scholarly journals Population Genetics of Vibrio cholerae from Nepal in 2010: Evidence on the Origin of the Haitian Outbreak

mBio ◽  
2011 ◽  
Vol 2 (4) ◽  
Author(s):  
Rene S. Hendriksen ◽  
Lance B. Price ◽  
James M. Schupp ◽  
John D. Gillece ◽  
Rolf S. Kaas ◽  
...  
Keyword(s):  
United Nations ◽  
Natural Disasters ◽  
Vibrio Cholerae ◽  
Antimicrobial Susceptibility ◽  
International Travel ◽  
Whole Genome Sequence ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
The One ◽  
Epidemiological Link

ABSTRACT Cholera continues to be an important cause of human infections, and outbreaks are often observed after natural disasters, such as the one following the 2010 earthquake in Haiti. Once the cholera outbreak was confirmed, rumors spread that the disease was brought to Haiti by a battalion of Nepalese soldiers serving as United Nations peacekeepers. This possible connection has never been confirmed. We used whole-genome sequence typing (WGST), pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing to characterize 24 recent Vibrio cholerae isolates from Nepal and evaluate the suggested epidemiological link with the Haitian outbreak. The isolates were obtained from 30 July to 1 November 2010 from five different districts in Nepal. We compared the 24 genomes to 10 previously sequenced V. cholerae isolates, including 3 from the Haitian outbreak (began July 2010). Antimicrobial susceptibility and PFGE patterns were consistent with an epidemiological link between the isolates from Nepal and Haiti. WGST showed that all 24 V. cholerae isolates from Nepal belonged to a single monophyletic group that also contained isolates from Bangladesh and Haiti. The Nepalese isolates were divided into four closely related clusters. One cluster contained three Nepalese isolates and three Haitian isolates that were almost identical, with only 1- or 2-bp differences. Results in this study are consistent with Nepal as the origin of the Haitian outbreak. This highlights how rapidly infectious diseases might be transmitted globally through international travel and how public health officials need advanced molecular tools along with standard epidemiological analyses to quickly determine the sources of outbreaks. IMPORTANCE Cholera is one of the ancient classical diseases and particularly prone to cause major outbreaks following major natural disasters, such as earthquakes and hurricanes, where the normal separation between sewage and drinking water is destroyed. This was the case following the 2010 earthquake in Haiti. Rumors spread that the disease was brought to Haiti by a battalion of Nepalese soldiers serving as United Nations peacekeepers. This possible connection has never been confirmed. Sequencing the genomes of bacteria can give detailed information on whether isolates from different sites share a common origin. We used this technology to sequence isolates of Vibrio cholerae from Nepal, identify single-nucleotide polymorphisms (SNPs), and compare these high-resolution genotypes to the complete genome sequences of isolates from the Haiti outbreak. We provide support for the hypothesis that the isolates were brought to Haiti from Nepal.

scholarly journals High Frequency of a Novel Filamentous Phage, VCYϕ, within an Environmental Vibrio cholerae Population

2011 ◽  
Vol 78 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Hong Xue ◽  
Yan Xu ◽  
Yan Boucher ◽  
Martin F. Polz
Keyword(s):  
Vibrio Cholerae ◽  
Sequence Similarity ◽  
Host Population ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Filamentous Phage ◽  
Nucleotide Polymorphisms ◽  
Environmental Biology ◽  
Content Type ◽  
Filamentous Phages

ABSTRACTEnvironmentalVibrio choleraestrains isolated from a coastal brackish pond (Oyster Pond, Woods Hole, MA) carried a novel filamentous phage, VCYϕ, which can exist as a host genome integrative form (IF) and a plasmid-like replicative form (RF). Outside the cell, the phage displays a morphology typical ofInovirus, with filamentous particles ∼1.8 μm in length and 7 nm in width. Four independent RF isolates had identical genomes, except for 8 single nucleotide polymorphisms clustered in two regions. The overall genome size is 7,103 bp with 11 putative open reading frames organized into three functional modules (replication, structure and assembly, and regulation). VCYϕ shares sequence similarity with other filamentous phages (including cholera disease-associated CTX) in a highly mosaic manner, indicating evolution by horizontal gene transfer and recombination. VCYϕ integrates in the vicinity of the putative translation initiation factor Sui1 in chromosome II ofV. cholerae. A screen of 531 closely related host isolates showed that ∼40% harbored phages, with 27% and 13% carrying the IF and RF, respectively. The relative frequencies of the RF and IF differed among strains isolated from the pond or lagoon of Oyster Pond, suggesting that the host habitat influences intracellular phage biology. The overall high prevalence within the host population shows that filamentous phages can be an important component of the environmental biology ofV. cholerae.

