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Updated: Mar 12, 2026
Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Staphylococcal Cassette Chromosome mec Types Among Methicillin-Resistant Staphylococcus aureus in Northern Iran
Akram Taherirad1, Roghayeh Jahanbakhsh1, Fatemeh Shakeri1
1Microbiology Department, Golestan University of Medical Sciences, Gorgan, IR Iran.
Background:
Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial and community-acquired infections around the world. Staphylococcal cassette chromosome mec (SCCmec) typing methods are often used to study MRSA molecular epidemiology.
Objectives:
The current study was designed to explore the distribution profiles of different SCCmec types among methicillin-resistant S. aureus strains isolated from hospitals in Gorgan, in northern Iran, and to correlate the types into observed bacterial virulence factors.
Materials And Methods:
Staphylococcal cassette chromosome mec typing of 62 MRSA strains isolated from patients and health-care workers in Gorgan was performed using multiplex polymerase chain reaction (PCR) assay. The prevalence of the strains was then compared according to isolation source, antibiotic susceptibility profiles, biofilm production, and the presence of the Panton-Valentine gene in isolates.
Results:
The most common SCCmec type was type III, with a frequency rate of 76%, followed by types IV, I, and V, with frequency rates of 11.2%, 4.8%, and 3.2%, respectively; three isolates (4.8%) were not typeable by this method. SCCmec type I was only isolated from blood culture, and types IV and V were mainly isolated from wounds and urine samples; SCCmec type III was isolated from all of the clinically samples. All of the MRSA strains that were isolated from healthy carriers were type III. Multidrug resistance in the type III strains was higher compared to the other types. The frequencies of Panton-Valentine and biofilm production were significantly lower in the type III strains compared to the other SCCmec types (P < 0.05).
Conclusions:
Similarly to other geographical regions of Iran, the SCCmec type III MRSA strain was the most frequently isolated strain from patients in Gorgan. Staphylococcal cassette chromosome mec type III showed fewer virulence factors compared to other SCCmec types.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) type III strains are most common in Gorgan, Iran. These strains exhibit lower virulence factors compared to other MRSA types, despite higher multidrug resistance.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a significant global cause of healthcare-associated and community-acquired infections.
- Staphylococcal cassette chromosome mec (SCCmec) typing is crucial for understanding MRSA's molecular epidemiology.
Purpose of the Study:
- To investigate the distribution of SCCmec types in MRSA strains from Gorgan, Iran.
- To correlate SCCmec types with bacterial virulence factors and clinical characteristics.
Main Methods:
- Sixty-two MRSA strains were analyzed using multiplex polymerase chain reaction (PCR) for SCCmec typing.
- Prevalence was compared based on isolation source, antibiotic resistance, biofilm production, and Panton-Valentine gene presence.
Main Results:
- SCCmec type III was the predominant type (76%), followed by types IV, I, and V.
- Type III MRSA was isolated from all sample types, including healthy carriers, and showed higher multidrug resistance.
- Type III strains had significantly lower frequencies of Panton-Valentine and biofilm production compared to other types.
Conclusions:
- SCCmec type III is the most prevalent MRSA strain in Gorgan, Iran, consistent with other regions.
- MRSA strains of SCCmec type III possess fewer virulence factors than other identified SCCmec types.
