scholarly journals Two Boundaries Separate Borrelia burgdorferi Populations in North America

2012 ◽  
Vol 78 (17) ◽  
pp. 6059-6067 ◽  
Author(s):  
Gabriele Margos ◽  
Jean I. Tsao ◽  
Santiago Castillo-Ramírez ◽  
Yvette A. Girard ◽  
Sarah A. Hamer ◽  
...  
Keyword(s):  
Population Structure ◽  
North America ◽  
Borrelia Burgdorferi ◽  
Surface Protein ◽  
Control Measures ◽  
Effective Control ◽  
Ancestral Population ◽  
Genetic Characteristics ◽  
Content Type ◽  
Continental Scale

ABSTRACTUnderstanding the spread of infectious diseases is crucial for implementing effective control measures. For this, it is important to obtain information on the contemporary population structure of a disease agent and to infer the evolutionary processes that may have shaped it. Here, we investigate on a continental scale the population structure ofBorrelia burgdorferi, the causative agent of Lyme borreliosis (LB), a tick-borne disease, in North America. We test the hypothesis that the observed population structure is congruent with recent population expansions and that these were preceded by bottlenecks mostly likely caused by the near extirpation in the 1900s of hosts required for sustaining tick populations. Multilocus sequence typing and complementary population analytical tools were used to evaluateB. burgdorferisamples collected in the Northeastern, Upper Midwestern, and Far-Western United States and Canada. The spatial distribution of sequence types (STs) and inferred population boundaries suggest that the current populations are geographically separated. One major population boundary separated westernB. burgdorferipopulations transmitted byIxodes pacificusin California from Eastern populations transmitted byI. scapularis; the other divided Midwestern and Northeastern populations. However, populations from all three regions were genetically closely related. Together, our findings suggest that although the contemporary populations of North AmericanB. burgdorferinow comprise three geographically separated subpopulations with no or limited gene flow among them, they arose from a common ancestral population. A comparative analysis of theB. burgdorferiouter surface protein C (ospC) gene revealed novel linkages and provides additional insights into the genetic characteristics of strains.

scholarly journals Evaluation of RevA, a Fibronectin-Binding Protein of Borrelia burgdorferi, as a Potential Vaccine Candidate for Lyme Disease

2013 ◽  
Vol 20 (6) ◽  
pp. 892-899 ◽  
Author(s):  
Angela M. Floden ◽  
Tammy Gonzalez ◽  
Robert A. Gaultney ◽  
Catherine A. Brissette
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Passive Immunization ◽  
Surface Protein ◽  
Surface Expression ◽  
Content Type ◽  
Good Target ◽  
Potential Vaccine ◽  
Mammalian Infection

ABSTRACTPrevious studies indicated that the Lyme disease spirocheteBorrelia burgdorferiexpresses the RevA outer surface protein during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA appears to be a good target for preventive therapies. RevA proteins are highly conserved across all Lyme borreliae, and antibodies against RevA protein are cross-reactive among RevA proteins from diverse strains. Mice infected withB. burgdorferimounted a rapid IgM response to RevA, followed by a strong IgG response that generally remained elevated for more than 12 months, suggesting continued exposure of RevA protein to the immune system. RevA antibodies were bactericidalin vitro. To evaluate the RevA antigen as a potential vaccine, mice were vaccinated with recombinant RevA and challenged withB. burgdorferiby inoculation with a needle or by a tick bite. Cultured tissues from all treatment groups were positive forB. burgdorferi. Vaccinated animals also appeared to have similar levels ofB. burgdorferiDNA compared to nonvaccinated controls. Despite its antigenicity, surface expression, and the production of bactericidal antibodies against it, RevA does not protect againstBorrelia burgdorferiinfection in a mouse model. However, passive immunization with anti-RevA antibodies did prevent infection, suggesting the possible utility of RevA-based immunotherapeutics or vaccine.

scholarly journals Uso de la Estructura de tallas como evidencia del establecimiento poblacional del pez león Pterois volitans (Scorpaeniformes: Scorpaenidae) en el sur del Caribe Mexicano.