scholarly journals Genomic Epidemiology of the Haitian Cholera Outbreak: a Single Introduction Followed by Rapid, Extensive, and Continued Spread Characterized the Onset of the Epidemic

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Mark Eppinger ◽  
Talima Pearson ◽  
Sara S. K. Koenig ◽  
Ofori Pearson ◽  
Nathan Hicks ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Whole Genome Sequence ◽  
Epidemiological Surveillance ◽  
Molecular Evidence ◽  
Whole Genome ◽  
Cholera Outbreak ◽  
Content Type ◽  
Genomic Epidemiology ◽  
Southern Asia ◽  
Strain Collection

ABSTRACT For centuries, cholera has been one of the most feared diseases. The causative agent Vibrio cholerae is a waterborne Gram-negative enteric pathogen eliciting a severe watery diarrheal disease. In October 2010, the seventh pandemic reached Haiti, a country that had not experienced cholera for more than a century. By using whole-genome sequence typing and mapping strategies of 116 serotype O1 strains from global sources, including 44 Haitian genomes, we present a detailed reconstructed evolutionary history of the seventh pandemic with a focus on the Haitian outbreak. We catalogued subtle genomic alterations at the nucleotide level in the genome core and architectural rearrangements from whole-genome map comparisons. Isolates closely related to the Haitian isolates caused several recent outbreaks in southern Asia. This study provides evidence for a single-source introduction of cholera from Nepal into Haiti followed by rapid, extensive, and continued clonal expansion. The phylogeographic patterns in both southern Asia and Haiti argue for the rapid dissemination of V. cholerae across the landscape necessitating real-time surveillance efforts to complement the whole-genome epidemiological analysis. As eradication efforts move forward, phylogeographic knowledge will be important for identifying persistent sources and monitoring success at regional levels. The results of molecular and epidemiological analyses of this outbreak suggest that an indigenous Haitian source of V. cholerae is unlikely and that an indigenous source has not contributed to the genomic evolution of this clade. IMPORTANCE In this genomic epidemiology study, we have applied high-resolution whole-genome-based sequence typing methodologies on a comprehensive set of genome sequences that have become available in the aftermath of the Haitian cholera epidemic. These sequence resources enabled us to reassess the degree of genomic heterogeneity within the Vibrio cholerae O1 serotype and to refine boundaries and evolutionary relationships. The established phylogenomic framework showed how outbreak isolates fit into the global phylogeographic patterns compared to a comprehensive globally and temporally diverse strain collection and provides strong molecular evidence that points to a nonindigenous source of the 2010 Haitian cholera outbreak and refines epidemiological standards used in outbreak investigations for outbreak inclusion/exclusion following the concept of genomic epidemiology. The generated phylogenomic data have major public health relevance in translating sequence-based information to assist in future diagnostic, epidemiological, surveillance, and forensic studies of cholera.

scholarly journals Characterization of VCC-1, a Novel Ambler Class A Carbapenemase from Vibrio cholerae Isolated from Imported Retail Shrimp Sold in Canada

2016 ◽  
Vol 60 (3) ◽  
pp. 1819-1825 ◽  
Author(s):  
Chand S. Mangat ◽  
David Boyd ◽  
Nicol Janecko ◽  
Sarah-Lynn Martz ◽  
Andrea Desruisseau ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Vibrio Cholerae ◽  
Sequence Similarity ◽  
Laboratory Strain ◽  
Bioinformatic Analysis ◽  
Whole Genome Sequence ◽  
Large Chromosome ◽  
Human Consumption ◽  
Content Type ◽  
Class A

