Class I integrons and SXT elements in El Tor strains isolated before and after 1992 Vibrio cholerae O139 outbreak, Calcutta, India.
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ABSTRACT:
SUBMITTER: Amita
PROVIDER: S-EPMC2957977 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Vibrio cholerae O139 is a recently identified non-O1 V. cholerae strain responsible for outbreaks of epidemic cholera in India, Bangladesh, and Thailand in the past 2 years. Other workers have demonstrated the presence of the cholera toxin genetic element in V. cholerae O139, unlike the situation for other non-O1 V. cholerae strains. We sought to compare further this strain with strains of V. cholerae O1, classical and El Tor biotypes, by classic microbiologic methods, Southern blot analysis for restriction fragment length polymorphisms with probes for iron-regulated genes of V. cholerae O1, and comparisons of outer membrane protein profiles. Our results were similar for V. cholerae O139 and the El Tor biotype of V. cholerae O1, with the exception of the constitutive expression in V. cholerae O139 of OmpS, an outer membrane protein that was maltose inducible in comparison strains of V. cholerae O1.
| S-EPMC186314 | biostudies-other
Project description:UNLABELLED:Cholera continues to be a global threat, with high rates of morbidity and mortality. In 2011, a cholera outbreak occurred in Palawan, Philippines, affecting more than 500 people, and 20 individuals died. Vibrio cholerae O1 was confirmed as the etiological agent. Source attribution is critical in cholera outbreaks for proper management of the disease, as well as to control spread. In this study, three V. cholerae O1 isolates from a Philippines cholera outbreak were sequenced and their genomes analyzed to determine phylogenetic relatedness to V. cholerae O1 isolates from recent outbreaks of cholera elsewhere. The Philippines V. cholerae O1 isolates were determined to be V. cholerae O1 hybrid El Tor belonging to the seventh-pandemic clade. They clustered tightly, forming a monophyletic clade closely related to V. cholerae O1 hybrid El Tor from Asia and Africa. The isolates possess a unique multilocus variable-number tandem repeat analysis (MLVA) genotype (12-7-9-18-25 and 12-7-10-14-21) and lack SXT. In addition, they possess a novel 15-kb genomic island (GI-119) containing a predicted type I restriction-modification system. The CTX?-RS1 array of the Philippines isolates was similar to that of V. cholerae O1 MG116926, a hybrid El Tor strain isolated in Bangladesh in 1991. Overall, the data indicate that the Philippines V. cholerae O1 isolates are unique, differing from recent V. cholerae O1 isolates from Asia, Africa, and Haiti. Furthermore, the results of this study support the hypothesis that the Philippines isolates of V. cholerae O1 are indigenous and exist locally in the aquatic ecosystem of the Philippines. IMPORTANCE:Genetic characterization and phylogenomics analysis of outbreak strains have proven to be critical for probing clonal relatedness to strains isolated in different geographical regions and over time. Recently, extensive genetic analyses of V. cholerae O1 strains isolated in different countries have been done. However, genome sequences of V. cholerae O1 isolates from the Philippines have not been available for epidemiological investigation. In this study, molecular typing and phylogenetic analysis of Vibrio cholerae isolated from both clinical and environmental samples in 2011 confirmed unique genetic features of the Philippines isolates, which are helpful to understand the global epidemiology of cholera.
| S-EPMC4453562 | biostudies-literature
Project description:Vibrio cholerae O1 El Tor biotype strains are responsible for three multiyear epidemics of cholera in China during the seventh ongoing pandemic. The presence of the integrative conjugative element SXT is strongly correlated with resistance to nalidixic acid, tetracycline, and trimethoprim-sulfamethoxazole in these strains. Here, we sequenced the conserved genes of the SXT element, including eex, setR, and int, from 59 V. cholerae O1 El Tor strains and extracted and assembled the intact SXT sequences from the 11 genome sequenced strains. These elements had characteristics distinct from those of previously reported integrative conjugative elements (ICEs). They could be clearly divided into two types based on the clustering of conserved genes and gene structures of the elements, showing their possibly independent derivation and evolution. These two types were present before and after 2005, respectively, demonstrating the type substitution that occurred in 2005. Four to six antibiotic-resistant genes were found on the SXT elements, including genes resistant to tetracycline, trimethoprim-sulfamethoxazole, and multiple drugs. In summary, our findings demonstrated the roles of the SXT element in the emergence of multidrug resistance in epidemic O1 El Tor V. cholerae strains in China.
