scholarly journals Genetic Diversity of Toxigenic and Nontoxigenic Vibrio cholerae Serogroups O1 and O139 Revealed by Array-Based Comparative Genomic Hybridization

2007 ◽  
Vol 189 (13) ◽  
pp. 4837-4849 ◽  
Author(s):  
Bo Pang ◽  
Meiying Yan ◽  
Zhigang Cui ◽  
Xiaofen Ye ◽  
Baowei Diao ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Clonal Selection ◽  
Gene Clusters ◽  
Small Chromosome ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Pathogenic Potential ◽  
Genomic Microarray ◽  
Ctx Prophage ◽  
El Tor

ABSTRACT Toxigenic serogroups O1 and O139 of Vibrio cholerae may cause cholera epidemics or pandemics. Nontoxigenic strains within these serogroups also exist in the environment, and also some may cause sporadic cases of disease. Herein, we investigate the genomic diversity among toxigenic and nontoxigenic O1 and O139 strains by comparative genomic microarray hybridization with the genome of El Tor strain N16961 as a base. Conservation of the toxigenic O1 El Tor and O139 strains is found as previously reported, whereas accumulation of genome changes was documented in toxigenic El Tor strains isolated within the 40 years of the seventh pandemic. High phylogenetic diversity in nontoxigenic O1 and O139 strains is observed, and most of the genes absent from nontoxigenic strains are clustered together in the N16961 genome. By comparing these toxigenic and nontoxigenic strains, we observed that the small chromosome of V. cholerae is quite conservative and stable, outside of the superintegron region. In contrast to the general stability of the genome, the superintegron demonstrates pronounced divergence among toxigenic and nontoxigenic strains. Additionally, sequence variation in virulence-related genes is found in nontoxigenic El Tor strains, and we speculate that these intermediate strains may have pathogenic potential should they acquire CTX prophage alleles and other gene clusters. This genome-wide comparison of toxigenic and nontoxigenic V. cholerae strains may promote understanding of clonal differentiation of V. cholerae and contribute to an understanding of the origins and clonal selection of epidemic strains.

Classical RS1 and environmental RS1 elements in Vibrio cholerae O1 El Tor strains harbouring a tandem repeat of CTX prophage: revisiting Mozambique in 2005

2010 ◽  
Vol 59 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Seon Young Choi ◽  
Je Hee Lee ◽  
Eun Jin Kim ◽  
Hye Ri Lee ◽  
Yoon-Seong Jeon ◽  
...  
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Tandem Repeat ◽  
Small Chromosome ◽  
Classical Type ◽  
Large Chromosome ◽  
New Type ◽  
Vibrio Cholerae O1 ◽  
Ctx Prophage ◽  
El Tor

Currently, Vibrio cholerae O1 serogroup biotype El Tor strains producing classical type cholera toxin (altered strains or El Tor variants) are prevalent in Asia and in Mozambique. Mozambican strains collected in 2004 contained a tandem repeat of CTX prophage on the small chromosome and each CTX prophage harboured the classical rstR and classical ctxB. We found that the majority of the strains collected in 2005 in Mozambique contained extra elements on the large chromosome in addition to the tandem repeat of CTX prophage on the small chromosome. New type RS1 elements RS1cla and RS1env, and a CTXenv with rstR env and the classical ctxB were identified on the large chromosome of the Mozambican isolates collected in 2005.

scholarly journals Genetic organization of pre-CTX and CTX prophages in the genome of an environmental Vibrio cholerae non-O1, non-O139 strain

Microbiology ◽  
2006 ◽  
Vol 152 (12) ◽  
pp. 3633-3641 ◽  
Author(s):  
Diganta Maiti ◽  
Bhabatosh Das ◽  
Arjun Saha ◽  
Ranjan K. Nandy ◽  
G. Balakrish Nair ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Genetic Locus ◽  
Single Copy ◽  
Small Chromosome ◽  
Large Chromosome ◽  
Critical Determinant ◽  
Multiple Copies ◽  
New Type ◽  
Ctx Prophage ◽  
El Tor

