Molecular characterisation of community- and hospital-acquired meticillin-resistant Staphylococcus aureus

Abstract number: P1423

Borghi E., Cainarca M., Grimaldi C., Baccalini R., Lafrancesca M., Scelza G., Morace G.

Objectives: The aim of this work was to investigate the presence of the Panton-Valentine leukocidin (PVL) gene in Community-Acquired Meticillin-Resistant Staphylococcus aureus (CA-MRSA) collected from outpatients in the San Paolo Hospital of Milan from April 2006 to July 2007. Those isolates were also investigated for their SCCmec mobile generic element, coding for meticillin resistance. For comparative purposes we included in this study a matching number of Hospital-Acquired Meticillin-Resistant Staphylococcus aureus (HA-MRSA).

Methods: We collected twenty six CA-MRSA isolates derived from skin and soft tissue specimens as well as respiratory tract secretions or urine; the same number of HA-MRSA strains, coming from patients hospitalised in various wards of the San Paolo Hospital, was collected from blood, respiratory tract secretions or other biological fluids. The DNA extracted was screened by PCR for PVL gene and by multiplex PCR to determine the mec type.

Results: Three MRSA harboured PVL gene, all belonging to CA-MRSA group (11.5%); two of them were SCCmec IV and one SCCmec V; the latter type was confirmed in a subsequent isolate four months later, differing only (data not shown) for the antimicrobial pattern (acquisition of erythromycin resistance). The PVL positive MRSA were isolated from cutaneous abscesses (two) and sputum. SCCmec IV was the predominant type among CA-MRSA (84.6%) and HA-MRSA (80.7%), followed by type I (7.7% CA-MRSA and 15.4% HA-MRSA), type III (3.8% both) and one type V among the CA-MRSA isolates. Interestingly, type I SCCmec isolates presented a multidrug-resistance phenotype characterised by gentamycin resistance.

Conclusion: As expected, PVL positive strains were found only among CA-MRSA and two out of three were associated to cutaneous abscesses. SCCmec type IV emerged as the most frequent genotype in this series of MRSA without any significant difference among the community or hospital acquired MRSA. To the better of our knowledge this is the first report on the molecular characterisation of Italian CA-MRSA isolates.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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