| S-EPMC4783696 | biostudies-literature
Project description: Not available
| S-EPMC5088018 | biostudies-literature
Project description:Forty-four Vibrio cholerae isolates collected over a 7-month period in Chennai, India in 2004 were characterized for gene traits, antimicrobial susceptibility and genomic fingerprints. All 44 isolates were identified as O1 El Tor Ogawa, positive for various toxigenic and pathogenic genes viz. ace, ctxB, hlyA, ompU, ompW, rfbO1, rtx, tcpA, toxR and zot. Nucleotide sequencing revealed the presence of cholera toxin B of classical biotype in all the El Tor isolates, suggesting infection of isolates by classical CTXPhi. Antibiogram analysis showed a broad-spectrum antibiotic resistance that was also confirmed by the presence of resistant genes in the genomes. All isolates contained a class 1 integron and an SXT constin. However, isolates were sensitive to chloramphenicol and tested negative for the chloramphenicol resistant gene suggesting a deletion in SXT constin. Fingerprinting analysis of isolates by ERIC- and Box PCR revealed similar DNA patterns indicating the clonal dissemination of a single predominant V. cholerae O1 strain throughout the 2004 outbreak in Chennai. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11274-009-0171-7) contains supplementary material, which is available to authorized users.
| S-EPMC2872801 | biostudies-literature
Project description:CTXphi is a lysogenic, filamentous bacteriophage. Its genome includes the genes encoding cholera toxin (ctxAB), one of the principal virulence factors of Vibrio cholerae; consequently, nonpathogenic strains of V. cholerae can be converted into toxigenic strains by CTXphi infection. O139 Calcutta strains of V. cholerae, which were linked to cholera outbreaks in Calcutta, India, in 1996, are novel pathogenic strains that carry two distinct CTX prophages integrated in tandem: CTX(ET), the prophage previously characterized within El Tor strains, and a new CTX Calcutta prophage (CTX(calc)). We found that the CTX(calc) prophage gives rise to infectious virions; thus, CTX(ET)phi is no longer the only known vector for transmission of ctxAB. The most functionally significant differences between the nucleotide sequences of CTX(calc)phi and CTX(ET)phi are located within the phages' repressor genes (rstR(calc) and rstR(ET), respectively) and their RstR operators. RstR(calc) is a novel, allele-specific repressor that regulates replication of CTX(calc)phi by inhibiting the activity of the rstA(calc) promoter. RstR(calc) has no inhibitory effect upon the classical and El Tor rstA promoters, which are instead regulated by their cognate RstRs. Consequently, production of RstR(calc) renders a CTX(calc) lysogen immune to superinfection by CTX(calc)phi but susceptible (heteroimmune) to infection by CTX(ET)phi. Analysis of the prophage arrays generated by sequentially integrated CTX phages revealed that pathogenic V. cholerae O139 Calcutta probably arose via infection of an O139 CTX(ET)phi lysogen by CTX(calc)phi.
