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Open Access Highly Accessed Research article

Molecular analysis of non-O1/non-O139 Vibrio cholerae isolated from hospitalised patients in China

Yun Luo1, Julian Ye1, Dazhi Jin1*, Gangqiang Ding1, Zheng Zhang1, Lingling Mei1, Sophie Octavia2 and Ruiting Lan2*

Author Affiliations

1 Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China

2 School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia

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BMC Microbiology 2013, 13:52  doi:10.1186/1471-2180-13-52

Published: 4 March 2013

Abstract

Background

Cholera is still a significant public health issue in developing countries. The aetiological agent is Vibrio cholerae and only two serogroups, O1 and O139, are known to cause pandemic or epidemic cholera. In contrast, non-O1/non-O139 V. cholerae has only been reported to cause sporadic cholera-like illness and localised outbreaks. The aim of this study was to determine the genetic diversity of non-O1/non-O139 V. cholerae isolates from hospitalised diarrhoeal patients in Zhejiang Province, China.

Results

In an active surveillance of enteric pathogens in hospitalised diarrhoeal patients, nine non-O1/non-O139 V. cholerae isolates were identified from 746 diarrhoeal stool samples at a rate of 1.2%. These isolates and an additional 31 isolates from sporadic cases and three outbreaks were analysed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). PFGE divided the isolates into 25 PFGE types while MLST divided them into 15 sequence types (STs). A single ST, ST80, was predominant which persisted over several years in different cities and caused two outbreaks in recent years. Antibiotic resistance varied with the majority of the isolates resistant to sulphamethoxazole/trimethoprim and nearly all isolates either resistant or intermediate to erythromycin and rifampicin. None of the isolates carried the cholera toxin genes or toxin co-regulated pilus genes but the majority carried a type III secretion system as the key virulence factor.

Conclusions

Non-O1/non-O139 V. cholerae is an important contributor to diarrhoeal infections in China. Resistance to commonly used antibiotics limits treatment options. Continuous surveillance of non-O1/non-O139 V. cholerae is important for control and prevention of diarrhoeal infections.

Keywords:
Vibrio cholerae; Non-O1/non-O139 serogroups; Pulsed-field gel electrophoresis; Multilocus sequence typing; Antibiotic resistance; Type III secretion system