/provinces in China.

Results

A total of 1003 samples, including 326 fecal, 351 small intestinal contents and 326 colon contents samples, was analyzed. Two hundred and fifty five samples were stx-positive by PCR and 93 STEC isolates were recovered from 62 stx-positive samples. Twelve O serogroups and 19 O:H serotypes including 6 serotypes (O100:H20/[H20], O143:H38/[H38], O87:H10, O172:H30/[H30], O159:H16, O9:H30/[H30]) rarely found in swine and ruminants were identified. All 93 STEC isolates harbored stx₂ only, all of which were stx_2e subtype including 1 isolate being a new variant of stx_2e. 53.76%, 15.05% and 2.15% STEC isolates carried astA, hlyA and ehxA respectively. Four STEC isolates harbored the high-pathogenicity island. Of the 15 adherence-associated genes tested, 13 (eae, efa1, iha, lpfA_O113, lpfA_O157/OI-154, lpfA_O157/OI-141, toxB, saa, F4, F5, F6, F17 or F41) were all absent while 2 (paa and F18) were present in 7 and 4 STEC isolates respectively. The majority of the isolates were resistant to tetracycline (79.57%), nalidixic acid (78.49%), trimethoprim-sulfamethoxazole (73.12%) and kanamycin (55.91%). The STEC isolates were divided into 63 pulsed-field gel electrophoresis patterns and 21 sequence types (STs). Isolates of the same STs generally showed the same or similar drug resistance patterns. A higher proportion of STEC isolates from Chongqing showed multidrug resistance with one ST (ST3628) resistant to 14 antimicrobials.

Conclusions

Our results indicate that swine is a significant reservoir of STEC strains in China. Based on comparison by serotypes and sequence types with human strains and presence of virulence genes, the swine STEC may have a low potential to cause human disease.

【 授权许可】

   
2014 Meng et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

Figure 3.

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