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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Surveillance of methicillin-resistant Staphylococcus aureus isolated in Torino (northwest Italy)
Sabrina Crivellaro1, Ilaria Leone, Ornella Bianco
1Department of Clinical and Biological Sciences, University of Torino, S. Luigi Gonzaga Hospital, Regione Gonzole 10, 10043 Orbassano (Turin), Italy.
Abstract:
Nosocomial infections by methicillin-resistant Staphylococcus aureus (MRSA) are an increasing cause of morbidity and mortality. Recently, a worldwide increase of community-acquired MRSA infections has also been recorded. The purpose of this study was to assess the frequency of MRSA isolation from in- and outpatients admitted to an academic teaching hospital near Torino (northwest Italy) in 1 year and to characterize 90 clinical isolates of MRSA collected in the same period. Antimicrobial susceptibility and the presence in the isolates of the Panton-Valentine leukocidin (PVL) gene were assessed. Molecular epidemiology was performed by SCCmec and capsule typing, and by pulsed-field gel electrophoresis. The global proportion of MRSA isolated was 33.1%. Characterization performed on 90 MRSA revealed a high percentage of resistance to ciprofloxacin and erythromycin, and the presence of the PVL gene in one strain only. Most of the MRSA strains circulating in the Torino district belonged to SCCmec types II and I, and the 67.6% resulted positive for the cap 5 gene. The pulsotype analysis permitted to observe a clonal heterogeneity of the isolates and a higher similarity in relation to singular mec types; only few nosocomial clones could account for a local outbreak of a sporadic isolate.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) infections are rising. This study analyzed MRSA strains from a hospital in Italy, finding high resistance to certain antibiotics but limited spread of specific virulent genes.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Nosocomial and community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a growing global health concern.
- Understanding the prevalence and characteristics of MRSA is crucial for effective infection control and treatment strategies.
Purpose of the Study:
- To determine the frequency of MRSA isolation among patients at an academic teaching hospital near Torino, Italy.
- To characterize the antimicrobial susceptibility, virulence factors (Panton-Valentine leukocidin gene), and molecular epidemiology of clinical MRSA isolates.
Main Methods:
- Prospective study over 1 year assessing MRSA isolation rates from inpatients and outpatients.
- Antimicrobial susceptibility testing, PCR for Panton-Valentine leukocidin (PVL) gene detection.
- Molecular typing including SCCmec and capsule typing, and pulsed-field gel electrophoresis (PFGE).
Main Results:
- MRSA accounted for 33.1% of all Staphylococcus aureus isolates.
- High resistance rates observed for ciprofloxacin and erythromycin among 90 characterized MRSA isolates.
- The PVL gene was present in only one MRSA strain; most strains carried SCCmec types II and I and the cap 5 gene.
Conclusions:
- MRSA strains in the Torino area exhibit significant antimicrobial resistance, particularly to ciprofloxacin and erythromycin.
- The circulating MRSA strains show clonal heterogeneity, with SCCmec types II and I being predominant.
- Limited presence of the PVL gene suggests a lower risk of severe community-acquired infections from these specific strains, though nosocomial clones warrant continued surveillance.
