ORCID Profile
0000-0002-1323-7184
Current Organisations
Universidade Nova de Lisboa Faculdade de Ciências e Tecnologia
,
Instituto de Tecnologia Química e Biológica
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Publisher: Springer Science and Business Media LLC
Date: 28-11-2018
DOI: 10.1038/S41467-018-07368-7
Abstract: Some of the most common infectious diseases are caused by bacteria that naturally colonise humans asymptomatically. Combating these opportunistic pathogens requires an understanding of the traits that differentiate infecting strains from harmless relatives. Staphylococcus epidermidis is carried asymptomatically on the skin and mucous membranes of virtually all humans but is a major cause of nosocomial infection associated with invasive procedures. Here we address the underlying evolutionary mechanisms of opportunistic pathogenicity by combining pangenome-wide association studies and laboratory microbiology to compare S. epidermidis from bloodstream and wound infections and asymptomatic carriage. We identify 61 genes containing infection-associated genetic elements (k-mers) that correlate with in vitro variation in known pathogenicity traits (biofilm formation, cell toxicity, interleukin-8 production, methicillin resistance). Horizontal gene transfer spreads these elements, allowing ergent clones to cause infection. Finally, Random Forest model prediction of disease status (carriage vs. infection) identifies pathogenicity elements in 415 S. epidermidis isolates with 80% accuracy, demonstrating the potential for identifying risk genotypes pre-operatively.
Publisher: Public Library of Science (PLoS)
Date: 10-04-2017
Publisher: Public Library of Science (PLoS)
Date: 15-03-2016
Publisher: American Society for Microbiology
Date: 06-2017
DOI: 10.1128/AAC.02302-16
Abstract: Several lines of evidence indicate that the most primitive staphylococcal species, those of the Staphylococcus sciuri group, were involved in the first stages of evolution of the staphylococcal cassette chromosome mec (SCC mec ), the genetic element carrying the β-lactam resistance gene mecA . However, many steps are still missing from this evolutionary history. In particular, it is not known how mecA was incorporated into the mobile element SCC prior to dissemination among Staphylococcus aureus and other pathogenic staphylococcal species. To gain insights into the possible contribution of several species of the Staphylococcus sciuri group to the assembly of SCC mec , we sequenced the genomes of 106 isolates, comprising S. sciuri ( n = 76), Staphylococcus vitulinus ( n = 18), and Staphylococcus fleurettii ( n = 12) from animal and human sources, and characterized the native location of mecA and the SCC insertion site by using a variety of comparative genomic approaches. Moreover, we performed a single nucleotide polymorphism (SNP) analysis of the genomes in order to understand SCC mec evolution in relation to phylogeny. We found that each of three species of the S. sciuri group contributed to the evolution of SCC mec : S. vitulinus and S. fleurettii contributed to the assembly of the mec complex, and S. sciuri most likely provided the mobile element in which mecA was later incorporated. We hypothesize that an ancestral SCC mec III cassette (an element carried by one of the most epidemic methicillin-resistant S. aureus clones) originated in S. sciuri possibly by a recombination event in a human host or a human-created environment and later was transferred to S. aureus .
Publisher: Public Library of Science (PLoS)
Date: 21-04-2016
Location: Portugal
Location: Portugal
Location: United Kingdom of Great Britain and Northern Ireland
Location: Portugal
Location: No location found
No related grants have been discovered for Maria Miragaia.