One of the core goals of the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) is to monitor major meat commodities for antimicrobial resistance. Targeted studies with methodologies based on core surveillance protocols are used to examine other foods, e.g., seafood, for antimicrobial resistance to detect resistances of concern to public health. Here we report the discovery of a novel Ambler class A carbapenemase that was identified in a nontoxigenic strain ofVibrio cholerae(N14-02106) isolated from shrimp that was sold for human consumption in Canada.V. choleraeN14-02106 was resistant to penicillins, carbapenems, and monobactam antibiotics; however, PCR did not detect common β-lactamases. Bioinformatic analysis of the whole-genome sequence ofV. choleraeN14-02106 revealed on the large chromosome a novel carbapenemase (referred to here as VCC-1, forVibriocholeraecarbapenemase1) with sequence similarity to class A enzymes. Two copies ofblaVCC-1separated and flanked by ISVch9(i.e., 3 copies of ISVch9) were found in an acquired 8.5-kb region inserted into a VrgG family protein gene. ClonedblaVCC-1conferred a β-lactam resistance profile similar to that inV. choleraeN14-02106 when it was transformed into a susceptible laboratory strain ofEscherichia coli. Purified VCC-1 was found to hydrolyze penicillins, 1st-generation cephalosporins, aztreonam, and carbapenems, whereas 2nd- and 3rd-generation cephalosporins were poor substrates. Using nitrocefin as a reporter substrate, VCC-1 was moderately inhibited by clavulanic acid and tazobactam but not EDTA. In this report, we present the discovery of a novel class A carbapenemase from the food supply.

scholarly journals Whole-Genome Sequencing of Vibrio cholerae O1 El Tor Strains Isolated in Ukraine (2011) and Russia (2014)

2017 ◽  
Vol 5 (8) ◽  
Author(s):  
Nina I. Smirnova ◽  
Yaroslav M. Krasnov ◽  
Elena Y. Agafonova ◽  
Elena Y. Shchelkanova ◽  
Zhanna V. Alkhova ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Genome Sequencing ◽  
Genetic Similarity ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Content Type ◽  
Vibrio Cholerae O1 ◽  
El Tor ◽  
Highly Virulent ◽  
High Genetic Similarity

ABSTRACT Here, we present the draft whole-genome sequence of Vibrio cholerae O1 El Tor strains 76 and M3265/80, isolated in Mariupol, Ukraine, and Moscow, Russia. The presence of various mutations detected in virulence-associated mobile elements indicates high genetic similarity of the strains reported here with new highly virulent variants of the cholera agent V. cholerae.

scholarly journals Salmonella entericaPhylogeny Based on Whole-Genome Sequencing Reveals Two New Clades and Novel Patterns of Horizontally Acquired Genetic Elements

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Jay Worley ◽  
Jianghong Meng ◽  
Marc W. Allard ◽  
Eric W. Brown ◽  
Ruth E. Timme
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Foodborne Pathogens ◽  
Bacterial Species ◽  
Whole Genome Sequence ◽  
Nucleotide Sequencing ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
Genetic Elements

ABSTRACTUsing whole-genome sequence (WGS) data from the GenomeTrakr network, a globally distributed network of laboratories sequencing foodborne pathogens, we present a new phylogeny ofSalmonella entericacomprising 445 isolates from 266 distinct serovars and originating from 52 countries. This phylogeny includes two previously unidentifiedS. entericasubsp.entericaclades. Serovar Typhi is shown to be nested within clade A. Our findings are supported by both phylogenetic support, based on a core genome alignment, and Bayesian approaches, based on single-nucleotide polymorphisms. Serovar assignments were refined byin silicoanalysis using SeqSero. More than 10% of serovars were either polyphyletic or paraphyletic. We found variable genetic content in these isolates relating to gene mobilization and virulence factors which have different distributions within clades. Gifsy-1- and Gifsy-2-like phages appear more prevalent in clade A; other viruses are more evenly distributed. Our analyses reveal IncFII is the predominant plasmid replicon inS. enterica. Few core or clade-defining virulence genes are observed, and their distributions appear probabilistic in nature. Together, these patterns demonstrate that genetic exchange withinS. entericais more extensive and frequent than previously realized, which significantly alters how we view the genetic structure of the bacterial species.IMPORTANCERapid improvements in nucleotide sequencing access and affordability have led to a drastic increase in availability of genetic information. This information will improve the accuracy of molecular descriptions, including serovars, withinS. enterica. Although the concept of serovars continues to be useful, it may have more significant limitations than previously understood. Furthermore, the discrete absence or presence of specific genes can be an unstable indicator of phylogenetic identity. Whole-genome sequencing provides more rigorous tools for assessing the distributions of these genes. Our phylogenetic and genetic content analyses reveal how active genetic elements are dynamically distributed within a species, allowing us to better understand genetic reservoirs and underlying bacterial evolution.

