Panton-Valentine leukocidin genes in Staphylococcus aureus.
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Adolescent↗
Biomedical subjects
Justine K Peeters
Publications and source records attributed to Justine K Peeters.
Host- and tissue-specific pathogenic traits of Staphylococcus aureus.
Comparative genomics were used to assess genetic differences between Staphylococcus aureus strains derived from infected animals versus colonized or infected humans. A total of 77 veterinary isolates were genetically characterized by high-throughput amplified fragment length polymorphism (AFLP). Bacterial genotypes were introduced in a large AFLP database containing similar information for 1,056 human S. aureus strains. All S. aureus strains isolated from animals in close contact with humans (e.g., pet animals) were predominantly classified in one of the five main clusters of the AFLP database (cluster I). In essence, mastitis-associated strains from animals were categorized separately (cluster IVa) and cosegregated with bacteremia-associated strains from humans. Distribution of only 2 out of 10 different virulence genes differed across the clusters. The gene encoding the toxic shock syndrome protein (tst) was more often encountered among veterinary strains (P < 0.0001) and even more in the mastitis-related strains (P<0.0001) compared to human isolate results. The gene encoding the collagen binding protein (cna) was rarely detected among invasive human strains. The virulence potential, as indicated by the number of virulence genes per strain, did not differ significantly between the human- and animal-related strains. Our data show that invasive infections in pets and humans are usually due to S. aureus strains with the same genetic background. Mastitis-associated S. aureus isolated in diverse farm animal species form a distinct genetic cluster, characterized by an overrepresentation of the toxic shock syndrome toxin superantigen-encoding gene.
Adhesins, Bacterial↗
Growing applications and advancements in microarray technology and analysis tools.
In today's field of genomics, traditional gene-by-gene approach is not adequate to meet the demand of processing information generated from mapping the complex biology of the human genome. More global views of analyzing the magnitude of information are necessary, such as with microarrays. Microarray technology today is rapidly uncovering broad patterns of genetic activity and showing insight into gene functions, processes, and pathways. With the growing technology, imminent knowledge is being generated looking into transcriptional processes and biological mechanisms from many different organisms and phylogeny. Many tools are being developed to assist with the analysis of such high-throughput data, many applications are being utilized by this technology, and the field is growing and expanding rapidly to accommodate the expanding genomics era.
Algorithms↗
Natural population dynamics and expansion of pathogenic clones of Staphylococcus aureus.
The population structure of Staphylococcus aureus carried by healthy humans was determined using a large strain collection of nonclinical origin (n = 829). High-throughput amplified fragment length polymorphism (AFLP) analysis revealed 3 major and 2 minor genetic clusters of S. aureus, which were corroborated by multilocus sequence typing. Major AFLP cluster I comprised 44.4% of the carriage isolates and showed additional heterogeneity whereas major AFLP groups II and III presented 2 homogeneous clusters, including 47.3% of all carriage isolates. Coanalysis of invasive S. aureus strains and epidemic methicillin-resistant S. aureus (MRSA) revealed that all major clusters contained invasive and multiresistant isolates. However, clusters and subclusters with overrepresentation of invasive isolates were also identified. Bacteremia in elderly adults, for instance, was caused by a IVa cluster-derived strain significantly more often than by strains from other AFLP clusters. Furthermore, expansion of multiresistant clones or clones associated with skin disease (impetigo) was detected, which suggests that epidemic potential is present in pathogenic strains of S. aureus. In addition, the virulence gene encoding Panton-Valentine leukocidin was significantly enriched in S. aureus strains causing abscesses and arthritis in comparison with the carriage group. We provide evidence that essentially any S. aureus genotype carried by humans can transform into a life-threatening human pathogen but that certain clones are more virulent than others.
Cloning, Molecular↗