2016 ◽  
Vol 64 (1) ◽  
pp. 353 ◽  
Author(s):  
Miguel Mateo Sabido-Itzá ◽  
Alejandro Medina-Quej ◽  
Alberto De Jesús-Navarrete ◽  
Jorge Manuel Gómez-Poot ◽  
María Del Carmen García-Rivas
Keyword(s):  
Population Structure ◽  
Ecological Study ◽  
Population Monitoring ◽  
Control Measures ◽  
Effective Control ◽  
Control Actions ◽  
Mexican Caribbean ◽  
Back Calculation ◽  
Continuous Population ◽  
Negative Impacts

The lionfish (P. volitans) has now invaded all the Mexican Caribbean and Gulf of Mexico, with the potential to cause negative impacts on the reefs. In the South Mexican Caribbean was firstly reported in July 2009, and six years after this report, some control measures such as fish tournament and local marketing have been implemented. However, information on its biology and invasion is still-lacking, so this study analyzed the population structure of 2 164 organisms collected from 2009 to 2012. An increase was observed in sizes for each year averaging Total length (Tl): 118 ± 34.8, 133 ± 56.3, 187 ± 74.8 and 219 ± 72.4 mm, respectively. Lionfish establishment at the study site is shown for the presence of juveniles’ sizes 20 mm TL up to 375 mm TL. When the back-calculation was obtained, we estimated that the larger fish could have recruited in early 2006, three years before the first report was made. A continuous population monitoring and an ecological study, will allow us to clarify the real impact in the ecosystems of the region and so to propose the most effective control actions.

scholarly journals Colistin-Nonsusceptible Pseudomonas aeruginosa Sequence Type 654 withblaNDM-1Arrives in North America

2016 ◽  
Vol 60 (3) ◽  
pp. 1794-1800 ◽  
Author(s):  
L. F. Mataseje ◽  
G. Peirano ◽  
D. L. Church ◽  
J. Conly ◽  
M. Mulvey ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
North America ◽  
Indian Subcontinent ◽  
Sequence Type ◽  
Control Measures ◽  
Infection Prevention And Control ◽  
Content Type ◽  
First Report ◽  
Prevention And Control Measures ◽  
Prolonged Hospital

This study describes 3 differentblaNDM-1genetic platforms in 3 different species obtained from the same patient who was directly transferred to an institution in Calgary, Alberta, Canada, following a prolonged hospital stay in India. TheblaNDM-1in theEscherichia coliisolate was located on a 176-kb IncA/C plasmid contained within an ISCR1region. TheblaNDM-1in theProvidencia rettgeriisolate was located on a 117-kb IncT plasmid contained within Tn3000, while theblaNDM-1in thePseudomonas aeruginosaisolate was located on the chromosome within an ISCR3region. This report highlights the plasticity of the genetic regions and environments associated withblaNDM-1. To the best of our knowledge, this is the first report ofP. aeruginosawithblaNDM-1identified in North America and the first report ofblaOXA-181inP. rettgeri. TheP. aeruginosaisolate belonged to the international high-risk sequence type 654 clone and was nonsusceptible to colistin. This case emphasizes the need for the use of appropriate infection prevention and control measures and vigilant screening for carbapenem-resistant Gram-negative bacteria in patients with a history of travel to areas of endemicity, such as the Indian subcontinent.

scholarly journals A Large, Refractory Nosocomial Outbreak of Klebsiella pneumoniae Carbapenemase-Producing Escherichia coli Demonstrates Carbapenemase Gene Outbreaks Involving Sink Sites Require Novel Approaches to Infection Control

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
V. Decraene ◽  
H. T. T. Phan ◽  
R. George ◽  
D. H. Wyllie ◽  
O. Akinremi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Control Measures ◽  
Effective Control ◽  
Infection Prevention And Control ◽  
Content Type ◽  
E Coli ◽  
Incidence Trends ◽  
Carbapenemase Gene ◽  
The Impact

