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Antimicrobial resistance and virulence markers in methicillin sensitive Staphylococcus aureus isolates associated

Abdullah Sarkar1, Adeola Raji1, Ghada Garaween1

  • 1College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.

Microbial Pathogenesis
|January 23, 2016
PubMed

Insights

Most Staphylococcus aureus nasal carriage in medical students involved methicillin-susceptible strains (MSSA). These MSSA isolates carried concerning antimicrobial resistance and virulence genes, similar to those found in MRSA.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Genetics

Background:

  • Staphylococcus aureus colonization is a primary risk factor for infections and dissemination.
  • Understanding the genetic makeup of colonizing strains is crucial for infection control.

Purpose of the Study:

  • To investigate antimicrobial resistance and virulence markers in Staphylococcus aureus nasal isolates from medical students.
  • To characterize the genetic diversity and potential for dissemination of S. aureus nasal carriage.

Main Methods:

  • Nasal swabs collected from 97 medical students in Riyadh, Saudi Arabia.
  • Bacterial culture, identification, antimicrobial susceptibility testing, and MRSA screening using chromogenic agar.
  • Molecular characterization via StaphyType DNA microarray.

Main Results:

  • 43% of students (32/97) carried S. aureus; one MRSA and 31 MSSA.
  • Seventeen clonal complexes (CC) identified, with CC15-MSSA being most frequent.
  • MSSA isolates harbored diverse virulence genes (hemolysin, enterotoxin, exfoliative) and resistance markers, including those typically found in MRSA.

Conclusions:

  • Low MRSA carriage but significant presence of resistance and virulence genes in MSSA isolates.
  • Incomplete SCCmec elements and the co-carriage of resistance/virulence genes in MSSA are a public health concern.
Keywords:
DNA microarrayMethicillin resistant Staphylococcus aureusNasal colonizationVirulence genes

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