9 results on '"Robinson, D. Ashley"'
Search Results
2. Clones of Streptococcus pneumoniae Isolated from Nasopharyngeal Carriage and Invasive Disease in Young Children in Central Tennessee
- Author
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Robinson, D. Ashley, Edwards, Kathryn M., Waites, Ken B., Briles, David E., Crain, Marilyn J., and Hollingshead, Susan K.
- Published
- 2001
3. Molecular Characterization of a Globally Distributed Lineage of Serotype 12F Streptococcus pneumoniae Causing Invasive Disease
- Author
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Robinson, D. Ashley, Turner, J. Scott, Facklam, Richard R., Parkinson, Alan J., Breiman, Robert F., Gratten, Mike, Steinhoff, Mark C., Hollingshead, Susan K., Briles, David E., and Crain, Marilyn J.
- Published
- 1999
4. Methicillin-Resistant Staphylococcus aureus Sequence Type 239-III, Ohio, USA, 2007–20091
- Author
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Wang, Shu-Hua, Khan, Yosef, Hines, Lisa, Mediavilla, José R., Zhang, Liangfen, Chen, Liang, Hoet, Armando, Bannerman, Tammy, Pancholi, Preeti, Robinson, D. Ashley, Kreiswirth, Barry N., and Stevenson, Kurt B.
- Subjects
Male ,sequence type ,Epidemiology ,Human pathogen ,MRSA ,medicine.disease_cause ,Genotype ,CME ,bacteria ,Aged, 80 and over ,Cross Infection ,Transmission (medicine) ,Portuguese clone ,Middle Aged ,Staphylococcal Infections ,MRSA ST239-III ,Anti-Bacterial Agents ,Bacterial Typing Techniques ,Brazilian clone ,Infectious Diseases ,Staphylococcus aureus ,Female ,Microbiology (medical) ,Adult ,Methicillin-Resistant Staphylococcus aureus ,Adolescent ,Virulence ,Microbial Sensitivity Tests ,Biology ,Staphylococcal infections ,Article ,virulent clones ,Microbiology ,Catheterization ,Young Adult ,Renal Dialysis ,medicine ,Humans ,Ohio ,Aged ,Research ,Outbreak ,bacterial infections and mycoses ,medicine.disease ,Methicillin-resistant Staphylococcus aureus ,Virology ,Respiration, Artificial ,United States ,Molecular Typing - Abstract
Identification of virulent strains emphasizes the need for molecular surveillance., Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen that has diverse molecular heterogeneity. Most MRSA strains in the United States are pulsed-field gel electrophoresis USA100 sequence type (ST) 5 and USA300 ST8. Infections with MRSA ST239-III are common and found during health care–associated outbreaks. However, this strain has been rarely reported in the United States. As part of a study supported by the Prevention Epicenter Program of the Centers for Disease Control and Prevention (Atlanta, GA, USA), which evaluated transmission of MRSA among hospitals in Ohio, molecular typing identified 78 (6%) of 1,286 patients with MRSA ST239-III infections. Ninety-five percent (74/78) of these infections were health care associated, and 65% (51/78) of patients had histories of invasive device use. The crude case-fatality rate was 22% (17/78). Identification of these strains, which belong to a virulent clonal group, emphasizes the need for molecular surveillance.
- Published
- 2012
5. Parallel Epidemics of Community-Associated Methicillin-Resistant Staphylococcus aureus USA300 Infection in North and South America.
- Author
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Planet, Paul J., Diaz, Lorena, Kolokotronis, Sergios-Orestis, Narechania, Apurva, Reyes, Jinnethe, Xing, Galen, Rincon, Sandra, Smith, Hannah, Panesso, Diana, Ryan, Chanelle, Smith, Dylan P., Guzman, Manuel, Zurita, Jeannete, Sebra, Robert, Deikus, Gintaras, Nolan, Rathel L., Tenover, Fred C., Weinstock, George M., Robinson, D. Ashley, and Arias, Cesar A.
- Subjects
METHICILLIN-resistant staphylococcus aureus ,EPIDEMICS ,BIOLOGICAL divergence ,PHYLOGENY ,ARGININE ,NUCLEOTIDE sequencing ,DRUG resistance in microorganisms ,SINGLE nucleotide polymorphisms ,MICROBIAL genetics ,EPIDEMIOLOGY ,GENETIC techniques ,GENOMES ,MOLECULAR epidemiology ,RESEARCH funding ,STAPHYLOCOCCAL diseases ,COMMUNITY-acquired infections ,SEQUENCE analysis ,GENOTYPES - Abstract
Background: The community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) epidemic in the United States is attributed to the spread of the USA300 clone. An epidemic of CA-MRSA closely related to USA300 has occurred in northern South America (USA300 Latin-American variant, USA300-LV). Using phylogenomic analysis, we aimed to understand the relationships between these 2 epidemics.Methods: We sequenced the genomes of 51 MRSA clinical isolates collected between 1999 and 2012 from the United States, Colombia, Venezuela, and Ecuador. Phylogenetic analysis was used to infer the relationships and times since the divergence of the major clades.Results: Phylogenetic analyses revealed 2 dominant clades that segregated by geographical region, had a putative common ancestor in 1975, and originated in 1989, in North America, and in 1985, in South America. Emergence of these parallel epidemics coincides with the independent acquisition of the arginine catabolic mobile element (ACME) in North American isolates and a novel copper and mercury resistance (COMER) mobile element in South American isolates.Conclusions: Our results reveal the existence of 2 parallel USA300 epidemics that shared a recent common ancestor. The simultaneous rapid dissemination of these 2 epidemic clades suggests the presence of shared, potentially convergent adaptations that enhance fitness and ability to spread. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
