Use of Oligoarrays for Characterization of Community-Onset Methicillin-Resistant Staphylococcus aureus

Abstract

Until recently, methicillin-resistant Staphylococcus aureus (MRSA) was considered the prototype of a hospital-acquired bacterial pathogen. However, recent reports have shown that MRSA has now emerged in the community. Characterization of specific markers for distinguishing the origin of isolates could contribute to improved knowledge of MRSA epidemiology. The release of whole-genome sequences of hospital-and community-acquired S. aureus strains allowed the development of whole-genome content analysis techniques, including microarrays. We developed a microarray composed of 8,191 open reading frame-specific oligonucleotides covering >99% of the four sequenced S. aureus genomes (N315, Mu50, MW2, and COL) to evaluate gene contents of hospital-and community-onset S. aureus strains. In parallel, pulsed-field gel electrophoresis, variable number of tandem repeats, antibiogram, staphylococcal cassette chromosome-mec element typing, and presence of the Panton-Valentine leukocidin gene were evaluated in a collection of 15 clinical isolates. Clusters obtained with microarrays showed a high degree of similarity with those obtained by pulsed-field gel electrophoresis or variable number of tandem repeats. Clusters clearly segregated hospital-onset strains from community-onset strains. Moreover, the microarray approach allowed definition of novel marker genes and chromosomal regions specific for given groups of isolates, thus providing better discrimination and additional information compared to pulsed-field gel electrophoresis and variable number of tandem repeats. Finally, the comparative genome hybridization approach unraveled the occurrence of multiple horizontal transfer events leading to community-onset MRSA as well as the need for a specific genetic background in recipient strains for both the acquisition and the stability of the mec element.

Mupirocin-Induced Mutations in ileS in Various Genetic Backgrounds of Methicillin-Resistant Staphylococcus aureus

“…Strains were genotyped and characterized as previously described by using a multilocus variable-number tandem-repeat assay (13,14) and multilocus sequence typing (15).…”

High-throughput typing of Staphylococcus aureus by amplified fragment length polymorphism (AFLP) or multi-locus variable number of tandem repeat analysis (MLVA) reveals consistent strain relatedness

“…In addition, multiple-locus variable number of tandem repeat analysis (MLVA) was performed for all isolates [12,13]. In short, repetitive DNA from the V8 serine protease (sspA), protein A (spa), Ser-Asp-rich fibrinogen-binding protein (sdrCDE), clumping factor B (clfB), clumping factor A (clfA), fibronectin-binding protein (fnBP), collagen adhesion A (cna), methicillin-resistant surface protein (pls), and cell wall surface-anchored protein (sas) genes were amplified in a single multiplex PCR, also including the nonrepeat containing methicillin resistance (mecA) gene.…”

Validation of Virulence and Epidemiology DNA Microarray for Identification and Characterization of Staphylococcus aureus Isolates

“…The VirEp microarray could be refined by the inclusion of additional selected targets that could improve the discriminatory power of the microarray. A recent study has demonstrated the potentially superior resolving power of microarrays compared to PFGE and multilocus sequence typing for typing of CA-MRSA isolates (12).…”