Molecular epidemiology of methicillin-resistant Staphylococcus aureus in a northern Italy hospital

Abstract number: P1574

Parlato C., Cavallerio P., Fossati L., Allice T., Serra R.

Objectives: We conducted a one year-study on the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in our hospital, San Giovanni Battista of Turin (Italy), from August 2007 to August 2008. The aim was to identify one or more MRSA clones within circulating in 58 wards, including Intensive Care Units (ICUs), surgical and specialistic surgical units, general and specialistic medicines, transplant organ units, using molecular epidemiological methods.

Methods: 225 MRSA isolates were derived from clinical samples of patients with active infections like surgical wound infections (22%), urine (16%), blood (15%), bronchoaspirate (13%), endovasal catheter (8%), wound infections (8%), bronchoalveolar lavage (5%), tracheal aspirate (4%), cerebrospinal fluid (3%), perithoneal fluid (2%), drainage (1%), biopsy (1%), bile (1%), pericardial fluid (1%), transplant organ preservation fluid (0.5%) and perithoneal exhaust (0.5%). All isolates were analysed by PFGE, rep-PCR, SCCmec typing, PVL-typing and spa-typing.

Results: the isolates were classified into following SCCmec types: 48 SCCmec type I (21.3%), 106 SCCmec type II (47.1%), 2 SCCmec type III (0.8%), 66 SCCmec type IV (29.3%) and 3 SCCmec type V (1.3%). Of the SCCmec type IV, only 2 were positive for PVL (0.9%). Overall, 20 spa types were detected, with t242, t008 and t001 being most prevalent (44.9%, 23.5% and 21.3%, respectively). PFGE and rep-PCR showed specific profiles that reflect the molecular features of strains.

Conclusion: using molecular typing and sequence-based methods we were able to identify the presence of three MRSA clones within the hospital. The most common strain is t242 with SCCmec type II. In addition to the b-lactams resistance, the strain is resistant to ciprofloxacin, levofloxacina and erythromycin but is sensitive to gentamicin, rifampicin and tetracyclines. The other two, less prevalent MRSA clones (6.6% and 1.9% of all isolates, respectively), were t008 (SCCmec type IV) and t001 (SCCmec type I). Our hospital is the first in Italy, where t242 reached an endemic level.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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