ABSTRACT Carbapenem-resistant Enterobacteriaceae (CRE) represent a health threat, but effective control interventions remain unclear. Hospital wastewater sites are increasingly being highlighted as important potential reservoirs. We investigated a large Klebsiella pneumoniae carbapenemase (KPC)-producing Escherichia coli outbreak and wider CRE incidence trends in the Central Manchester University Hospital NHS Foundation Trust (CMFT) (United Kingdom) over 8 years, to determine the impact of infection prevention and control measures. Bacteriology and patient administration data (2009 to 2017) were linked, and a subset of CMFT or regional hospital KPC-producing E. coli isolates (n = 268) were sequenced. Control interventions followed international guidelines and included cohorting, rectal screening (n = 184,539 screens), environmental sampling, enhanced cleaning, and ward closure and plumbing replacement. Segmented regression of time trends for CRE detections was used to evaluate the impact of interventions on CRE incidence. Genomic analysis (n = 268 isolates) identified the spread of a KPC-producing E. coli outbreak clone (strain A, sequence type 216 [ST216]; n = 125) among patients and in the environment, particularly on 2 cardiac wards (wards 3 and 4), despite control measures. ST216 strain A had caused an antecedent outbreak and shared its KPC plasmids with other E. coli lineages and Enterobacteriaceae species. CRE acquisition incidence declined after closure of wards 3 and 4 and plumbing replacement, suggesting an environmental contribution. However, ward 3/ward 4 wastewater sites were rapidly recolonized with CRE and patient CRE acquisitions recurred, albeit at lower rates. Patient relocation and plumbing replacement were associated with control of a clonal KPC-producing E. coli outbreak; however, environmental contamination with CRE and patient CRE acquisitions recurred rapidly following this intervention. The large numbers of cases and the persistence of blaKPC in E. coli, including pathogenic lineages, are of concern.

scholarly journals Restricted Gene Flow among Hospital Subpopulations of Enterococcus faecium

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Rob J. L. Willems ◽  
Janetta Top ◽  
Willem van Schaik ◽  
Helen Leavis ◽  
Marc Bonten ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Enterococcus Faecium ◽  
Population Genetic ◽  
Effective Control ◽  
Phylogenomic Analysis ◽  
Content Type ◽  
Sequence Types ◽  
Insight Into

ABSTRACT Enterococcus faecium has recently emerged as an important multiresistant nosocomial pathogen. Defining population structure in this species is required to provide insight into the existence, distribution, and dynamics of specific multiresistant or pathogenic lineages in particular environments, like the hospital. Here, we probe the population structure of E. faecium using Bayesian-based population genetic modeling implemented in Bayesian Analysis of Population Structure (BAPS) software. The analysis involved 1,720 isolates belonging to 519 sequence types (STs) (491 for E. faecium and 28 for Enterococcus faecalis). E. faecium isolates grouped into 13 BAPS (sub)groups, but the large majority (80%) of nosocomial isolates clustered in two subgroups (2-1 and 3-3). Phylogenetic and eBURST analysis of BAPS groups 2 and 3 confirmed the existence of three separate hospital lineages (17, 18, and 78), highlighting different evolutionary trajectories for BAPS 2-1 (lineage 78) and 3-3 (lineage 17 and lineage 18) isolates. Phylogenomic analysis of 29 E. faecium isolates showed agreement between BAPS assignment of STs and their relative positions in the phylogenetic tree. Odds ratio calculation confirmed the significant association between hospital isolates with BAPS 3-3 and lineages 17, 18, and 78. Admixture analysis showed a scarce number of recombination events between the different BAPS groups. For the E. faecium hospital population, we propose an evolutionary model in which strains with a high propensity to colonize and infect hospitalized patients arise through horizontal gene transfer. Once adapted to the distinct hospital niche, this subpopulation becomes isolated, and recombination with other populations declines. IMPORTANCE Multiresistant Enterococcus faecium has become one of the most important nosocomial pathogens, causing increasing numbers of nosocomial infections worldwide. Here, we used Bayesian population genetic analysis to identify groups of related E. faecium strains and show a significant association of hospital and farm animal isolates to different genetic groups. We also found that hospital isolates could be divided into three lineages originating from sequence types (STs) 17, 18, and 78. We propose that, driven by the selective pressure in hospitals, the three hospital lineages have arisen through horizontal gene transfer, but once adapted to the distinct pathogenic niche, this population has become isolated and recombination with other populations declines. Elucidation of the population structure is a prerequisite for effective control of multiresistant E. faecium since it provides insight into the processes that have led to the progressive change of E. faecium from an innocent commensal to a multiresistant hospital-adapted pathogen.

