Molecular patterns of community-acquired methicillin-resistant Staphylococcus aureus strains in Malaysian carriers

Abstract number: 1733_1079

Neela V., Mariana N., Zamberi S.

Objective: The ultimate aim of the study is to perform molecular characterisation of methicillin-resistant Staphylococcus aureus (CA-MRSA) strains to understand the drug resistance and virulent properties. Knowledge on the molecular properties is important for the correct treatment and efficient management of CA-MRSA strains. Specific objectives are to determine the molecular patterns of local strains focusing on the SCCmec (Staphylococcal cassette chromosome mec element) types, presence of Panton-Valentine leukocidin (PVL) gene and the strain types (ST).

Methods: Twenty-two S. aureus isolates isolated from 100 university students screened during November 2005 to February 2006 were identified as MRSA. Phenotypic confirmation was carried out by antibiotic susceptibility test against various antibiotics (vancomycin, gentamicin, erythromycin, and mupirocin). All isolates were confirmed genotypically as MRSA using mecA primers. Each isolate was further investigated for CA-MRSA by SCCmec typing using published primers. Presence of PVL genes in all CA-MRSA isolates was also determined. Multi locus sequence typing (MLST) analysis of each CA-MRSA isolates was carried out to identify the strain type (ST).

Results: Of the twenty-two MRSA isolates, three isolates were identified as CA-MRSA. The molecular pattern of the three CA-MRSA isolates analysed by SCCmec typing revealed two SCCmec types. Two isolates were positive for SCCmec type V and one isolate was positive for SCCmec type IVa. The two SCCmec type V isolates were sensitive to non b-lactams while the SCCmec type IVa positive isolate was resistant to non b-lactam antibiotics and also carried the PVL gene. Positive signal for PVL gene was not observed in the SCCmec type V isolates. MLST analysis of the three CA-MRSA strains showed the strain type for SCCmec type 1Va isolate as ST-80, while SCCmec type V isolates belonged to ST-34.

Conclusion: The molecular patterns of the local CA-MRSA strains studied give valuable information on the SCCmec type, virulent gene carried and the clonal type circulating in local communities. The molecular information of the local strains could be very useful in prescribing correct antibiotics enhancing appropriate treatment and successful management of the CA-MRSA strains in Malaysia.

Session Details

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