scholarly journals Analysis of 44 Vibrio anguillarum genomes reveals high genetic diversity

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10451
Author(s):  
Mie Johanne Hansen ◽  
Egle Kudirkiene ◽  
Inger Dalsgaard
Keyword(s):  
Genetic Diversity ◽  
Rainbow Trout ◽  
De Novo ◽  
Vibrio Anguillarum ◽  
Antibiotic Resistance Genes ◽  
Economic Losses ◽  
Nucleotide Polymorphisms ◽  
High Genetic Diversity ◽  
Pan Genome ◽  
Almost All

Vibriosis, a hemorrhagic septicemic disease caused by the bacterium Vibrio anguillarum, is an important bacterial infection in Danish sea-reared rainbow trout. Despite of vaccination, outbreaks still occur, likely because the vaccine is based on V. anguillarum strains from abroad/other hosts than rainbow trout. Information about the genetic diversity of V. anguillarum specifically in Danish rainbow trout, is required to investigate this claim. Consequently, the aim of the present investigation was to sequence and to characterize a collection of 44 V. anguillarum strains obtained primarily from vibriosis outbreaks in Danish rainbow trout. The strains were sequenced, de novo assembled, and the genomes examined for the presence of plasmids, virulence, and acquired antibiotic resistance genes. To investigate the phylogeny, single nucleotide polymorphisms were identified, and the pan-genome was calculated. All strains carried tet(34) encoding tetracycline resistance, and 36 strains also contained qnrVC6 for increased fluoroquinolone/quinolone resistance. But interestingly, all strains were phenotypic sensitive to both oxytetracycline and oxolinic acid. Almost all serotype O1 strains contained a pJM1-like plasmid and nine serotype O2A strains carried the plasmid p15. The distribution of virulence genes was rather similar across the strains, although evident variance among serotypes was observed. Most significant, almost all serotype O2 and O3 strains, as well as the serotype O1 strain without a pJM1-like plasmid, carried genes encoding piscibactin biosynthesis. Hence supporting the hypothesis, that piscibactin plays a crucial role in virulence for pathogenic strains lacking the anguibactin system. The phylogenetic analysis and pan-genome calculations revealed great diversity within V. anguillarum. Serotype O1 strains were in general very similar, whereas considerable variation was found among serotype O2A strains. The great diversity within the V. anguillarum serotype O2A genomes is most likely the reason why vaccines provide good protection from some strains, but not from others. Hopefully, the new genomic data and knowledge provided in this study might help develop an optimized vaccine against V. anguillarum in the future to reduce the use of antibiotics, minimize economic losses and improve the welfare of the fish.

scholarly journals High Genetic Diversity in Flavobacterium psychrophilum Isolates from Healthy Rainbow Trout (Oncorhynchus mykiss) Farmed in the Same Watershed, Revealed by Two Typing Methods

2020 ◽  
Vol 87 (2) ◽  
Author(s):  
Ségolène Calvez ◽  
Nora Navarro-Gonzalez ◽  
Charlène Siekoula-Nguedia ◽  
Catherine Fournel ◽  
Eric Duchaud
Keyword(s):  
Genetic Diversity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Clonal Complex ◽  
Economic Losses ◽  
High Genetic Diversity ◽  
Content Type ◽  
Flavobacterium Psychrophilum ◽  
Sequence Types ◽  
Apparently Healthy

