Molecular subtyping of Vibrio cholerae isolates from outbreaks of cholera by pulsed-field gel electrophoresis in Hainan in 2008

Abstract

To analyze the molecular characteristics and genetic correlations of Vibrio cholerae isolates in Hainan in 2008, so as to provide pathogenic proof to diagnose the plague. Seventy six cholera strains were isolated from this cholera epidemic.69 strains were obtained from patients, 7 were isolated from external environment, among which, one was from patient's toilet, one from water sample, three were isolated from fish pond near patient's home, one came from swab of the patient vomit on the ground of health center and one from swab of kitchen knife from Hainan University canteen respectively. With conventional aetiological methods, pulse-field gel electrophoresis was conducted and the patterns of the 76 isolates were analyzed. The PFGE image was analyzed using BioNumerics (Version4.0, Applied Maths BVBA, Belium). Image bands were identified and similarity coefficient was automatically generated. Seventy six strains were isolated from Vibrio cholerae outbreaks in Hainan in 2008.5 PFGE patterns of patient's isolates in June were the same, sharing a similarity coefficient of 100%. 70 PFGE patterns of patients and water in October and November were completely same, the similarity coefficient being 100%. But they were not same as that of June. 1 PFGE pattern of isolate from the sample in Hainan University was different, only sharing a similarity coefficient of 79.7%, which showed no correlation with the outbreak. Different outbreaks of Vibrio cholera occurred in Hainan in 2008. The epidemic in October and November at different counties was one outbreak. The pollution of water in environment was an important factor for outbreak.