scholarly journals Development of a Multilocus Sequence Typing Tool for High-Resolution Genotyping of Enterocytozoon bieneusi

2011 ◽  
Vol 77 (14) ◽  
pp. 4822-4828 ◽  
Author(s):  
Yaoyu Feng ◽  
Na Li ◽  
Theresa Dearen ◽  
Maria L. Lobo ◽  
Olga Matos ◽  
...  
Keyword(s):  
High Resolution ◽  
Multilocus Sequence Typing ◽  
Enterocytozoon Bieneusi ◽  
Whole Genome Sequence ◽  
Rrna Gene ◽  
Content Type ◽  
Health Significance ◽  
The One ◽  
Pcr Targeting ◽  
Typing Tool

ABSTRACTThus far, genotyping ofEnterocytozoon bieneusihas been based solely on DNA sequence analysis of the internal transcribed spacer (ITS) of the rRNA gene. Both host-adapted and zoonotic (human-pathogenic) genotypes ofE. bieneusihave been identified. In this study, we searched for microsatellite and minisatellite sequences in the whole-genome sequence database ofE. bieneusiisolate H348. Seven potential targets (MS1 to MS7) were identified. Testing of the seven targets by PCR using two human-pathogenicE. bieneusigenotypes (A and Peru10) led to the selection of four targets (MS1, MS3, MS4, and MS7). Further analysis of the four loci with an additional 24 specimens of both host-adapted and zoonoticE. bieneusigenotypes indicated that most host-adapted genotypes were not amplified by PCR targeting these loci. In contrast, 10 or 11 of the 13 specimens of the zoonotic genotypes were amplified by PCR at each locus. Altogether, 12, 8, 7, and 11 genotypes of were identified at MS1, MS3, MS4, and MS7, respectively. Phylogenetic analysis of the nucleotide sequences obtained produced a genetic relationship that was similar to the one at the ITS locus, with the formation of a large group of zoonotic genotypes that included mostE. bieneusigenotypes in humans. Thus, a multilocus sequence typing tool was developed for high-resolution genotyping ofE. bieneusi.Data obtained in the study should also have implications for understanding the taxonomy ofEnterocytozoonspp., the public health significance ofE. bieneusiin animals, and the sources of humanE. bieneusiinfections.

scholarly journals Single Nucleotide Polymorphisms in Regulator-Encoding Genes Have an Additive Effect on Virulence Gene Expression in a Vibrio cholerae Clinical Isolate

mSphere ◽  
2016 ◽  
Vol 1 (5) ◽  
Author(s):  
Bailey M. Carignan ◽  
Kyle D. Brumfield ◽  
Mike S. Son
Keyword(s):  
Infectious Disease ◽  
Disease Progression ◽  
Vibrio Cholerae ◽  
Mortality Rates ◽  
Watery Diarrhea ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Content Type ◽  
Virulent Strains ◽  
Acute Watery Diarrhea

