High-resolution melting analysis of the spa repeat region of Staphylococcus aureus

Stephens, Alex J., Inman-Bamber, John, Giffard, Philip M., & Huygens, Flavia (2008) High-resolution melting analysis of the spa repeat region of Staphylococcus aureus. Clinical Chemistry, 54(2), pp. 432-436.

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The staphylococcal protein A (spa) locus of Staphylococcus aureus contains a complex repeat structure and is commonly used for single-locus sequence-based genotyping. The real-time PCR platform supports genotyping methods that are single step and closed tube and potentially can be carried out simultaneously with diagnosis. We describe here a method for genotyping S. aureus using high-resolution melting (HRM) analysis of the spa polymorphic region X. METHODS: The conventional PCR spa assay was modified and optimized for the Rotor-Gene 6000 instrument (Corbett Life Science). HRM analysis on the Corbett Rotor-Gene 6000 instrument was used to test 22 known spa sequences obtained from 44 diverse methicillin-resistant S. aureus (MRSA) isolates. Criteria for calling pairs of melting curves "same" or "different" were developed empirically by converting the data to difference graph format with one curve defined as the control. HRM curve comparison between runs was done to determine the portability of the method. The assay performance was assessed by genotyping uncharacterized isolates, carrying out blind trials, and comparing HRM profiles from different runs. RESULTS: HRM analysis of 44 diverse MRSA isolates generated 20 profiles from 22 spa sequence types. The 2 unresolved HRM spa types differed by only 1 bp. Two blind trials demonstrated complete reproducibility with respect to calling the different spa types. Interrun comparisons of HRM curves were successfully developed, indicating the robustness of the method. CONCLUSION: Analysis of the spa locus by HRM resolves spa sequence variants. This single- and closed-tube single-step method for S. aureus genotyping can be easily combined with the interrogation of other genetic markers.

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ID Code: 13696
Item Type: Journal Article
Refereed: Yes
Additional Information: The contents of this journal can be freely accessed online via the journal's web page (see hypertext link) 12 months after publication.
Keywords: infectious diseases, cells and tissue, ihbi, Methicillin Resistance, Polymerase Chain Reaction, Staphylococcal Protein A/, Staphylococcus aureus, genetics, Transition Temperature
DOI: 10.1373/clinchem.2007.093658
ISSN: 1530-8561
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > MICROBIOLOGY (060500) > Infectious Agents (060502)
Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > GENETICS (060400) > Genetics not elsewhere classified (060499)
Divisions: Past > Research Centres > CRC for Diagnostics
Past > QUT Faculties & Divisions > Faculty of Science and Technology
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 2008 American Association for Clinical Chemistry
Deposited On: 10 Jun 2008 00:00
Last Modified: 27 Mar 2015 04:57

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