Molecular–genetic peculiarities of classical biotype Vibrio cholerae, the etiological agent of the last outbreak Asiatic cholera in Russia

Smirnova, N. I.; Cheldyshova, N. B.; Zadnova, S. P.; Кутырев, Владимир

doi:10.1016/j.micpath.2003.10.004

Cited by 9 publications

(4 citation statements)

References 31 publications

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“…This report clearly suggests that in high protease producers, in which EDTA can inhibit activity, the protease could be hemagglutinin protease; in strains in which HAP is not secreted, the serine protease could be the major protease. The 59-kDa serine protease could be the major protease in classical strains like 569 B. Molecular genetic analysis of classical biotype V. cholerae strains that caused cholera outbreaks in 1942 in Russia showed that these strains contain the gene hapA, demonstrated by PCR, but produce no soluble HAP [30]. It would be interesting to study the presence and role of the 59-kDa serine protease in such classical V. cholerae O1 strains.…”

Section: Discussionmentioning

confidence: 99%

Studies on a Novel Serine Protease of a ΔhapAΔprtV Vibrio cholerae O1 Strain and Its Role in Hemorrhagic Response in the Rabbit Ileal Loop Model

et al. 2010

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BackgroundTwo well-characterized proteases secreted by Vibrio cholerae O1 strains are hemagglutinin protease (HAP) and V. cholerae protease (PrtV). The hapA and prtV knock out mutant, V. cholerae O1 strain CHA6.8ΔprtV, still retains residual protease activity. We initiated this study to characterize the protease present in CHA6.8ΔprtV strain and study its role in pathogenesis in rabbit ileal loop model (RIL).Methodology/Principal FindingsWe partially purified the residual protease secreted by strain CHA6.8ΔprtV from culture supernatant by anion-exchange chromatography. The major protein band in native PAGE was identified by MS peptide mapping and sequence analysis showed homology with a 59-kDa trypsin-like serine protease encoded by VC1649. The protease activity was partially inhibited by 25 mM PMSF and 10 mM EDTA and completely inhibited by EDTA and PMSF together. RIL assay with culture supernatants of strains C6709 (FA ratio 1.1+/−0.3 n = 3), CHA6.8 (FA ratio 1.08+/−0.2 n = 3), CHA6.8ΔprtV (FA ratio 1.02+/−0.2 n = 3) and partially purified serine protease from CHA6.8ΔprtV (FA ratio 1.2+/−0.3 n = 3) induced fluid accumulation and histopathological studies on rabbit ileum showed destruction of the villus structure with hemorrhage in all layers of the mucosa. RIL assay with culture supernatant of CHA6.8ΔprtVΔVC1649 strain (FA ratio 0.11+/−0.005 n = 3) and with protease incubated with PMSF and EDTA (FA ratio 0.3+/−0.05 n = 3) induced a significantly reduced FA ratio with almost complete normal villus structure.ConclusionOur results show the presence of a novel 59-kDa serine protease in a ΔhapAΔprtV V. cholerae O1 strain and its role in hemorrhagic response in RIL model.

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Section: Discussionmentioning

confidence: 99%

Studies on a Novel Serine Protease of a ΔhapAΔprtV Vibrio cholerae O1 Strain and Its Role in Hemorrhagic Response in the Rabbit Ileal Loop Model

et al. 2010

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“…This region originated from prophage islands and is known to exist in two or more copies in pathogenic O1 strains (3,19,53,74). This could explain the presence of two amplification products (alleles) in the V. cholerae O1 In-124(ϩ) strain.…”

Section: Discussionmentioning

confidence: 99%

Vibrio cholerae Strain Typing and Phylogeny Study Based on Simple Sequence Repeats

