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Characterisation of SCCmec type of methicillin-resistant Staphylococcus aureus strains from hospitalised patients admitted in Belgian hospitals

Abstract number: 1733_797

Denis O., Afsar A., De Mendonça R., Deplano A., Nonhoff C., Struelens M.J.

Background: The analysis of SCCmec structure is a key typing tool for classification of clones of methicillin-resistant Staphylococcus aureus. Several strategies based on multiplex PCR have been developed for this purpose. We compared the results of two PCR protocols for SCCmec typing with MRSA strains collected during a national survey in Belgian hospitals in 2005.

Methods: 321 MRSA isolates collected from 116 hospitals were identified by multiplex PCR for mecA, nuc and 16S rDNA genes. SCCmec type was determined by methods described by Oliveira DC (PCR A) (AAC 2002;46:2155) and Zhang K (PCR B) (JCM 2005;43:5026). Discrepant results between two methods were resolved by multiplex PCR for ccr and mec complex determination.

Results: The proportion of non typeable SCCmec was 4% by PCR A and 26% by PCR B (p < 0.001). Only, 210 (64%) isolates had concordant results by both methods and were SCCmec type I (n = 7), type II (n = 44) and type IV (n = 159). 26 isolates were incorrectly typed as SCCmec type I by PCR B but were classified as type IV by PCR A as confirmed by ccr and mec complex analysis. Of 75 isolates which were not typeable by PCR B, 73 were determined of type IV by PCR A, and confirmed by ccr and mec complex determination. Two isolates which were not typeable by PCR A were determined as type IV and type V by PCR B, ccr and mec complex analysis. Ten isolates were untypeable by both methods.

Conclusion: The method of Oliveira et al. showed the best performance for SCCmec typing. However, the presence of untypeable SCCmec variants warrants the combination of methods for SCCmec characterisation.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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