ABSTRACT Flavobacterium psychrophilum affects salmonid health worldwide and causes economic losses. The genetic diversity of the pathogen must be considered to develop control methods. However, previous studies have reported both high and low levels of genetic diversity. The present longitudinal study aimed at assessing the genetic diversity of F. psychrophilum at a small temporal and geographic scale. Four farms located on the same watershed in France were studied. Rainbow trout (Oncorhynchus mykiss) batches were monitored, and apparently healthy individuals were sampled over 1 year. A total of 288 isolates were recovered from fish organs (gills and spleen) and eggs. Pulsed field gel electrophoresis revealed high genetic diversity. Multilocus sequence typing performed on a selection of 31 isolates provided congruent results, as follows: 18 sequence types (STs) were found, of which 13 were novel. The mean gene diversity (H = 0.8413) was much higher than that previously reported for this host species, although the sampling was restricted to a single watershed and 1 year. Seven isolates out of 31 were assigned to clonal complex ST10 (CC-ST10), which is the predominant clonal complex in the main salmonid production areas. A split decomposition tree reflected a panmictic population. This finding is important for aquaculture veterinarians in their diagnostic procedure, as the choice of adequate antibiotic treatment is conditioned by the correct identification of the causative agent. Furthermore, this study expands our knowledge on genetic diversity required for the development of an effective vaccine against F. psychrophilum. IMPORTANCE The bacterium Flavobacterium psychrophilum is a serious pathogen in many fish species, especially salmonids, that is responsible for considerable economic losses worldwide. In order to treat infections and to develop vaccines, the genetic diversity of this bacterium needs to be known. We assessed the genetic diversity of F. psychrophilum isolates from apparently healthy rainbow trout raised in several fish farms in the same watershed in France. Two different genotyping methods revealed high diversity. The majority of isolates were unrelated to clonal complex sequence type 10 (CC-ST10), the clonal complex that is predominant worldwide and associated with disease in rainbow trout. In addition, we found 13 novel sequence types. These results suggest that a diverse subpopulation of F. psychrophilum may be harbored by rainbow trout.

scholarly journals Bluetongue in Europe – the risk of animal import from restricted zones

2019 ◽  
Vol 75 (05) ◽  
pp. 6254-2019
Author(s):  
ANNA ORŁOWSKA ◽  
MARCIN SMRECZAK ◽  
JERZY ROLA
Keyword(s):  
Genetic Diversity ◽  
20Th Century ◽  
Bluetongue Virus ◽  
Viral Disease ◽  
Economic Losses ◽  
High Genetic Diversity ◽  
Key Factor ◽  
Vector Borne ◽  
Sentinel Animals ◽  
Free Status

Bluetongue (BT) is a vector-borne viral disease effecting ruminants caused by bluetongue virus (BTV), transmitted mainly by bites from midges of the genus Culicoides. Since the end of 20th century, BTV is endemic in several European countries and the disease is caused mainly by BTV-8 and BTV-4 infections. Bluetongue virus is characterized by high genetic diversity. To date, over 29 BTV serotypes have been documented, including recently discovered atypical serotypes BTV (25–27). The disease has a high economic impact as it causes economic losses due to animal mortality, reduced productivity and restrictions on the movement of animals. Several reports and numerous observations indicate the contribution of animal movements to the spread of BTV infections. Thus, bluetongue surveillance that includes testing of sentinel animals as well as virological testing of animals susceptible to BTV infection imported from restricted zones due to the presence of BTV is a key factor in maintaining a BT-free status

scholarly journals Large-Scale Analysis ofFlavobacterium psychrophilumMultilocus Sequence Typing Genotypes Recovered from North American Salmonids Indicates that both Newly Identified and Recurrent Clonal Complexes Are Associated with Disease

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Christopher Knupp ◽  
Gregory D. Wiens ◽  
Mohamed Faisal ◽  
Douglas R. Call ◽  
Kenneth D. Cain ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Rainbow Trout ◽  
North America ◽  
North American ◽  
Economic Losses ◽  
Content Type ◽  
Flavobacterium Psychrophilum ◽  
Coldwater Disease ◽  
Rainbow Trout Fry Syndrome ◽  
Bacterial Coldwater Disease