The cholera toxin (CT) is a critical determinant of the virulence of epidemic Vibrio cholerae strains. The ctxAB operon encoding CT is part of the genome of a filamentous bacteriophage CTXΦ, which may integrate as a single copy or as multiple copies in the genome of V. cholerae. The CTXΦ genome is composed of RS2 (2.4 kb) and core (4.5 kb) regions. In the present study extensive genetic mapping analyses indicated that two copies of tandemly arrayed CTX prophages are integrated in the small chromosome of an environmental V. cholerae strain, VCE232, belonging to serogroup O4. Further mapping revealed that the integration of prophages has occurred in the same genetic locus of the small chromosome of VCE232 as that of V. cholerae O1 biotype El Tor strains. Interestingly, a new type of RS2-like element 3.5 kb in size was found in the CTX prophage genome in the small chromosome of VCE232. Cloning followed by sequencing of the new RS2-like element of VCE232 revealed the presence of three ORFs, which probably encode highly divergent types of phage regulatory proteins. Furthermore, the strain VCE232 also harbours two copies of a tandemly arranged CTX prophage devoid of the ctxAB genes, called pre-CTX prophage, in its large chromosome. The presence of multiple copies of diverse CTX prophages in both the chromosomes of VCE232 suggests that toxigenic environmental V. cholerae non-O1, non-O139 strains could play a role in the emergence of new epidemic clones.

scholarly journals Vibrio cholerae O1 clinical strains isolated in 1992 in Kolkata with progenitor traits of the 2004 Mozambique variant

2009 ◽  
Vol 58 (2) ◽  
pp. 239-247 ◽  
Author(s):  
Souvik Chatterjee ◽  
Tapas Patra ◽  
Kausik Ghosh ◽  
Amit Raychoudhuri ◽  
Gururaja P. Pazhani ◽  
...  
Keyword(s):  
Retrospective Analysis ◽  
Vibrio Cholerae ◽  
Polymyxin B ◽  
Small Chromosome ◽  
Phenotypic Traits ◽  
Clinical Strains ◽  
Vibrio Cholerae O1 ◽  
Ctx Prophage ◽  
El Tor ◽  
Clinical Cases

Retrospective analysis led to the detection of two Vibrio cholerae variant O1 strains (VC51 and VC53), which were isolated in 1992 in Kolkata from clinical cases, with identical traits to 2004 Mozambique variant O1 strains. The Mozambique O1 strains that caused a huge outbreak in 2004 have been shown to have phenotypic traits of both classical and El Tor biotypes, and thereby have been reported as variant. Our study demonstrated that two O1 strains isolated in Kolkata during 1992 were of the El Tor background as evidenced by polymyxin B (50 U ml−1) resistance, positivity in Voges–Proskauer reactions and sensitivity to biotype-specific vibrio phages. With the features of classical CTX prophage, localization in the small chromosome, and an absence of RS1 and pTLC, both Mozambique and Kolkata strains appeared to be identical. Furthermore, two Kolkata strains exhibited an identical ribotype to that of the Mozambique variant, displaying ribotype pattern RI that had been assigned to Kolkata V. cholerae O1 strains isolated on or before 1992. NotI pulsotype analysis indicated that these 1992 Kolkata strains along with the Mozambique variant O1 belonged to very closely related clones. Considering the chronological events, and the typical identity at the phenotypic and the genotypic level between the two O1 strains isolated during 1992 from Kolkata and during 2004 from Mozambique, we propose that some of the 1992 Kolkata O1 strains might have acted as progenitors for Mozambique variant O1 strains.

scholarly journals Pathogenic Potential of Environmental Vibrio cholerae Strains Carrying Genetic Variants of the Toxin-Coregulated Pilus Pathogenicity Island

2003 ◽  
Vol 71 (2) ◽  
pp. 1020-1025 ◽  
Author(s):  
Shah M. Faruque ◽  
M. Kamruzzaman ◽  
Ismail M. Meraj ◽  
Nityananda Chowdhury ◽  
G. Balakrish Nair ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Genetic Variants ◽  
Pathogenicity Island ◽  
Biologically Active ◽  
Pathogenic Potential ◽  
Origin And Evolution ◽  
Colonization Factor ◽  
Evolution Of Virulence ◽  
Toxin Coregulated Pilus ◽  
El Tor