6. Multilocus Sequence Typing and Further Genetic Characterization of the Enigmatic Pathogen, Staphylococcus hominis.
- Author
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Zhang, Liangfen, Thomas, Jonathan C., Miragaia, Maria, Bouchami, Ons, Chaves, Fernando, d’Azevedo, Pedro A., Aanensen, David M., de Lencastre, Herminia, Gray, Barry M., and Robinson, D. Ashley
- Subjects
SUBSPECIES ,EPIDEMIOLOGY ,COMMUNICABLE diseases ,BACTERIOLOGY ,EMERGING infectious diseases ,STAPHYLOCOCCAL diseases - Abstract
Staphylococcus hominis is a commensal resident of human skin and an opportunistic pathogen. The species is subdivided into two subspecies, S. hominis subsp. hominis and S. hominis subsp. novobiosepticus, which are difficult to distinguish. To investigate the evolution and epidemiology of S. hominis, a total of 108 isolates collected from 10 countries over 40 years were characterized by classical phenotypic methods and genetic methods. One nonsynonymous mutation in gyrB, scored with a novel SNP typing assay, had a perfect association with the novobiocin-resistant phenotype. A multilocus sequence typing (MLST) scheme was developed from six housekeeping gene fragments, and revealed relatively high levels of genetic diversity and a significant impact of recombination on S. hominis population structure. Among the 40 sequence types (STs) identified by MLST, three STs (ST2, ST16 and ST23) were S. hominis subsp. novobiosepticus, and they distinguished between isolates from different outbreaks, whereas 37 other STs were S. hominis subsp. hominis, one of which was widely disseminated (ST1). A modified PCR assay was developed to detect the presence of ccrAB4 from the SCCmec genetic element. S. hominis subsp. novobiosepticus isolates were oxacillin-resistant and carriers of specific components of SCCmec (mecA class A, ccrAB3, ccrAB4, ccrC), whereas S. hominis subsp. hominis included both oxacillin-sensitive and -resistant isolates and a more diverse array of SCCmec components. Surprisingly, phylogenetic analyses indicated that S. hominis subsp. novobiosepticus may be a polyphyletic and, hence, artificial taxon. In summary, these results revealed the genetic diversity of S. hominis, the identities of outbreak-causing clones, and the evolutionary relationships between subspecies and clones. The pathogenic lifestyle attributed to S. hominis subsp. novobiosepticus may have originated on more than one occasion. [ABSTRACT FROM AUTHOR]
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- 2013
- Full Text
- View/download PDF
7. Molecular tracing of the emergence, adaptation, and transmission of hospital-associated methicillin-resistant Staphylococcus aureus.
- Author
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McAdam, Paul R., Templeton, Kate E., Edwards, Giles F., Holden, Matthew T. G., Fei, Edward J., Aanensen, David M., Bargawi, Hiba J. A., Spratt, Brian G., Bentley, Stephen D., Parkhil, Julian, Enright, Mark C., Holmes, Anne, Girvan, E. Kirsty, Godfrey, Paul A., Feldgarden, Michael, Kearns, Angela M., Rambau, Andrew, Robinson, D. Ashley, and Fitzgerald, J. Ross
- Subjects
METHICILLIN-resistant staphylococcus aureus ,PHYLOGENY ,PANDEMICS ,GENETIC mutation ,PHYLOGEOGRAPHY ,MEDICAL care - Abstract
Hospital-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a global health burden dominated by a small number of bacterial clones. The pandemic EMRSA-16 clone (ST36-II) has been widespread in UK hospitals for 20 y, but its evolutionary origin and the molecular basis for its hospital association are unclear. We carried out a Bayesian phylogenetic reconstruction on the basis of the genome sequences of 87 S. aureus isolates including 60 EMRSA-16 and 27 additional clonal complex 30 (CC30) isolates, collected from patients in three continents over a 53-y period. The three major pandemic clones to originate from the CC30 lineage, including phage type 80/81, Southwest Pacific, and EMRSA-16, shared a most recent common ancestor that existed over 100 y ago, whereas the hospital-associated EMRSA-16 clone is estimated to have emerged about 35 y ago. Our CC30 genome-wide analysis revealed striking molecular correlates of hospital- or community-associated pandemics represented by mobile genetic elements and nonsynonymous mutations affecting antibiotic resistance and virulence. Importantly, phylogeographic analysis indicates that EMRSA-16 spread within the United Kingdom by transmission from hospitals in large population centers in London and Glasgow to regional health-care settings, implicating patient referrals as an important cause of nationwide transmission. Taken together, the high-resolution phylogenomic approach used resulted in a unique understanding of the emergence and transmission of a major MRSA clone and provided molecular correlates of its hospital adaptation. Similar approaches for hospitalassociated clones of other bacterial pathogens may inform appropriate measures for controlling their intra- and interhospital spread. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
