Staphylococcus aureus Genotyping
GenArraytion has developed genotyping arrays based on genetic similarities and differences in the whole genome sequence data from ten Staphylococcus strains. The graphic below shows microarray data from 700 DNA sequences specific for S. aureus strains that provide highly discriminating hybridization-based signatures for high fidelity, treatment-oriented strain discrimination. These results demonstrate that targeted micro-sequencing can provide rapid, informative DNA sequence-based identification and characterization of strains that have not been characterized at the molecular level for rapid, reliable identification of infectious agents and characterization antibiotic susceptibility needed to effectively diagnose and treat local, regional and pandemic infectious disease outbreaks. The approach can be used to detect emerging and genetically engineered threats to public health. Partial matches to common strains may indicate genetic drift, while the appearance of virulence factors and/or antibiotic resistance elements in the absence of markers for organisms known to contain these factors provides an indication of genetic engineering.
Purified DNA from eight Staphylococcus aureus strains was hybridized to the genotyping array (genome sequence is available for only three of the eight, the other five have no prior genetic information). Unique hybridization patterns were obtained for each of the eight strains. A subset of the data are presented in the 3-D plot below the results for sequenced Mu50 (hospital acquired MRSA, vancomycin resistant), USA300 (community acquired MRSA) and the non-sequenced MRSA Strain 328 (ATCC#33591). The location of each data point is a function of its hybridization intensity (indicating presence or absence) from hybridizations with labeled DNA from each of the three target organisms. Sequences present in only one organism fall along the axes. Sequences present in two of the three organisms appear on the walls of the graph. Sequences found in all three strains were removed for clarity of visualization.