Isolation of Vibrio cholerae O1 strains similar to pre-seventh pandemic El Tor strains during an outbreak of gastrointestinal disease in an island resort in Fiji

Nair, G. Balakrish; Safa, Ashrafus; Bhuiyan, N. A.; Nusrin, Suraia; Murphy, Denise; Nicol, Carolyn; Valcanis, Mary; Iddings, Steven; Kubuabola, Ili; Vally, Hassan

doi:10.1099/jmm.0.46734-0

Cited by 25 publications

(20 citation statements)

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“…In 2009, an outbreak occurred in PNG, eventually reaching 8,997 cases by the end of 2010, with the highest incidence in the Madang Province [95], [96]. In addition, an outbreak was reported from a resort in Fiji [97]. In Australia, four cases, all imported were reported in 2009.…”

Section: Bacterial and Fungal Ntdsmentioning

confidence: 99%

Neglected Tropical Diseases of Oceania: Review of Their Prevalence, Distribution, and Opportunities for Control

et al. 2013

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Among Oceania's population of 35 million people, the greatest number living in poverty currently live in Papua New Guinea (PNG), Fiji, Vanuatu, and the Solomon Islands. These impoverished populations are at high risk for selected NTDs, including Necator americanus hookworm infection, strongyloidiasis, lymphatic filariasis (LF), balantidiasis, yaws, trachoma, leprosy, and scabies, in addition to outbreaks of dengue and other arboviral infections including Japanese encephalitis virus infection. PNG stands out for having the largest number of cases and highest prevalence for most of these NTDs. However, Australia's Aboriginal population also suffers from a range of significant NTDs. Through the Pacific Programme to Eliminate Lymphatic Filariasis, enormous strides have been made in eliminating LF in Oceania through programs of mass drug administration (MDA), although LF remains widespread in PNG. There are opportunities to scale up MDA for PNG's major NTDs, which could be accomplished through an integrated package that combines albendazole, ivermectin, diethylcarbamazine, and azithromycin, in a program of national control. Australia's Aboriginal population may benefit from appropriately integrated MDA into primary health care systems. Several emerging viral NTDs remain important threats to the region.

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Section: Bacterial and Fungal Ntdsmentioning

confidence: 99%

Neglected Tropical Diseases of Oceania: Review of Their Prevalence, Distribution, and Opportunities for Control

et al. 2013

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“…These incidents included a large outbreak in west Pakistan in 1968 and the appearance of the classical biotype in Bangladesh in 1979, with a continuous presence until the end of 1992 (5). However, since 2001, a series of reports have been published revealing clinical isolates, from as far back as the early 1990s, that are of El Tor biotype background but possess some classical biotype traits (3,4,28,34,35,36,43). For example, the ctxA gene, which is the first gene of the ctx phage operon and codes for the A subunit of the cholera toxin, is completely conserved in sequence between the two O1 biotypes.…”

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confidence: 99%

“…These clinical El Tor O1 strains were found to contain the classical biotype cholera toxin B subunit gene (ctxB) and have since been termed El Tor variants (34,39). These El Tor variants have become a major focus of research, since other El Tor variants also have been identified in Asia and Mozambique (29,34,35,38) and recently have been a focus of attention in Haiti (1,6,7,8,9). Of particular concern are the recently published results indicating that some of the clinically isolated El Tor variants produce different levels of cholera toxin, including some isolates that produce higher levels than classical biotype strains (16).…”

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confidence: 99%

“…Standard phenotypic assays, including polymyxin B resistance, hemolysis assays, phage sensitivities, and the Voges-Proskauer tests, are frequently employed in some combination (4,11,45). Genetic markers, such as the ctxB gene, have been used to distinguish the cholera toxin between classical and El Tor biotypes (11,33,35) to classify isolates as El Tor variants. The sequences of tcpA, which codes for the pilin subunits of the TcpA apparatus, and rstR, the repressor found in the RS1 element, which codes for the regulatory region for phage replication, also have been used in determining the biotypes of new isolates (4,11,39,45).…”