et al. 2007

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Vibrio cholerae is the etiological agent of cholera. Its natural reservoir is the aquatic environment. To date, practical typing of V. cholerae is mainly serological and requires about 200 antisera. Simple sequence repeats (SSR), also termed VNTR (for variable number of tandem repeats), provide a source of high genomic polymorphism used in bacterial typing. Here we describe an SSR-based typing method that combines the variation in highly mutable SSR loci, with that of shorter, relatively more stable mononucleotide repeat (MNR) loci, for accurate and rapid typing of V. cholerae. Vibrio cholerae, a gram-negative bacterium, is the causal agent of the severe diarrheal disease cholera. Its natural reservoir is the aquatic environment (49, 84). Cholera pandemics are caused by specific serogroups of V. cholerae that are pathogenic only to humans (35,84). Since 1817, V. cholerae has caused a number of pandemics. The first seven were presumed to be caused by O1 serogroup of V. cholerae (68). In October 1992, a new serogroup, defined O139, caused a severe outbreak of cholera in southeast India. Within 10 months, the O139 serogroup was disseminated all over the Indian subcontinent and soon thereafter spread to 11 neighboring countries, temporarily displacing the O1 serogroups (64). Since then both serogroups coexist and are responsible for large outbreaks. Genomic studies indicated that O139 epidemic strain arose by horizontal acquisition of unique DNA (15, 47).Traditionally, V. cholerae classification is serological and requires about 200 antisera based on the somatic O antigen (72). Isolates of V. cholerae are divided into three major subgroups: O1, O139, and non-O1/non-O139, of which only the O1 and O139 serogroups are associated with cholera pandemics and epidemics. Non-O1, non-O139 serogroups are recognized as causative agents of sporadic and localized outbreaks (73). Pathogenic V. cholerae isolates carry virulence genes, such as the toxins genes ctxAB (25,65,68). The environmental V. cholerae strains from non-O1, non-O139 serogroups are a possible natural reservoir of potentially new emerging epidemic strains (67,73). This assumption is supported by the finding that some of these environmental strains harbor virulence genes (23) and thus are likely to evolve into novel pathogenic strains by horizontal gene transfer (24,25). The emergence of new pathogenic V. cholerae strains requires not only an efficient, rapid, and accurate identification tool but also a means for determining genetic relationships among environmental and clinical isolates.Genome-based bacterial identification and typing is essential for several disciplines, including taxonomy, epidemiology, determining phylogenetic relationships, and the study of evolutionary mechanisms. It allows distinguishing among strains within a species to monitor epidemics and routes of contamination. Recent advances in biotechnology have resulted in the development of numerous methods for microorganism typing that differ in their sensitivity, rapidity, complexity, discrimin...

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“…The first six pandemics were caused by the classical biotype, but after 1961 the V. cholerae El Tor biotype displaced the classical biotype (Kaper et al, 1995). There are certain structural and functional peculiarities in the pathogenicity genes of El Tor vibrios that make the symptoms of cholera milder but longer lasting than the symptoms of the classical biotype strains (Smirnova et al, 2004). However, in the recent past, evolution among El Tor strains by the emergence of hybrid biotype strains with altered cholera toxin (CT) has been noticed (Nair et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

A large cholera outbreak due to a new cholera toxin variant of the Vibrio cholerae O1 El Tor biotype in Orissa, Eastern India

Kumar

Jain

Goel

et al. 2009

Journal of Medical Microbiology

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A total of 32 Vibrio cholerae isolates were collected during a recent large cholera outbreak in Eastern India. Biochemical and serological studies revealed that all of the isolates belonged to serogroup O1, biotype El Tor, serotype Ogawa. Two multiplex PCR assays confirmed the presence of various toxigenic and pathogenic genes -ace, ctxAB, hlyA, ompU, ompW, rfbO1, rtx, tcp, toxR and zot -in all of the isolates. Sequencing of the ctxB gene from the isolates revealed a novel mutation in the gene. Sequencing also confirmed the presence of altered cholera toxin B of the classical biotype in all of the El Tor isolates, suggesting infection of isolates by classical CTXW. The molecular diversity of V. cholerae isolates studied by enterobacterial repetitive intergenic consensus sequence PCR, BOX-PCR and randomly amplified polymorphic DNA analysis uniformly showed the clonal relationship among the outbreak V. cholerae O1 isolates. The results of this study suggest that cholera-causing V. cholerae strains are constantly evolving in epidemic areas, highlighting the potential of the emergence of more virulent strains.

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Molecular–genetic peculiarities of classical biotype Vibrio cholerae, the etiological agent of the last outbreak Asiatic cholera in Russia

Cited by 9 publications

References 31 publications

Studies on a Novel Serine Protease of a ΔhapAΔprtV Vibrio cholerae O1 Strain and Its Role in Hemorrhagic Response in the Rabbit Ileal Loop Model

Studies on a Novel Serine Protease of a ΔhapAΔprtV Vibrio cholerae O1 Strain and Its Role in Hemorrhagic Response in the Rabbit Ileal Loop Model

Vibrio cholerae Strain Typing and Phylogeny Study Based on Simple Sequence Repeats

A large cholera outbreak due to a new cholera toxin variant of the Vibrio cholerae O1 El Tor biotype in Orissa, Eastern India

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