scholarly journals Reservoir Targeted Vaccine for Lyme Borreliosis Induces a Yearlong, Neutralizing Antibody Response to OspA in White-Footed Mice

2011 ◽  
Vol 18 (11) ◽  
pp. 1809-1816 ◽  
Author(s):  
Luciana Meirelles Richer ◽  
Miguel Aroso ◽  
Tania Contente-Cuomo ◽  
Larisa Ivanova ◽  
Maria Gomes-Solecki
Keyword(s):  
Immune Response ◽  
Lyme Disease ◽  
Protein A ◽  
Surface Protein ◽  
Neutralizing Antibody ◽  
Control Measures ◽  
Content Type ◽  
Wildlife Reservoirs ◽  
Minimum Number ◽  
Enzootic Cycle

ABSTRACTLyme disease is caused by the spirocheteBorrelia burgdorferi. The enzootic cycle of this pathogen requires thatIxodesspp. acquireB. burgdorferifrom infected wildlife reservoirs and transmit it to other uninfected wildlife. At present, there are no effective measures to controlB. burgdorferi; there is no human vaccine available, and existing vector control measures are generally not acceptable to the public. However, ifB. burgdorfericould be eliminated from its reservoir hosts or from the ticks that feed on them, the enzootic cycle would be broken, and the incidence of Lyme disease would decrease. We developed OspA-RTV, a reservoir targeted bait vaccine (RTV) based on the immunogenic outer surface protein A (OspA) ofB. burgdorferiaimed at breaking the natural cycle of this spirochete. White-footed mice, the major reservoir species for this spirochete in nature developed a systemic OspA-specific IgG response as a result of ingestion of the bait formulation. This immune response protected white-footed mice againstB. burgdorferiinfection upon tick challenge and clearedB. burgdorferifrom the tick vector. In performing extensive studies to optimize the OspA-RTV for field deployment, we determined that mice that consumed the vaccine over periods of 1 or 4 months developed a yearlong, neutralizing anti-OspA systemic IgG response. Furthermore, we defined the minimum number of OspA-RTV units needed to induce a protective immune response.

scholarly journals A Monomorphic Haplotype of Chromosome Ia Is Associated with Widespread Success in Clonal and Nonclonal Populations of Toxoplasma gondii

mBio ◽  
2011 ◽  
Vol 2 (6) ◽  
Author(s):  
Asis Khan ◽  
Natalie Miller ◽  
David S. Roos ◽  
J. P. Dubey ◽  
Daniel Ajzenberg ◽  
...  
Keyword(s):  
Population Structure ◽  
Toxoplasma Gondii ◽  
North America ◽  
South America ◽  
Clonal Expansion ◽  
Content Type ◽  
The North ◽  
Fitness Advantage ◽  
Sexual Recombination ◽  
Geographic Regions

ABSTRACT Toxoplasma gondii is a common parasite of animals that also causes a zoonotic infection in humans. Previous studies have revealed a strongly clonal population structure that is shared between North America and Europe, while South American strains show greater genetic diversity and evidence of sexual recombination. The common inheritance of a monomorphic version of chromosome Ia (referred to as ChrIa*) among three clonal lineages from North America and Europe suggests that inheritance of this chromosome might underlie their recent clonal expansion. To further examine the diversity and distribution of ChrIa, we have analyzed additional strains with greater geographic diversity. Our findings reveal that the same haplotype of ChrIa* is found in the clonal lineages from North America and Europe and in older lineages in South America, where sexual recombination is more common. Although lineages from all three continents harbor the same conserved ChrIa* haplotype, strains from North America and Europe are genetically separate from those in South America, and these respective geographic regions show limited evidence of recent mixing. Genome-wide, array-based profiling of polymorphisms provided evidence for an ancestral flow from particular older southern lineages that gave rise to the clonal lineages now dominant in the north. Collectively, these data indicate that ChrIa* is widespread among nonclonal strains in South America and has more recently been associated with clonal expansion of specific lineages in North America and Europe. These findings have significant implications for the spread of genetic loci influencing transmission and virulence in pathogen populations. IMPORTANCE Understanding parasite population structure is important for evaluating the potential spread of pathogenicity determinants between different geographic regions. Examining the genetic makeup of different isolates of Toxoplasma gondii from around the world revealed that chromosome Ia is highly homogeneous among lineages that predominate on different continents and within genomes that were otherwise quite divergent. This pattern of recent shared ancestry is highly unusual and suggests that some gene(s) found on this chromosome imparts an unusual fitness advantage that has resulted in its recent spread. Although the basis for the conservation of this particularly homogeneous chromosome is unknown, it may have implications for the transmission of infection and spread of human disease.