8. Population Structure of a Hybrid Clonal Group of Methicillin-Resistant Staphylococcus aureus, ST239-MRSA-III.
- Author
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Smyth, Davida S., McDougal, Linda K., Gran, Frode W., Manoharan, Anand, Enright, Mark C., Jae-Hoon Song, de Lencastre, Herminia, and Robinson, D. Ashley
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STAPHYLOCOCCUS aureus ,DRUG resistance ,METHICILLIN resistance ,EPIDEMICS ,HUMAN genetic variation ,POPULATION genetics ,STAPHYLOCOCCUS ,PHARMACOLOGY ,EPIDEMIOLOGY - Abstract
The methicillin-resistant Staphylococcus aureus (MRSA) clonal group known as ST239-MRSA-III is notable for its hybrid origin and for causing sustained hospital epidemics worldwide since the late 1970s. We studied the population structure of this MRSA clonal group using a sample of 111 isolates that were collected over 34 years from 29 countries. Genetic variation was assessed using typing methods and novel ascertainment methods, resulting in approximately 15 kb of sequence from 32 loci for all isolates. A single most parsimonious tree, free of homoplasy, partitioned 28 haplotypes into geographicallyassociated clades, including prominent European, Asian, and South American clades. The rate of evolution was estimated to be approximately 100× faster than standard estimates for bacteria, and dated the most recent common ancestor of these isolates to the mid-20th century. Associations were discovered between the ST239 phylogeny and the ccrB and dru loci of the methicillin resistance genetic element, SCCmec type III, but not with the accessory components of the element that are targeted by multiplex PCR subtyping tools. In summary, the evolutionary history of ST239 can be characterized by rapid clonal diversification that has left strong evidence of geographic and temporal population structure. SCCmec type III has remained linked to the ST239 chromosome during clonal diversification, but it has undergone homoplasious losses of accessory components. These results provide a population genetics framework for the precise identification of emerging ST239 variants, and invite a re-evaluation of the markers used for subtyping SCCmec. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
9. Multilocus Sequence Typing and Further Genetic Characterization of the Enigmatic Pathogen, Staphylococcus hominis.
- Author
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Zhang, Liangfen, Thomas, Jonathan C., Miragaia, Maria, Bouchami, Ons, Chaves, Fernando, d’Azevedo, Pedro A., Aanensen, David M., de Lencastre, Herminia, Gray, Barry M., and Robinson, D. Ashley
- Subjects
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SUBSPECIES , *EPIDEMIOLOGY , *COMMUNICABLE diseases , *BACTERIOLOGY , *EMERGING infectious diseases , *STAPHYLOCOCCAL diseases - Abstract
Staphylococcus hominis is a commensal resident of human skin and an opportunistic pathogen. The species is subdivided into two subspecies, S. hominis subsp. hominis and S. hominis subsp. novobiosepticus, which are difficult to distinguish. To investigate the evolution and epidemiology of S. hominis, a total of 108 isolates collected from 10 countries over 40 years were characterized by classical phenotypic methods and genetic methods. One nonsynonymous mutation in gyrB, scored with a novel SNP typing assay, had a perfect association with the novobiocin-resistant phenotype. A multilocus sequence typing (MLST) scheme was developed from six housekeeping gene fragments, and revealed relatively high levels of genetic diversity and a significant impact of recombination on S. hominis population structure. Among the 40 sequence types (STs) identified by MLST, three STs (ST2, ST16 and ST23) were S. hominis subsp. novobiosepticus, and they distinguished between isolates from different outbreaks, whereas 37 other STs were S. hominis subsp. hominis, one of which was widely disseminated (ST1). A modified PCR assay was developed to detect the presence of ccrAB4 from the SCCmec genetic element. S. hominis subsp. novobiosepticus isolates were oxacillin-resistant and carriers of specific components of SCCmec (mecA class A, ccrAB3, ccrAB4, ccrC), whereas S. hominis subsp. hominis included both oxacillin-sensitive and -resistant isolates and a more diverse array of SCCmec components. Surprisingly, phylogenetic analyses indicated that S. hominis subsp. novobiosepticus may be a polyphyletic and, hence, artificial taxon. In summary, these results revealed the genetic diversity of S. hominis, the identities of outbreak-causing clones, and the evolutionary relationships between subspecies and clones. The pathogenic lifestyle attributed to S. hominis subsp. novobiosepticus may have originated on more than one occasion. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
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