Non-O1/non-O139 V. cholerae strains are highly heterogeneous with considerable serological diversity and vary in virulence properties. The presence of virulence genes amongst some environmental strains is significant, and environmental strains constitute a reservoir of potential pathogenic strains to human diarrhoeal infections [18–21]. Some non-O1/non-O139 strains carry key virulence genes, such as cholera toxin (CT) and toxin co-regulated pili (TCP), which are usually carried by epidemic strains [22]. Some may also carry other virulence factors such as the repeat-like toxin (RtxA) – a cytotoxin

and the heat-stable enterotoxin HKI 272 (NAG-ST) [4, 18, 22–26]. A novel type III secretion system (T3SS) was found in some non-O1/non-O139 strains and appears to be an important virulence factor [27–29]. The T3SS translocates a number of T3SS effectors into the host cell which interfere with host cell signalling [27, 28]. Shin et al.[29] showed that T3SS is an essential virulence factor for the non-O1/non-O139 strain AM-19226. In this study, 40 non-O1/non-O139 V. cholerae

isolates IWP-2 from hospitalised diarrhoeal patients in Zhejiang Province, China were analysed using multilocus sequence typing (MLST) and AZD6738 purchase pulsed-field gel electrophoresis (PFGE) to determine their overall genetic relatedness. The presence of key virulence genes including enterotoxins, TCP and T3SS was also analysed. Results and discussion Isolation of non-O1/non-O139 V. cholerae

isolates from diarrhoeal patients in Zhejiang, China A total of 40 non-O1/non-O139 V. cholerae isolates was retrieved from different cities in Zhejiang Province, China, over a period of six years from 2005 to 2011 (Figure 1, Table 1). Nine isolates were from sporadic cases from seven cities, while 22 isolates were obtained from three outbreaks Docetaxel in three different cities: outbreak A in Ningbo in 2005, outbreak B in Lishui in 2006 and outbreak C in Quzhou in 2011. The three outbreaks were notified as food poisoning events and were investigated. Outbreak A involved 20 cases with symptoms ranging from cholera-like diarrhoea to mild diarrhoea and was initially suspected to be a cholera outbreak. Non-O1/non-O139 V. cholerae was isolated from nine patients. The outbreak occurred in a factory canteen and the food source of the outbreak could not be identified. Outbreak B involved eight cases, all having cholera-like symptoms. Non-O1/non-O139 V. cholerae was isolated from all but one patient. The source of the outbreak was traced to cross contamination of a cold dish from raw cuttlefish. Outbreak C occurred in a family function involving 12 cases with non-O1/non-O139 V. cholerae isolated from nine cases. The source of the outbreak was shrimp. Figure 1 Geographical map of Zhejiang Province, China. Cities are demarcated with dark solid lines.