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confidence: 99%

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Characterization of Vibrio cholerae O1 El Tor Biotype Variant Clinical Isolates from Bangladesh and Haiti, Including a Molecular Genetic Analysis of Virulence Genes

et al. 2011

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Vibrio cholerae serogroup O1, the causative agent of the diarrheal disease cholera, is divided into two biotypes: classical and El Tor. Both biotypes produce the major virulence factors toxin-coregulated pilus (TCP) and cholera toxin (CT). Although possessing genotypic and phenotypic differences, El Tor biotype strains displaying classical biotype traits have been reported and subsequently were dubbed El Tor variants. Of particular interest are reports of El Tor variants that produce various levels of CT, including levels typical of classical biotype strains. Here, we report the characterization of 10 clinical isolates from the International Centre for Diarrhoeal Disease Research, Bangladesh, and a representative strain from the 2010 Haiti cholera outbreak. We observed that all 11 strains produced increased CT (2-to 10-fold) compared to that of wild-type El Tor strains under in vitro inducing conditions, but they possessed various TcpA and ToxT expression profiles. Particularly, El Tor variant MQ1795, which produced the highest level of CT and very high levels of TcpA and ToxT, demonstrated hypervirulence compared to the virulence of El Tor wild-type strains in the infant mouse cholera model. Additional genotypic and phenotypic tests were conducted to characterize the variants, including an assessment of biotype-distinguishing characteristics. Notably, the sequencing of ctxB in some El Tor variants revealed two copies of classical ctxB, one per chromosome, contrary to previous reports that located ctxAB only on the large chromosome of El Tor biotype strains.Vibrio cholerae is a Gram-negative, curved-rod-shaped bacterium that is the causative agent of the watery diarrheal disease cholera. The structure of the cell surface lipopolysaccharide O antigen is used to classify V. cholerae into more than 200 serogroups, of which only two, O1 and O139, possess the potential to cause epidemic or pandemic cholera. The O1 serogroup is further divided into two biotypes, classical and El Tor, which evolved from independent lineages (20, 22), and they display genotypic and phenotypic differences.V. cholerae O1 is distinguished by two of its major virulence factors, cholera toxin (CT) and the toxin-coregulated pilus (TCP). The cholera toxin is encoded by ctxA and ctxB, which are found on the CTX prophage (49), and is responsible for the manifestation of diarrheal disease with severe water and electrolyte loss. The TCP, encoded by the tcp operon in the Vibrio pathogenicity island (VPI), is required for V.

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“…This set of protocols details some of the different genetic and phenotypic assays commonly utilized when characterizing Vibrio cholerae clinical or environmental isolates (Lan and Reeves, 2002;Nair et al, 2002Nair et al, , 2006aAnsaruzzaman et al, 2004Ansaruzzaman et al, , 2007Safa et al, 2006). Basic Protocol 1 details a genetic screen commonly used to examine the sequences of the cholera toxin B subunit (ctxB; Nair et al, 2006a;Morita et al, 2008;Chatterjee et al, 2009) and the major pilin protein TcpA (tcpA; Safa et al, 2008;Chatterjee et al, 2009). Cholera toxin, composed of the A and B subunits, is the major virulence factor that is directly responsible for the rice-water diarrhea associated with The proteolysis assay performed on milk agar plates is suggestive of HapR-regulated protease activity.…”

Section: Introductionmentioning

confidence: 99%

Genetic Screens and Biochemical Assays to Characterize Vibrio cholerae O1 Biotypes: Classical and El Tor

Son

Taylor

2011

CP Microbiology

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Vibrio cholerae serogroup O1 has two biotypes, classical and El Tor, the latter of which has displaced the prior and has been the causative agent for the ongoing seventh pandemic. However, reports since 2001 have identified clinical isolates of El Tor that have classical O1 biotype genetic and phenotypic characteristics. These El Tor variants have been emerging in clinical settings with increased frequency, including the 2010 cholera outbreak in Haiti. The emergence of El Tor variants warrants the proper and timely identification of clinical (or environmental) isolates' biotype. This unit describes some quick and simple genetic screens and phenotypic assays (biochemical characterization), to be performed simultaneously, commonly used to distinguish biotype and initiate characterization of any clinical (or environmental) isolates of Vibrio cholerae O1. Curr. Protoc. Microbiol. 22:6A.2.1‐6A.2.17. © 2011 by John Wiley & Sons, Inc.

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Isolation of Vibrio cholerae O1 strains similar to pre-seventh pandemic El Tor strains during an outbreak of gastrointestinal disease in an island resort in Fiji

Cited by 25 publications

References 15 publications

Neglected Tropical Diseases of Oceania: Review of Their Prevalence, Distribution, and Opportunities for Control

Neglected Tropical Diseases of Oceania: Review of Their Prevalence, Distribution, and Opportunities for Control

Characterization of Vibrio cholerae O1 El Tor Biotype Variant Clinical Isolates from Bangladesh and Haiti, Including a Molecular Genetic Analysis of Virulence Genes

Genetic Screens and Biochemical Assays to Characterize Vibrio cholerae O1 Biotypes: Classical and El Tor

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