ABSTRACT The major virulence factors of toxigenic Vibrio cholerae are cholera toxin (CT), which is encoded by a lysogenic bacteriophage (CTXΦ), and toxin-coregulated pilus (TCP), an essential colonization factor which is also the receptor for CTXΦ. The genes for the biosynthesis of TCP are part of a larger genetic element known as the TCP pathogenicity island. To assess their pathogenic potential, we analyzed environmental strains of V. cholerae carrying genetic variants of the TCP pathogenicity island for colonization of infant mice, susceptibility to CTXΦ, and diarrheagenicity in adult rabbits. Analysis of 14 environmental strains, including 3 strains carrying a new allele of the tcpA gene, 9 strains carrying a new allele of the toxT gene, and 2 strains carrying conventional tcpA and toxT genes, showed that all strains colonized infant mice with various efficiencies in competition with a control El Tor biotype strain of V. cholerae O1. Five of the 14 strains were susceptible to CTXΦ, and these transductants produced CT and caused diarrhea in adult rabbits. These results suggested that the new alleles of the tcpA and toxT genes found in environmental strains of V. cholerae encode biologically active gene products. Detection of functional homologs of the TCP island genes in environmental strains may have implications for understanding the origin and evolution of virulence genes of V. cholerae.

Comparative genomic analysis of two isolates of Vibrio cholerae O1 Ogawa El Tor isolated during outbreak in Mariupol in 2011

2016 ◽  
Vol 44 ◽  
pp. 471-478 ◽  
Author(s):  
Konstantin V. Kuleshov ◽  
Anna Kostikova ◽  
Sergey V. Pisarenko ◽  
Dmitry A. Kovalev ◽  
Sergey N. Tikhonov ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic ◽  
Vibrio Cholerae O1 ◽  
El Tor

scholarly journals Molecular Analysis of Antibiotic Resistance Gene Clusters in Vibrio cholerae O139 and O1 SXT Constins

2001 ◽  
Vol 45 (11) ◽  
pp. 2991-3000 ◽  
Author(s):  
Bianca Hochhut ◽  
Yasmin Lotfi ◽  
Didier Mazel ◽  
Shah M. Faruque ◽  
Roger Woodgate ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Vibrio Cholerae ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Dna Sequences ◽  
Antibiotic Resistance Gene ◽  
Antibiotic Resistance Genes ◽  
Gene Clusters ◽  
Vibrio Cholerae O139 ◽  
El Tor

ABSTRACT Many recent Asian clinical Vibrio cholerae E1 Tor O1 and O139 isolates are resistant to the antibiotics sulfamethoxazole (Su), trimethoprim (Tm), chloramphenicol (Cm), and streptomycin (Sm). The corresponding resistance genes are located on large conjugative elements (SXT constins) that are integrated into prfC on the V. cholerae chromosome. We determined the DNA sequences of the antibiotic resistance genes in the SXT constin in MO10, an O139 isolate. In SXTMO10, these genes are clustered within a composite transposon-like structure found near the element's 5′ end. The genes conferring resistance to Cm (floR), Su (sulII), and Sm (strA and strB) correspond to previously described genes, whereas the gene conferring resistance to Tm, designated dfr18, is novel. In some other O139 isolates the antibiotic resistance gene cluster was found to be deleted from the SXT-related constin. The El Tor O1 SXT constin, SXTET, does not contain the same resistance genes as SXTMO10. In this constin, the Tm resistance determinant was located nearly 70 kbp away from the other resistance genes and found in a novel type of integron that constitutes a fourth class of resistance integrons. These studies indicate that there is considerable flux in the antibiotic resistance genes found in the SXT family of constins and point to a model for the evolution of these related mobile elements.