ABSTRACTFlavobacterium psychrophilum, the etiological agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), causes significant economic losses in salmonid aquaculture, particularly in rainbow trout (Oncorhynchus mykiss). Prior studies have used multilocus sequence typing (MLST) to examine genetic heterogeneity withinF. psychrophilum. At present, however, its population structure in North America is incompletely understood, as only 107 isolates have been genotyped. Herein, MLST was used to investigate the genetic diversity of an additional 314 North AmericanF. psychrophilumisolates that were recovered from ten fish host species from 20 U.S. states and 1 Canadian province over nearly four decades. These isolates were placed into 66 sequence types (STs), 47 of which were novel, increasing the number of clonal complexes (CCs) in North America from 7 to 12. Newly identified CCs were diverse in terms of host association, distribution, and association with disease. The largestF. psychrophilumCC identified was CC-ST10, within which 10 novel genotypes were discovered, most of which came fromO. mykissexperiencing BCWD. This discovery, among others, provides evidence for the hypothesis that ST10 (i.e., the founding ST of CC-ST10) originated in North America. Furthermore, ST275 (in CC-ST10) was recovered from wild/feral adult steelhead and marks the first recovery of CC-ST10 from wild/feral fish in North America. Analyses also revealed that at the allele level, the diversification ofF. psychrophilumin North America is driven three times more frequently by recombination than random nucleic acid mutation, possibly indicating how new phenotypes emerge within this species.IMPORTANCEFlavobacterium psychrophilumis the causative agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), both of which cause substantial losses in farmed fish populations worldwide. To better prevent and control BCWD and RTFS outbreaks, we sought to characterize the genetic diversity of several hundredF. psychrophilumisolates that were recovered from diseased fish across North America. Results highlighted multipleF. psychrophilumgenetic strains that appear to play an important role in disease events in North American aquaculture facilities and suggest that the practice of trading fish eggs has led to the continental and transcontinental spread of this bacterium. The knowledge generated herein will be invaluable toward guiding the development of future disease prevention techniques.

scholarly journals Genetics of Host Protection against Helicobacter pylori Infections

2021 ◽  
Vol 22 (6) ◽  
pp. 3192 ◽  
Author(s):  
Rosanna Capparelli ◽  
Domenico Iannelli
Keyword(s):  
Genetic Diversity ◽  
Helicobacter Pylori ◽  
T Regulatory Cells ◽  
Protective Role ◽  
Disease Genes ◽  
Nucleotide Polymorphisms ◽  
High Genetic Diversity ◽  
Host Protection ◽  
High Level

This narrative review discusses the genetics of protection against Helicobacter pylori (Hp) infection. After a brief overview of the importance of studying infectious disease genes, we provide a detailed account of the properties of Hp, with a view to those relevant for our topic. Hp displays a very high level of genetic diversity, detectable even between single colonies from the same patient. The high genetic diversity of Hp can be evaded by stratifying patients according to the infecting Hp strain. This approach enhances the power and replication of the study. Scanning for single nucleotide polymorphisms is generally not successful since genes rarely work alone. We suggest selecting genes to study from among members of the same family, which are therefore inclined to cooperate. Further, extending the analysis to the metabolism would significantly enhance the power of the study. This combined approach displays the protective role of MyD88, TIRAP, and IL1RL1 against Hp infection. Finally, several studies in humans have demonstrated that the blood T cell levels are under the genetic control of the CD39+ T regulatory cells (TREGS).

scholarly journals De novo developed microsatellite markers in gill parasites of the genus Dactylogyrus (Monogenea): revealing the phylogeographic pattern of population structure in the generalist parasite Dactylogyrus vistulae

2021 ◽  
Author(s):  
Michal Benovics ◽  
Lenka Gettová ◽  
Andrea Simková
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Microsatellite Markers ◽  
Parasite Species ◽  
De Novo ◽  
High Genetic Diversity ◽  
Genetic Studies ◽  
The North ◽  
Gill Parasites ◽  
Modern Population

