Staphylococcal cassette chromosome mec (Sccmec) classification and typing methods: an overview

Area of Science:

• Microbiology
• Infectious Diseases
• Epidemiology

Background:

• Meticillin-resistant Staphylococcus aureus (MRSA) is a significant cause of both hospital-acquired and community-acquired infections.
• Understanding the epidemiology of S. aureus, particularly MRSA, necessitates effective molecular typing methods for the Staphylococcal Cassette Chromosome *mec* (SCC*mec*) element.
• Recent years have seen the identification of novel SCC*mec* types (VI-XI), subtypes (e.g., IVg-j), and variants, complicating classification.

Purpose of the Study:

• To provide a concise overview of the current classification of SCC*mec* elements.
• To discuss the advantages and disadvantages of various SCC*mec* typing methods used for MRSA surveillance.

Main Methods:

• Review of existing literature on MRSA molecular typing and SCC*mec* classification.
• Analysis of established and emerging SCC*mec* typing techniques, including pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), spa typing, and direct SCC*mec* type assignment.

Main Results:

• The SCC*mec* element exhibits significant diversity, with numerous new types, subtypes, and variants identified.
• Current typing methods, while valuable, have limitations in comprehensively characterizing the evolving SCC*mec* landscape.

Conclusions:

• Accurate and updated SCC*mec* typing is crucial for effective MRSA epidemiological surveillance.
• Continued development and refinement of molecular typing methods are needed to keep pace with the genetic diversity of MRSA strains.