Comparative genomics for non-O1/O139 Vibrio cholerae isolates recovered from the Yangtze River Estuary versus V. cholerae representative isolates from serogroup O1

Abstract

Vibrio cholerae, which is autochthonous to estuaries worldwide, can cause human cholera that is still pandemic in developing countries. A number of V. cholerae isolates of clinical and environmental origin worldwide have been subjected to genome sequencing to address their phylogenesis and bacterial pathogenesis, however, little genome information is available for V. cholerae isolates derived from estuaries, particularly in China. In this study, we determined the complete genome sequence of V. cholerae CHN108B (non-O1/O139 serogroup) isolated from the Yangtze River Estuary, China and performed comparative genome analysis between CHN108B and other eight representative V. cholerae isolates. The 4,168,545-bp V. cholerae CHN108B genome (47.2% G+C) consists of two circular chromosomes with 3,691 predicted protein-encoding genes. It has 110 strain-specific genes, the highest number among the eight representative V. cholerae whole genomes from serogroup O1: there are seven clinical isolates linked to cholera pandemics (1937-2010) and one environmental isolate from Brazil. Various mobile genetic elements (such as insertion sequences, prophages, integrative and conjugative elements, and superintegrons) were identified in the nine V. cholerae genomes of clinical and environmental origin, indicating that the bacterium undergoes extensive genetic recombination via lateral gene transfer. Comparative genomics also revealed different virulence and antimicrobial resistance gene patterns among the V. cholerae isolates, suggesting some potential virulence factors and the rising development of resistance among pathogenic V. cholerae. Additionally, draft genome sequences of multiple V. cholerae isolates recovered from the Yangtze River Estuary were also determined, and comparative genomics revealed many genes involved in specific metabolism pathways, which are likely shaped by the unique estuary environment. These results provide additional evidence of V. cholerae genome plasticity and will facilitate better understanding of the genome evolution and pathogenesis of this severe water-borne pathogen worldwide.

The Impact of Water Intrusion on Pathogenic Vibrio Species to Inland Brackish Waters of China

“…For V. cholerae, three virulence profiles (RTX + hlyA, RTX + hlyA + VSP-II, and RTX + hlyA + VSP-II + VSP-I) were found over the entire study period. This finding is consistent with the observation made by Gong et al [37], who reported a diverse set of genes among non-O1/O139 strains from the Yangtze River estuary. The cholera toxin (CT) and toxin coregulated pilus (TCP), which are two major virulence factors of the toxigenic V. cholerae serotypes O1 and O139, were both absent in two rivers from 2018-2019.…”

Simple Visualized Detection Method of Virulence-Associated Genes of Vibrio cholerae by Loop-Mediated Isothermal Amplification

“…High occurrence of the hapA gene was also detected in the presence of V. cholerae strains isolated from the fish intestines (Xu et al, 2019), which may be related to its function involved in V. cholerae interaction with aquatic hosts (Halpern et al, 2003). In contrast, the mshA gene was absent from the fish intestinal samples, and low percentage was present in the 52 V. cholerae strains tested in this study, suggesting missing or truncation of the mshA gene in the bacterium, although the MSHA gene cluster is reported to exist and aid bacterial association with aquatic plankton to support environmental adaptation in many non-O1/O139 strains (Chiavelli et al, 2001;Moorthy and Watnick, 2004;Gong et al, 2019). The finding in this study, coupled with the previous research enhanced need for regular monitoring of V. cholerae contamination in these aquatic products for ensuring food safety.…”

“…V. cholerae produces at least three morphologically distinct types of pili (Hall et al, 1988), including the TCP, mannose-sensitive hemagglutination (MSHA) pilus (Chiavelli et al, 2001;Moorthy and Watnick, 2004), and Type IV-A pilus (Fullner and Mekalanos, 1999;Aagesen and Hase, 2012), which all play important roles in the adaptability and pathogenicity of the bacterium. The mshBACD gene cluster is responsible for the structure of MSHA, which is reported to act not only as a receptor of a widespread filamentous bacteriophage facilitating transfer of virulence genes in V. cholerae O139 strain (Jouravleva et al, 1998), but also aiding bacterial association with aquatic plankton to support environmental adaptation in non O1/O139 strains (Chiavelli et al, 2001;Moorthy and Watnick, 2004;Gong et al, 2019). The third type of pilus is essential for the colonization of Vibrio species in the environment and/or host tissues (Fullner and Mekalanos, 1999).…”

Virulence, Resistance, and Genomic Fingerprint Traits ofVibrio choleraeIsolated from 12 Species of Aquatic Products in Shanghai, China

“…13 Previous studies have revealed virulence-associated factors involved in the pathogenicity of V. cholerae, including zonula occludens toxin (zot), accessory cholera enterotoxin (ace), El Tor hemolysin (hlyA), hemagglutinin protease (hapA), RTX toxin (rtxCABD), thermolabile hemolysin (tlh), mannose-sensitive hemagglutination (MSHA; mshA), and putative type IV pilus ( pilA). [14][15][16][17][18] Therefore, continuous detection of the non-O1/ 0139 V. cholerae in aquatic products is also crucial for food safety systems.…”