Approaches using microsatellite markers are considered the gold standard for modern population-genetic studies. However, though they have found application in research into various platyhelminth taxa, they remained substantially underutilized in the study of monogeneans. In the present study, a newly-developed set of 24 microsatellite markers was used to investigate the genetic diversity of the generalist monogenean species D. vistulae. The analyzed parasite specimens were collected from 13 cyprinoid species from 11 sites in the Apennine and Balkan peninsulas. A total of 159 specimens were genotyped at each of the loci and the number of alleles per locus ranged from 2 to 16, with a mean number of 6.958 alleles per locus. Exceptionally high genetic diversity was observed among D. vistulae individuals in the southern Balkans, suggesting that this region might represent the center of diversification of the genus in Europe, from where Dactylogyrus parasites expanded into the north. The initial clustering analysis divided all investigated specimens into three major clusters; however, the results of the subsequent analyses revealed the existence of various subpopulations, suggesting that the population structure of D. vistulae is associated with the diversification of their cyprinoid hosts. In addition, partition of the parasite population was observed in regions of the sympatric occurrence of two host species, indicating that these hosts may represent a barrier to gene flow, even for generalist parasite species.

scholarly journals Genetic Diversity and Population Structure for Resistance and Susceptibility to Mastitis in Braunvieh Cattle

2021 ◽  
Vol 8 (12) ◽  
pp. 329
Author(s):  
Mitzilin Zuleica Trujano-Chavez ◽  
Reyna Sánchez-Ramos ◽  
Paulino Pérez-Rodríguez ◽  
Agustín Ruíz-Flores
Keyword(s):  
Genetic Diversity ◽  
Candidate Genes ◽  
Genetic Resistance ◽  
Principal Component ◽  
Clinical Mastitis ◽  
Snp Markers ◽  
Economic Losses ◽  
High Genetic Diversity ◽  
A Value ◽  
Candidate Loci

Mastitis is a disease that causes significant economic losses, since resistance to mastitis is a difficult trait to be improved due to its multifactorial occurrence. Therefore, our objective was to characterize a Mexican Braunvieh cattle population for genetic resistance and susceptibility to mastitis. We used 66 SNP markers for 45 candidate genes in 150 animals. The average heterozygosity was 0.445 ± 0.076, a value higher than those reported for some European breeds. The inbreeding coefficient was slightly negative for resistance to subclinical (−0.058 ± 0.055) and clinical (−0.034 ± 0.076) mastitis, possibly due to low selection for the immunological candidate genes that influence these traits. The genotypic profiles for the candidate loci per K-means group were obtained, as well as the group distribution through the graphics of the principal component analysis. The genotypic profiles showed high genetic diversity among groups. Resistance to clinical mastitis had the lowest presence of the heterozygous genotypes. Although the percentage of highly inbred animals (>50%) is up to 13.3%, there are highly heterozygous groups in terms of the studied traits, a favorable indicator of the presence of genetic diversity. The results of this study constitute evidence of the genetic potential of the Mexican Braunvieh population to improve mastitis-related traits.

scholarly journals Characterization of Potato Virus Y Isolates and Assessment of Nanopore Sequencing to Detect and Genotype Potato Viruses

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 478 ◽  
Author(s):  
Michele Della Bartola ◽  
Stephen Byrne ◽  
Ewen Mullins
Keyword(s):  
Genetic Diversity ◽  
Potato Virus ◽  
Potato Virus Y ◽  
De Novo ◽  
Solanum Tuberosum L ◽  
Germplasm Collection ◽  
Whole Genome Sequence ◽  
Nanopore Sequencing ◽  
High Genetic Diversity ◽  
Potato Viruses

