scholarly journals Comparative analysis of the genome regions associated with virulence in original classic and El Tor Biovars of Vibrio cholerae strains

2014 ◽  
Vol 19 (2) ◽  
pp. 26-33
Author(s):  
T. A. Kul’shan ◽  
N. B. Cheldyshova ◽  
N. P. Guseva ◽  
N. I. Smirnova

The comparative analysis of the genome regions associated with virulence in various V. cholerae strains: classical biovar, as well as typical and genetically altered strains of El Tor biovar was performed with the use of PCR assays and fragment sequencing. V. cholerae classical biovar genome was demonstrated to be more stable in comparison with the same in V. cholerae El Tor biovar. Within the genome of El Tor vibrios there were identified extensive variable regions carrying pathogenicity genes. It was also found that unlike classical cholera vibrios, in the V. cholerae El Tor genome there is absent CRISPR-system limiting horizontal transfer of the genes. The obtained data concerning these structural peculiarities of V. cholerae El Tor genome may be used in the delivery of the new generations of gene-diagnostic preparations and for improvement of molecular-epidemiological monitoring in case of cholera.

2003 ◽  
Vol 71 (6) ◽  
pp. 2993-2999 ◽  
Author(s):  
Shah M. Faruque ◽  
Jun Zhu ◽  
Asadulghani ◽  
M. Kamruzzaman ◽  
John J. Mekalanos

ABSTRACT The major virulence factors of toxigenic Vibrio cholerae are cholera toxin, which is encoded by a lysogenic filamentous bacteriophage (CTXΦ), and toxin-coregulated pilus (TCP), an essential colonization factor that is also the receptor for CTXΦ. The genes involved in the biosynthesis of TCP reside in a pathogenicity island, which has been reported to correspond to the genome of another filamentous phage (designated VPIΦ) and to encode functions necessary for the production of infectious VPIΦ particles. We examined 46 V. cholerae strains having diverse origins and carrying different genetic variants of the TCP island for the production of the VPIΦ and CTXΦ in different culture conditions, including induction of prophages with mitomycin C and UV irradiation. Although 9 of 10 V. cholerae O139 strains and 12 of 15 toxigenic El Tor strains tested produced extracellular CTXΦ, none of the 46 TCP-positive strains produced detectable VPIΦ in repeated assays, which detected as few as 10 particles of a control CTX phage per ml. These results contradict the previous report regarding VPIΦ-mediated horizontal transfer of the TCP genes and suggest that the TCP island is unable to support the production of phage particles. Further studies are necessary to understand the mechanism of horizontal transfer of the TCP island.


Author(s):  
S. P. Zadnova ◽  
T. A. Kul’Shan’ ◽  
N. B. Cheldyshova ◽  
A. A. Kritsky ◽  
N. A. Plekhanov ◽  
...  

Author(s):  
A. A. Kritsky ◽  
N. I. Smirnova ◽  
T. B. Kalyaeva ◽  
N. F. Obrotkina ◽  
I. V. Gracheva ◽  
...  

Objective of the study was to perform a comparative analysis of molecular-genetic properties in non-toxigenic Vibrio cholerae O1 strains biovar El Tor, isolated in the Republic of Kalmykia and on cholera endemic territories and to reveal their phylogenetic relations to toxigenic isolates.Materials and methods. We have carried out bio-information analysis of whole genome sequences of 60 cholera vibrio strains from endemic as regards cholera regions and from Kalmykia. The presence of pathogenicity and endemicity islands in their genomes has been determined. Specifed have been the sequence-types of the examined strains and whole genome SNP-analysis conducted.Results and discussion. Non-toxigenic El Tor vibrios circulating in Kalmykia are clustered into two major genotypes: ctxA–tcpA+VPI-2+VSP– and ctxA–tcpA–VPI-2Δ+VSP–, where VPI-2 Δ+ signifes the presence of deletions of varying length in the genome of this pathogenicity island. Only the latter one is found in regions endemic for cholera. In addition, ctxA– tcpA+VPI-2+VSP+ populations circulate in cholera endemic foci, not found in Kalmykia. 17 sequence-types were identifed among the studied strains (by seven housekeeping gene loci). Phylogenetic analysis performed using SNP-typing demonstrated the absence of close genetic relation between the ctxA–tcpA+VPI-2+VSP– vibrios from Kalmykia and both toxigenic and non-toxigenic vibrios with different composition of pathogenicity and pandemicity islands in the genome. At the same time, genetic proximity of ctxA–tcpA–VPI-2Δ+VSP– cholera vibrios from endemic cholera foci with those isolated in Kalmykia was detected, which may indicate the possibility of their recurrent importation into the territory of Russia. Non-toxigenic V. cholerae strains found in the territory of Kalmykia are characterized by a high genetic diversity. Circulation of the strains with unique sequence-types suggests their potential for long-term persistence on this territory. At the same time, phylogenetic closeness and identity of certain strains with strains from endemic territories can be an evidence of repeated importation.


Author(s):  
S. P. Zadnova ◽  
A. A. Kritsky ◽  
N. A. Plekhanov ◽  
N. B. Cheldyshova ◽  
N. I. Smirnova

2020 ◽  
Vol 56 (9) ◽  
pp. 1055-1069
Author(s):  
N. I. Smirnova ◽  
A. A. Kritsky ◽  
J. V. Alkhova ◽  
E. Yu. Agafonova ◽  
E. Yu. Shchelkanova ◽  
...  

The Lancet ◽  
1979 ◽  
Vol 314 (8134) ◽  
pp. 147-148 ◽  
Author(s):  
K.J. Towner ◽  
N.J. Pearson ◽  
F. O'Grady
Keyword(s):  

2015 ◽  
Vol 205 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Debdutta Bhattacharya ◽  
Shuchismita Dey ◽  
Gururaja Perumal Pazhani ◽  
Thandavarayan Ramamurthy ◽  
Mahantesh V. Parande ◽  
...  

2006 ◽  
Vol 55 (11) ◽  
pp. 1559-1562 ◽  
Author(s):  
G. Balakrish Nair ◽  
Ashrafus Safa ◽  
N. A. Bhuiyan ◽  
Suraia Nusrin ◽  
Denise Murphy ◽  
...  

2012 ◽  
Vol 17 (5) ◽  
pp. 31-35
Author(s):  
V. N. Savelyev ◽  
I. V. Savelyeva ◽  
B. V. Babenyshev ◽  
A. N. Kulichenko

In a comparative perspective studied cholera outbreak in the Caucasus due to typical toxigenic and genetically modified (hybrid) El Tor variant strains have been studied. Revealed features of the genetic structure of the genome, factors and ways of transmission of the causative agent of modern cholera El tor should be considered when improving the program of epidemiological supervision in terms of enhancing antiepidemic and prevention measures in cholera, the causative factor of which are of hybrid variants of Vibrio cholerae El tor.


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