| S-EPMC94144 | biostudies-literature
Project description:The transcriptional factor ToxR initiates a virulence regulatory cascade required for V. cholerae to express critical host colonization factors and cause disease. Genome-wide expression studies suggest that ToxR regulates many genes important for V. cholerae pathogenesis, yet our knowledge of the direct regulon controlled by ToxR is limited to just four genes. Here, we determine ToxR’s genome-wide DNA-binding profile and show that ToxR is a global regulator of both progenitor genome-encoded genes and horizontally acquired islands encoding the majority of V. cholerae’s major virulence factors. Our results suggest that ToxR has gained regulatory control over important acquired elements that not only drive V. cholerae pathogenesis but that also define the major transitions of V. cholerae pandemic lineages. We demonstrate that ToxR shares nearly half its regulon with the histone-like nucleoid structuring protein H-NS, and antagonizes H-NS for control of critical colonization functions. This regulatory interaction is the major role of ToxR in V. cholerae colonization since deletion of H-NS abrogates the need of ToxR in V. cholerae host colonization. By comparing the genome-wide binding profiles of ToxR and other critical virulence regulators, we show that despite similar predicted DNA binding requirements, ToxR is unique in its global control of progenitor-encoded and acquired genes. Our results suggest that, like H-NS, factors in addition to linear DNA sequence drive selection of ToxR binding sites.
2016-03-23 | GSE72473 | GEO
Project description:The transcriptional factor ToxR initiates a virulence regulatory cascade required for V. cholerae to express critical host colonization factors and cause disease. Genome-wide expression studies suggest that ToxR regulates many genes important for V. cholerae pathogenesis, yet our knowledge of the direct regulon controlled by ToxR is limited to just four genes. Here, we determine ToxR’s genome-wide DNA-binding profile and show that ToxR is a global regulator of both progenitor genome-encoded genes and horizontally acquired islands encoding the majority of V. cholerae’s major virulence factors. Our results suggest that ToxR has gained regulatory control over important acquired elements that not only drive V. cholerae pathogenesis but that also define the major transitions of V. cholerae pandemic lineages. We demonstrate that ToxR shares nearly half its regulon with the histone-like nucleoid structuring protein H-NS, and antagonizes H-NS for control of critical colonization functions. This regulatory interaction is the major role of ToxR in V. cholerae colonization since deletion of H-NS abrogates the need of ToxR in V. cholerae host colonization. By comparing the genome-wide binding profiles of ToxR and other critical virulence regulators, we show that despite similar predicted DNA binding requirements, ToxR is unique in its global control of progenitor-encoded and acquired genes. Our results suggest that, like H-NS, factors in addition to linear DNA sequence drive selection of ToxR binding sites.
2016-03-23 | GSE72472 | GEO
Project description:The transcriptional factor ToxR initiates a virulence regulatory cascade required for V. cholerae to express critical host colonization factors and cause disease. Genome-wide expression studies suggest that ToxR regulates many genes important for V. cholerae pathogenesis, yet our knowledge of the direct regulon controlled by ToxR is limited to just four genes. Here, we determine ToxR’s genome-wide DNA-binding profile and show that ToxR is a global regulator of both progenitor genome-encoded genes and horizontally acquired islands encoding the majority of V. cholerae’s major virulence factors. Our results suggest that ToxR has gained regulatory control over important acquired elements that not only drive V. cholerae pathogenesis but that also define the major transitions of V. cholerae pandemic lineages. We demonstrate that ToxR shares nearly half its regulon with the histone-like nucleoid structuring protein H-NS, and antagonizes H-NS for control of critical colonization functions. This regulatory interaction is the major role of ToxR in V. cholerae colonization since deletion of H-NS abrogates the need of ToxR in V. cholerae host colonization. By comparing the genome-wide binding profiles of ToxR and other critical virulence regulators, we show that despite similar predicted DNA binding requirements, ToxR is unique in its global control of progenitor-encoded and acquired genes. Our results suggest that, like H-NS, factors in addition to linear DNA sequence drive selection of ToxR binding sites.
2016-03-23 | GSE72471 | GEO
Project description:Using a combination of ChIP-seq and RNA-seq we show that ToxT regulates expression of the small RNA TarB. TarB modulates the expression level of the transcriptioanl repressor VC0177. VC0177 controls expression of several genes including VC0179.
2012-04-13 | GSE36373 | GEO