scholarly journals Genomic Diversity ofLactobacillus salivarius

2010 ◽  
Vol 77 (3) ◽  
pp. 954-965 ◽  
Author(s):  
Emma J. Raftis ◽  
Elisa Salvetti ◽  
Sandra Torriani ◽  
Giovanna E. Felis ◽  
Paul W. O'Toole
Keyword(s):  
Hot Spots ◽  
Gene Clusters ◽  
Genomic Variation ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Phenotypic Traits ◽  
Lactobacillus Salivarius ◽  
Genome Content ◽  
High Level ◽  
Selection Of

ABSTRACTStrains ofLactobacillus salivariusare increasingly employed as probiotic agents for humans or animals. Despite the diversity of environmental sources from which they have been isolated, the genomic diversity ofL. salivariushas been poorly characterized, and the implications of this diversity for strain selection have not been examined. To tackle this, we applied comparative genomic hybridization (CGH) and multilocus sequence typing (MLST) to 33 strains derived from humans, animals, or food. The CGH, based on total genome content, including small plasmids, identified 18 major regions of genomic variation, or hot spots for variation. Three major divisions were thus identified, with only a subset of the human isolates constituting an ecologically discernible group. Omission of the small plasmids from the CGH or analysis by MLST provided broadly concordant fine divisions and separated human-derived and animal-derived strains more clearly. The two gene clusters for exopolysaccharide (EPS) biosynthesis corresponded to regions of significant genomic diversity. The CGH-based groupings of these regions did not correlate with levels of production of bound or released EPS. Furthermore, EPS production was significantly modulated by available carbohydrate. In addition to proving difficult to predict from the gene content, EPS production levels correlated inversely with production of biofilms, a trait considered desirable in probiotic commensals.L. salivariusdisplays a high level of genomic diversity, and while selection ofL. salivariusstrains for probiotic use can be informed by CGH or MLST, it also requires pragmatic experimental validation of desired phenotypic traits.

scholarly journals RS1 Satellite Phage Promotes Diversity of Toxigenic Vibrio cholerae by Driving CTX Prophage Loss and Elimination of Lysogenic Immunity

2014 ◽  
Vol 82 (9) ◽  
pp. 3636-3643 ◽  
Author(s):  
M. Kamruzzaman ◽  
William Paul Robins ◽  
S. M. Nayeemul Bari ◽  
Shamsun Nahar ◽  
John J. Mekalanos ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Sub Saharan Africa ◽  
Host Cells ◽  
Adult Rabbit ◽  
Content Type ◽  
Rabbit Intestine ◽  
Sub Saharan ◽  
Toxigenic Strains ◽  
Ctx Prophage ◽  
El Tor

ABSTRACTIn El Tor biotype strains of toxigenicVibrio cholerae, the CTXϕ prophage often resides adjacent to a chromosomally integrated satellite phage genome, RS1, which produces RS1ϕ particles by using CTX prophage-encoded morphogenesis proteins. RS1 encodes RstC, an antirepressor against the CTXϕ repressor RstR, which cooperates with the host-encoded LexA protein to maintain CTXϕ lysogeny. We found that superinfection of toxigenic El Tor strains with RS1ϕ, followed by inoculation of the transductants into the adult rabbit intestine, caused elimination of the resident CTX prophage-producing nontoxigenic derivatives at a high frequency. Further studies usingrecAdeletion mutants and a clonedrstCgene showed that the excision event wasrecAdependent and that introduction of additional copies of the clonedrstCgene instead of infection with RS1ϕ was sufficient to enhance CTXϕ elimination. Our data suggest that once it is excised from the chromosome, the elimination of CTX prophage from host cells is driven by the inability to reestablish CTXϕ lysogeny while RstC is overexpressed. However, with eventual loss of the additional copies ofrstC, the nontoxigenic derivatives can act as precursors of new toxigenic strains by acquiring the CTX prophage either through reinfection with CTXϕ or by chitin-induced transformation. These results provide new insights into the role of RS1ϕ inV. choleraeevolution and the emergence of highly pathogenic clones, such as the variant strains associated with recent devastating epidemics of cholera in Asia, sub-Saharan Africa, and Haiti.

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