ABSTRACT Cholera, an infectious disease of the small intestine caused by the aquatic bacterium Vibrio cholerae, often results in vomiting and acute watery diarrhea. If left untreated or if the response is too slow, the symptoms can quickly lead to extreme dehydration and ultimately death of the patient. Recent anecdotal evidence of cholera patients suffering from increasingly severe symptoms and of disease progression at a much higher rate than previously observed has emerged. As recent cholera outbreaks caused by increasingly virulent strains have resulted in higher mortality rates, the need to investigate the mechanism(s) allowing this observed increased virulence is apparent. The significance of our research is in identifying the mechanism for increased virulence capabilities, which will allow the development of a model that will greatly enhance our understanding of cholera disease and V. cholerae pathogenesis, leading to broader biomedical impacts, as cholera serves as a model for other enteric diarrheal diseases. Vibrio cholerae is the etiological agent of the infectious disease cholera, which is characterized by vomiting and severe watery diarrhea. Recently, V. cholerae clinical isolates have demonstrated increased virulence capabilities, causing more severe symptoms with a much higher rate of disease progression than previously observed. We have identified single nucleotide polymorphisms (SNPs) in four virulence-regulatory genes (hapR, hns, luxO, and vieA) of a hypervirulent V. cholerae clinical isolate, MQ1795. Herein, all SNPs and SNP combinations of interest were introduced into the prototypical El Tor reference strain N16961, and the effects on the production of numerous virulence-related factors, including cholera toxin (CT), the toxin-coregulated pilus (TCP), and ToxT, were analyzed. Our data show that triple-SNP (hapR hns luxO and hns luxO vieA) and quadruple-SNP combinations produced the greatest increases in CT, TCP, and ToxT production. The hns and hns luxO SNP combinations were sufficient for increased TCP and ToxT production. Notably, the hns luxO vieA triple-SNP combination strain produced TCP and ToxT levels similar to those of MQ1795. Certain SNP combinations (hapR and hapR vieA) had the opposite effect on CT, TCP, and ToxT expression. Interestingly, the hns vieA double-SNP combination strain increased TCP production while decreasing CT production. Our findings suggest that SNPs identified in the four regulatory genes, in various combinations, are associated with increased virulence capabilities observed in V. cholerae clinical isolates. These studies provide insight into the evolution of highly virulent strains. IMPORTANCE Cholera, an infectious disease of the small intestine caused by the aquatic bacterium Vibrio cholerae, often results in vomiting and acute watery diarrhea. If left untreated or if the response is too slow, the symptoms can quickly lead to extreme dehydration and ultimately death of the patient. Recent anecdotal evidence of cholera patients suffering from increasingly severe symptoms and of disease progression at a much higher rate than previously observed has emerged. As recent cholera outbreaks caused by increasingly virulent strains have resulted in higher mortality rates, the need to investigate the mechanism(s) allowing this observed increased virulence is apparent. The significance of our research is in identifying the mechanism for increased virulence capabilities, which will allow the development of a model that will greatly enhance our understanding of cholera disease and V. cholerae pathogenesis, leading to broader biomedical impacts, as cholera serves as a model for other enteric diarrheal diseases.

scholarly journals Staphylococcus aureus CC398: Host Adaptation and Emergence of Methicillin Resistance in Livestock

mBio ◽  
2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Lance B. Price ◽  
Marc Stegger ◽  
Henrik Hasman ◽  
Maliha Aziz ◽  
Jesper Larsen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Phylogenetic Analyses ◽  
Antibiotic Use ◽  
Animal Production ◽  
Whole Genome Sequence ◽  
Nucleotide Polymorphisms ◽  
Methicillin Resistant ◽  
Content Type ◽  
Food Animal

ABSTRACTSince its discovery in the early 2000s, methicillin-resistantStaphylococcus aureus(MRSA) clonal complex 398 (CC398) has become a rapidly emerging cause of human infections, most often associated with livestock exposure. We applied whole-genome sequence typing to characterize a diverse collection of CC398 isolates (n= 89), including MRSA and methicillin-susceptibleS. aureus(MSSA) from animals and humans spanning 19 countries and four continents. We identified 4,238 single nucleotide polymorphisms (SNPs) among the 89 core genomes. Minimal homoplasy (consistency index = 0.9591) was detected among parsimony-informative SNPs, allowing for the generation of a highly accurate phylogenetic reconstruction of the CC398 clonal lineage. Phylogenetic analyses revealed that MSSA from humans formed the most ancestral clades. The most derived lineages were composed predominantly of livestock-associated MRSA possessing three different staphylococcal cassette chromosomemecelement (SCCmec) types (IV, V, and VII-like) including nine subtypes. The human-associated isolates from the basal clades carried phages encoding human innate immune modulators that were largely missing among the livestock-associated isolates. Our results strongly suggest that livestock-associated MRSA CC398 originated in humans as MSSA. The lineage appears to have undergone a rapid radiation in conjunction with the jump from humans to livestock, where it subsequently acquired tetracycline and methicillin resistance. Further analyses are required to estimate the number of independent genetic events leading to the methicillin-resistant sublineages, but the diversity of SCCmecsubtypes is suggestive of strong and diverse antimicrobial selection associated with food animal production.IMPORTANCEModern food animal production is characterized by densely concentrated animals and routine antibiotic use, which may facilitate the emergence of novel antibiotic-resistant zoonotic pathogens. Our findings strongly support the idea that livestock-associated MRSA CC398 originated as MSSA in humans. The jump of CC398 from humans to livestock was accompanied by the loss of phage-carried human virulence genes, which likely attenuated its zoonotic potential, but it was also accompanied by the acquisition of tetracycline and methicillin resistance. Our findings exemplify a bidirectional zoonotic exchange and underscore the potential public health risks of widespread antibiotic use in food animal production.