scholarly journals An In Vitro Pipeline for Screening and Selection of Citrus-Associated Microbiota with Potential Anti-“Candidatus Liberibacter asiaticus” Properties

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Alex Blacutt ◽  
Nichole Ginnan ◽  
Tyler Dang ◽  
Sohrab Bodaghi ◽  
Georgios Vidalakis ◽  
...  
Keyword(s):  
Natural Products ◽  
Inhibitory Activity ◽  
Cladosporium Cladosporioides ◽  
Control Measures ◽  
Effective Control ◽  
Content Type ◽  
Agar Diffusion ◽  
Liberibacter Asiaticus ◽  
Citrus Disease

ABSTRACT Huanglongbing (HLB) is a destructive citrus disease that is lethal to all commercial citrus plants, making it the most serious citrus disease and one of the most serious plant diseases. Because of the severity of HLB and the paucity of effective control measures, we structured this study to encompass the entirety of the citrus microbiome and the chemistries associated with that microbial community. We describe the spatial niche diversity of bacteria and fungi associated with citrus roots, stems, and leaves using traditional microbial culturing integrated with culture-independent methods. Using the culturable sector of the citrus microbiome, we created a microbial repository using a high-throughput bulk culturing and microbial identification pipeline. We integrated an in vitro agar diffusion inhibition bioassay into our culturing pipeline that queried the repository for antimicrobial activity against Liberibacter crescens, a culturable surrogate for the nonculturable “Candidatus Liberibacter asiaticus” bacterium associated with HLB. We identified microbes with robust inhibitory activity against L. crescens that include the fungi Cladosporium cladosporioides and Epicoccum nigrum and bacterial species of Pantoea, Bacillus, and Curtobacterium. Purified bioactive natural products with anti-“Ca. Liberibacter asiaticus” activity were identified from the fungus C. cladosporioides. Bioassay-guided fractionation of an organic extract of C. cladosporioides yielded the natural products cladosporols A, C, and D as the active agents against L. crescens. This work serves as a foundation for unraveling the complex chemistries associated with the citrus microbiome to begin to understand the functional roles of members of the microbiome, with the long-term goal of developing anti-“Ca. Liberibacter asiaticus” bioinoculants that thrive in the citrus holosystem. IMPORTANCE Globally, citrus is threatened by huanglongbing (HLB), and the lack of effective control measures is a major concern of farmers, markets, and consumers. There is compelling evidence that plant health is a function of the activities of the plant's associated microbiome. Using Liberibacter crescens, a culturable surrogate for the unculturable HLB-associated bacterium “Candidatus Liberibacter asiaticus,” we tested the hypothesis that members of the citrus microbiome produce potential anti-“Ca. Liberibacter asiaticus” natural products with potential anti-“Ca. Liberibacter asiaticus” activity. A subset of isolates obtained from the microbiome inhibited L. crescens growth in an agar diffusion inhibition assay. Further fractionation experiments linked the inhibitory activity of the fungus Cladosporium cladosporioides to the fungus-produced natural products cladosporols A, C, and D, demonstrating dose-dependent antagonism to L. crescens.

scholarly journals Global population genomic analysis of Mycoplasma bovis isolates reveals transcontinental variations and potential virulence genes

