Genetic relatedness of selected clinical Vibrio cholerae O139 isolates from the southern coastal area of China over a 20-year period.
Vibrio cholerae O139 emerged as a causative agent of epidemic cholera in 1992 in India and Bangladesh, and was subsequently reported in China in 1993. The genetic relatedness and molecular characteristics of V. cholerae O139 in Guangdong Province, located in the southern coastal area of China, remains undetermined. In this study, we investigated 136 clinical V. cholerae O139 isolates from 1993 to 2013 in Guangdong. By conventional PCR, 123 (90·4%) isolates were positive for ctxB, ace and zot. Sequencing of the positive amplicons indicated 113 (91·7%) isolates possessed the El Tor allele of ctxB (genotype 3); seven carried the classical ctxB type (genotype 1) and three harboured a novel ctxB type (genotype 5). With respect to tcpA, 123 (90·4%) isolates were positive for the El Tor allele. In addition, pulsed-field gel electrophoresis (with NotI digestion) differentiated the isolates into clusters A and B. Cluster A contained seven of the non-toxigenic isolates from 1998 to 2000; another six non-toxigenic isolates (from 1998 and 2007) and all of the toxigenic isolates formed cluster B. Our results suggest that over a 20-year period, the predominant O139 clinical isolates have maintained a relatively tight clonal structure, although some genetic variance and shift has occurred. Our data highlight the persistence of toxigenic V. cholerae O139 in clinical settings in the southern coastal area of China.
Key Laboratory for Repository and Application of Pathogenic Microbiology,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases,Guangdong Provincial Center for Disease Control and Prevention,Guangzhou,China.
B S
BS
Li
School of Public Health and Tropical Medicine,Southern Medical University,Guangzhou,China.
Y
Y
Xiao
State Key Laboratory of Infectious Disease Prevention and Control,National Institute for Communicable Disease Control and Prevention,ChinaCDC,Beijing,China.
D C
DC
Wang
Key Laboratory for Repository and Application of Pathogenic Microbiology,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases,Guangdong Provincial Center for Disease Control and Prevention,Guangzhou,China.
H L
HL
Tan
Key Laboratory for Repository and Application of Pathogenic Microbiology,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases,Guangdong Provincial Center for Disease Control and Prevention,Guangzhou,China.
B X
BX
Ke
Key Laboratory for Repository and Application of Pathogenic Microbiology,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases,Guangdong Provincial Center for Disease Control and Prevention,Guangzhou,China.
D M
DM
He
Key Laboratory for Repository and Application of Pathogenic Microbiology,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases,Guangdong Provincial Center for Disease Control and Prevention,Guangzhou,China.
C W
CW
Ke
Key Laboratory for Repository and Application of Pathogenic Microbiology,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases,Guangdong Provincial Center for Disease Control and Prevention,Guangzhou,China.
Y H
YH
Zhang
D000595:Amino Acid Sequence; D002681:China / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology* / Q000382:microbiology; D002772:Cholera Toxin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D005838:Genotype; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D041242:Vibrio cholerae O139 / Q000235:genetics*
D002772:Cholera Toxin
Bacterial typing; Vibrio cholerae; clinical microbiology; epidemics