scholarly journals Whole-Genome Sequence of a Reemerging Listeria monocytogenes Serovar 1/2a Strain in Central Italy

2018 ◽  
Vol 7 (23) ◽  
Author(s):  
Massimiliano Orsini ◽  
Marina Torresi ◽  
Claudio Patavino ◽  
Patrizia Centorame ◽  
Antonio Rinaldi ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Single Nucleotide Polymorphisms ◽  
Genome Sequence ◽  
Central Italy ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Content Type

We report the whole-genome sequence of a Listeria monocytogenes strain isolated from a child in central Italy. Interestingly, the sequence showed a difference of only 13 single-nucleotide polymorphisms (SNPs) from a strain responsible for a severe listeriosis outbreak that occurred between January 2015 and March 2016 in the same region.

scholarly journals Acquisition and Evolution of SXT-R391 Integrative Conjugative Elements in the Seventh-Pandemic Vibrio cholerae Lineage

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Matteo Spagnoletti ◽  
Daniela Ceccarelli ◽  
Adrien Rieux ◽  
Marco Fondi ◽  
Elisa Taviani ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Vibrio Cholerae ◽  
Temporal Dynamics ◽  
Phylogenetic Analyses ◽  
Bacterial Species ◽  
Snp Analysis ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
Clinical Strains ◽  
Integrative Conjugative Elements

ABSTRACT SXT-R391 Integrative conjugative elements (ICEs) are self-transmissible mobile genetic elements able to confer multidrug resistance and other adaptive features to bacterial hosts, including Vibrio cholerae, the causative agent of cholera. ICEs are arranged in a mosaic genetic structure composed of a conserved backbone interspersed with variable DNA clusters located in conserved hot spots. In this study, we investigated ICE acquisition and subsequent microevolution in pandemic V. cholerae. Ninety-six ICEs were retrieved from publicly available sequence databases from V. cholerae clinical strains and were compared to a set of reference ICEs. Comparative genomics highlighted the existence of five main ICE groups with a distinct genetic makeup, exemplified by ICEVchInd5, ICEVchMoz10, SXT, ICEVchInd6, and ICEVchBan11. ICEVchInd5 (the most frequent element, represented by 70 of 96 elements analyzed) displayed no sequence rearrangements and was characterized by 46 single nucleotide polymorphisms (SNPs). SNP analysis revealed that recent inter-ICE homologous recombination between ICEVchInd5 and other ICEs circulating in gammaproteobacteria generated ICEVchMoz10, ICEVchInd6, and ICEVchBan11. Bayesian phylogenetic analyses indicated that ICEVchInd5 and SXT were independently acquired by the current pandemic V. cholerae O1 and O139 lineages, respectively, within a period of only a few years. IMPORTANCE SXT-R391 ICEs have been recognized as key vectors of antibiotic resistance in the seventh-pandemic lineage of V. cholerae, which remains a major cause of mortality and morbidity on a global scale. ICEs were acquired only recently in this clade and are acknowledged to be major contributors to horizontal gene transfer and the acquisition of new traits in bacterial species. We have reconstructed the temporal dynamics of SXT-R391 ICE acquisition and spread and have identified subsequent recombination events generating significant diversity in ICEs currently circulating among V. cholerae clinical strains. Our results showed that acquisition of SXT-R391 ICEs provided the V. cholerae seventh-pandemic lineage not only with a multidrug resistance phenotype but also with a powerful molecular tool for rapidly accessing the pan-genome of a large number of gammaproteobacteria.

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