Potato virus Y (PVY) is the most economically important virus infecting cultivated potato (Solanum tuberosum L.). Accurate diagnosis is crucial to regulate the trade of tubers and for the sanitary selection of plant material for propagation. However, high genetic diversity of PVY represents a challenge for the detection and classification of isolates. Here, the diversity of Irish PVY isolates from a germplasm collection and commercial sites was investigated using conventional molecular and serological techniques. Recombinant PVY isolates were prevalent, with PVYNTNa being the predominant genotype. In addition, we evaluated Nanopore sequencing to detect and reconstruct the whole genome sequence of four viruses (PVY, PVX, PVS, PLRV) and five PVY genotypes in a subset of eight potato plants. De novo assembly of Nanopore sequencing reads produced single contigs covering greater than 90% of the viral genome and sharing greater than 99.5% identity to the consensus sequences obtained with Illumina sequencing. Interestingly, single near full genome contigs were obtained for different isolates of PVY co-infecting the same plant. Mapping reads to available reference viral genomes enabled us to generate near complete genome sequences sharing greater than 99.90% identity to the Illumina-derived consensus. This is the first report describing the use of Oxford Nanopore’s MinION to detect and genotype potato viruses. We reconstructed the genome of PVY and other RNA viruses; indicating the technologies potential for virus detection in potato production systems, and for the study of genetic diversity of highly heterogeneous viruses such as PVY.

scholarly journals Genetic heterogeneity of Escherichia coli isolated from pasteurized milk in State of Paraná, Brazil

2014 ◽  
Vol 50 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Karine Oltramari ◽  
Rosilene Fressati Cardoso ◽  
Eliana Valéria Patussi ◽  
Adolfo Carlos Barreto Santos ◽  
Jane Martha Graton Mikcha
Keyword(s):  
Escherichia Coli ◽  
Genetic Diversity ◽  
Diarrheal Disease ◽  
Food Contamination ◽  
Economic Losses ◽  
High Morbidity ◽  
High Genetic Diversity ◽  
Pasteurized Milk ◽  
E Coli ◽  
Northwestern Region

Food contamination caused by enteric pathogens is a major cause of diarrheal disease worldwide, resulting in high morbidity and mortality and significant economic losses. Bacteria are important agents of foodborne diseases, particularly diarrheagenic Escherichia coli. The present study assessed the genetic diversity and antimicrobial resistance of E. coli isolates from pasteurized milk processed in 21 dairies in northwestern State of Parana, Brazil. The 95 E. coli isolates were subjected to antimicrobial susceptibility testing according to the recommendations of the Clinical and Laboratory Standards Institute and assessed genotypically by Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR). The highest rate of resistance was observed for cephalothin (55.78%). ERIC-PCR revealed high genetic diversity, clustering the 95 bacterial isolates into 90 different genotypic patterns. These results showed a heterogeneous population of E. coli in milk samples produced in the northwestern region of Paraná and the need for good manufacturing practices throughout the processing of pasteurized milk to reduce the risk of foodborne illnesses.

scholarly journals Comparison of Diplodia Tip Blight Pathogens in Spanish and North American Pine Ecosystems

2021 ◽  
Vol 9 (12) ◽  
pp. 2565
Author(s):  
Ana Aragonés ◽  
Tania Manzanos ◽  
Glen Stanosz ◽  
Isabel A. Munck ◽  
Rosa Raposo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genotypic Diversity ◽  
Economic Losses ◽  
Common Disease ◽  
Sample Type ◽  
High Genetic Diversity ◽  
The North ◽  
Low Genetic Diversity ◽  
Shoot Blight ◽  
North Of Spain

Diplodia tip blight is the most ubiquitous and abundant disease in Spanish Pinus radiata plantations. The economic losses in forest stands can be very severe because of its abundance in cones and seeds together with the low genetic diversity of the host. Pinus resinosa is not genetically diverse in North America either, and Diplodia shoot blight is a common disease. Disease control may require management designs to be adapted for each region. The genetic diversity of the pathogen could be an indicator of its virulence and spreading capacity. Our objective was to understand the diversity of Diplodia spp. in Spanish plantations and to compare it with the structure of American populations to collaborate in future management guidelines. Genotypic diversity was investigated using microsatellite markers. Eight loci (SS9–SS16) were polymorphic for the 322 isolates genotyped. The results indicate that Diplodia sapinea is the most frequent Diplodia species present in plantations of the north of Spain and has high genetic diversity. The higher genetic diversity recorded in Spain in comparison to previous studies could be influenced by the intensity of the sampling and the evidence about the remarkable influence of the sample type.

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