title: Distribution of virulence-associated genes and genetic relationships in non-O1/O139 Vibrio cholerae aquatic isolates from China.
abstract: Non-O1/O139 Vibrio cholerae is naturally present in aquatic ecosystems and has been linked with cholera-like diarrhea and local outbreaks. The distribution of virulence-associated genes and genetic relationships among aquatic isolates from China are largely unknown. In this study, 295 aquatic isolates of V. cholerae non-O1/O139 serogroups from different regions in China were investigated. Only one isolate was positive for ctxB and harbored a rare genotype; 10 (3.4%) isolates carried several types of rstR sequences, eight of which carried rare types of toxin-coregulated pili (tcpA). Furthermore, 16 (5.4%) isolates carried incomplete (with partial open reading frames [ORFs]) vibrio seventh pandemic island I (VSP-I) or VSP-II clusters, which were further classified as 11 novel types. PCR-based analyses revealed remarkable variations in the distribution of putative virulence genes, including mshA (95.6%), hlyA (95.3%), rtxC (89.8%), rtxA (82.7%), IS1004 (52.9%), chxA (30.2%), SXT (15.3%), type III secretion system (18.0%), and NAG-ST (3.7%) genes. There was no correlation between the prevalence of putative virulence genes and that of CTX prophage or TCP genes, whereas there were correlations among the putative virulence genes. Further multilocus sequence typing (MLST) placed selected isolates (n = 70) into 69 unique sequence types (STs), which were different from those of the toxigenic O1 and O139 counterparts, and each isolate occupied a different position in the MLST tree. The V. cholerae non-O1/O139 aquatic isolates predominant in China have high genotypic diversity; these strains constitute a reservoir of potential virulence genes, which may contribute to evolution of pathogenic isolates.
authors.affiliation: National Institute for Communicable Disease Control and Prevention, China CDC/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Li
authors.affiliation: National Institute for Communicable Disease Control and Prevention, China CDC/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Du
authors.affiliation: CDC of Guangdong Province, Guangzhou, China.
authors.forename: Baisheng
authors.initials: B
authors.lastname: Li
authors.affiliation: CDC of Guangdong Province, Guangzhou, China.
authors.forename: Changwen
authors.initials: C
authors.lastname: Ke
authors.affiliation: CDC of Fujian Province, Fuzhou, China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Chen
authors.affiliation: CDC of Dandong, Dandong, Liaoning Province, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: National Institute for Communicable Disease Control and Prevention, China CDC/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhou
authors.affiliation: National Institute for Communicable Disease Control and Prevention, China CDC/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA.
authors.forename: J Glenn
authors.initials: JG
authors.lastname: Morris
authors.affiliation: National Institute for Communicable Disease Control and Prevention, China CDC/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China wangduochun@icdc.cn kanbiao@icdc.cn.
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
authors.affiliation: National Institute for Communicable Disease Control and Prevention, China CDC/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China wangduochun@icdc.cn kanbiao@icdc.cn.
authors.forename: Duochun
authors.initials: D
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002681:China / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*; D016415:Sequence Alignment; D041242:Vibrio cholerae O139 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D044163:Vibrio cholerae non-O1 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors