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Spa Diversity among MRSA and MSSA Strains of Staphylococcus aureus in North of Iran

Fatemeh Shakeri1, Abolfath Shojai, Masoud Golalipour

  • 1Islamic Azad University of Lahijan, Lahijan, Iran.

International Journal of Microbiology
|September 24, 2010
PubMed

Insights

The Staphylococcus aureus spa gene length varies between patients and healthy carriers, with shorter spa genes found more frequently in patient strains. Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) strains also show differences in spa gene length.

Area of Science:

  • Microbiology
  • Genetics
  • Infectious Diseases

Background:

  • Protein A, encoded by the spa gene in Staphylococcus aureus, is a significant virulence factor.
  • The length of the spa gene exhibits variability across different S. aureus strains.
  • Understanding spa gene variation is crucial for differentiating strains and understanding pathogenicity.

Purpose of the Study:

  • To investigate the variation in spa gene length in Staphylococcus aureus strains.
  • To compare spa gene length variations between strains isolated from patients and healthy carriers.
  • To analyze spa gene length differences between Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) strains.

Main Methods:

  • DNA extraction and amplification using specific primers for the spa gene.
  • Analysis of spa gene length variations in 208 S. aureus isolates from Gorgan, Iran.
  • Comparison of spa gene lengths between patient (n=121) and healthy carrier (n=87) isolates, and between MRSA (n=59) and MSSA (n=149) strains.

Main Results:

  • No spa gene was detected in 3.8% of strains; 10.6% showed dual bands (1200 and 1400 bp).
  • Single-band spa gene lengths ranged from 1150 to 1500 bp, with 1350-1400 bp being the most prevalent (37%).
  • Shorter spa bands (1150-1200 bp) were significantly more frequent in patient strains. Longer spa genes (1350-1400 bp) were more prevalent in MSSA than MRSA (P < .05).

Conclusions:

  • Spa gene length in Staphylococcus aureus is influenced by Methicillin resistance status.
  • The source of S. aureus isolation (e.g., patient vs. carrier, infection type) correlates with spa gene length variations.
  • Spa gene length analysis provides insights into the epidemiology and pathogenicity of S. aureus strains.

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