Variable number tandem repeat assay for typing meticillin-resistant Staphylococcus aureus
Abstract number: P937
Rivero-Pérez B., Pérez-Roth E., Alcoba-Flórez J., Laich F., Espinoza-Jiménez A., Méndez-Álvarez S.
In the work with pathogen microorganisms, the knowledge of their DNA fingerprints is necessary for the delineation of outbreaks of infections disease and for the global tracking of them. For these reasons, on the last decades an intense search of methods to improve this way has taken place. Variable Number Tandem Repeat Assay (MLVA) was described for the first time in 1995 as a new typing method for Haemophilus influenzae. Later, in 2003 Sabat et al. introduced it for the study of Staphylococcus aureus. However, the usefulness of this technique is still an opened question.
Objectives: The aim of our study has been to determine the utility of MLVA for typing S. aureus isolates and to compare the results obtained with those generated by means of the Pulsed-Field Gel Electrophoresis (PFGE).
Methods: A multiplex PCR assay, optimised by us, containing primers to simultaneously amplify clfA, clfB, sdrCDE, spa and sspa loci, and PFGE macrorrestriction patterns analysis were applied to a group of meticillin-resistant S. aureus (MRSA), collected since 2002 to 2006. The results obtained by both approaches were compared by means of the power of discrimination of each of them.
Results: All MRSA isolates were typeable by MLVA, being grouped in 23 types, according to the criteria established by Sabat et al. (2003), whereas the PFGE assay distinguished 17 types according to the criteria established by Tennover et al. (1995). As a general rule, within each pulsed-field type, a majority MLVA pattern and others that had one band change with this were noticed.
Conclusion: MLVA is a reliable technique, with a high power to discriminate MRSA isolates. This capacity can be used to perform a local characterisation of MRSA collections. MLVA patterns seem to belong with PFGE types, whenever we consider subtypes (one band different of the majority pattern) inside MLVA types.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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