2020 ◽  
Author(s):  
Roshan Kumar ◽  
Karen Register ◽  
Jane Christopher-Hennings ◽  
Paolo Moroni ◽  
Gloria Gioa ◽  
...  
Keyword(s):  
Population Structure ◽  
North America ◽  
Large Scale ◽  
Vaccine Development ◽  
Population Analysis ◽  
Genomic Analysis ◽  
Control Measures ◽  
Mycoplasma Bovis ◽  
Whole Genome ◽  
Host Association

AbstractAmong more than twenty species belonging to the class Mollecutes, Mycoplasma bovis is the most common cause of bovine mycoplasmosis in North America and Europe. Bovine mycoplasmosis causes significant economic loss in the cattle industry. The number of M. bovis positive herds has recently increased in North America and Europe. Since antibiotic treatment is ineffective and no efficient vaccine is available, M. bovis-induced mycoplasmosis is primarily controlled by herd management measures such as the restriction of moving infected animals out of the herds and culling of infected animals or shedders. To better understand the population structure and genomic factors that may contribute to its transmission, we sequenced 147 M. bovis strains isolated from four different countries and hosts, primarily cattle. We performed a large-scale comparative analysis of M. bovis genomes by integrating 104 publicly available genomes and our dataset (251 total genomes). A whole genome-single nucleotide polymorphism (SNP)-based phylogeny revealed that M. bovis population structure is composed of five clades with one of the isolates clustering with the outgroup M. agalactiae. These isolates were found to cluster with those from Canada, Israel, Lithuania, and Switzerland, suggesting trans-continental transmission of the strains. We also validated a previous report suggesting minimum divergence in isolates of Australian origin, which grouped within a single clade along with strains from China and Israel. However, no observable pattern of host association in M. bovis genomes was found in this study. Our comparative genome analysis also revealed that M. bovis has an open pangenome with a large breadth of unexplored diversity of genes. Analysis of vsp gene-host association revealed a single vsp significantly associated with bovine isolates that may be targeted for diagnostics or vaccine development. Our study also found that M. bovis genome harbors a large number of IS elements, including a novel 1624 bp IS element, and ISMbov9. Collectively, the genome data and the whole genome-based population analysis in this study may help to develop control measures to reduce the incidence of M. bovis-induced mycoplasmosis in cattle and/or to identify candidate genes for vaccine development.

scholarly journals Six decades of infectious bursal disease in poultry: The journey so far and challenges ahead

2021 ◽  
Vol 19 (3) ◽  
pp. 150-173
Author(s):  
N. Lawal ◽  
M.B. Bello
Keyword(s):  
Viral Vectors ◽  
Management Practices ◽  
Protein Structures ◽  
Control Measures ◽  
Infectious Bursal Disease ◽  
Effective Control ◽  
Poultry Production ◽  
Genetic Characteristics ◽  
Bursal Disease ◽  
Serotype 1

Despite six decades of concerted efforts, Infectious bursal disease (IBD) still remains a major threat to the poultry industry worldwide. Most importantly, the emergence of variant and very virulent strains of infectious bursal disease virus (IBDV) has dramatically changed the epidemiology of the disease, thus resulting in the renewed efforts in the search for effective control measures. Currently, live attenuated, inactivated, and immune-complex vaccines are among the immune-therapeutic approaches employed for the control of IBD in the field alongside adequate biosecurity, albeit with various degrees of success and limitations. Progress in genetic engineering has allowed the generation of reverse genetic IBDV mutants, recombinant live viral vectors expressing the IBDV VP2 immunodominant protein, intra-serotypic recombinant IBDV viral-like particle co-expressing the outer capsid protein structures derived from 2 or more serotype 1 strains or the incorporation of either VP2 or VP2-4-3 polyprotein sequences alongside molecular adjuvants that can be used as IBD vaccine candidates to elicit an immune response. However, despite these advances, outbreaks are still reported even in flocks that have up to date vaccination records and somewhat excellent management practices. This paper reviews aspect of genetic characteristics of IBDV and reflects on the progress and future challenges in providing effective IBD vaccine to achieve effective control of both classical and very-virulent IBDV serotypes that constitute a major devastation to poultry production and health.

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