Staphylococcus aureus in a northern Italian region: phenotypic and molecular characterization

Scand J Infect Dis. 2012 Jan;44(1):24-8. doi: 10.3109/00365548.2011.603744. Epub 2011 Sep 5.


Background: Staphylococcus aureus is a leading cause of community-acquired infections and healthcare-associated infections. Epidemiological data are useful for understanding the dynamics of the diffusion of this pathogen, and to plan control activities and monitor their efficacy.

Methods: S. aureus isolates were collected in 13 public hospital laboratories of Emilia-Romagna (northern Italy region) during February-March 2009; phenotypic and molecular characterizations of these isolates were performed.

Results: The study sample included 267 isolates, 57 from blood, 81 from respiratory tract, and 129 from wounds; 106 (40%) were methicillin-resistant S. aureus (MRSA). MRSA showed a limited number of circulating clones with 2 predominant spa types--t008 and t041--accounting for 36% and 27% of MRSA isolates, respectively. The t041 type had a higher prevalence of antimicrobial resistance compared to other spa types and accounted for most of the retrieved hetero-vancomycin-intermediate S. aureus (h-VISA), while t008 was more frequently detected in non-hospital isolates. A higher degree of genetic diversity was observed in methicillin-susceptible S. aureus (MSSA), with no predominant clones and low prevalence of antimicrobial resistance. The occurrence of community-acquired MRSA infection appears to be rare in Emilia-Romagna.

Conclusions: In contrast to previous studies reporting Italian data, t008 was the most frequent spa type among MRSA isolates in Emilia-Romagna. The prevalence of antimicrobial resistance of different MRSA spa types could influence their ability to cause infections with hospital onset. The presence of only 2 major MRSA clones circulating in Emilia-Romagna increases the chances that a regional strategy aimed at MRSA prevention will be effective.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / genetics*
  • Bacterial Typing Techniques
  • Drug Resistance, Multiple, Bacterial* / genetics
  • Genotype
  • Humans
  • Italy
  • Methicillin*
  • Methicillin-Resistant Staphylococcus aureus / classification
  • Methicillin-Resistant Staphylococcus aureus / genetics*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Microbial Sensitivity Tests
  • Penicillin-Binding Proteins
  • Phenotype
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / genetics*
  • Staphylococcus aureus / isolation & purification


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Penicillin-Binding Proteins
  • mecA protein, Staphylococcus aureus
  • Methicillin