Comprehensive Review: MRSA Molecular Characterization, SCCmec Evolution, and Typing Methods
This extensive review traces the molecular evolution of methicillin-resistant Staphylococcus aureus from hospital-associated to community-acquired and livestock-associated lineages. It details the 13 known SCCmec types, the mecA gene and its homologues (mecB, mecC, mecD), and the full spectrum of molecular typing methods from historical approaches through whole-genome sequencing. The review provides essential context for clinical laboratories performing MRSA surveillance and outbreak investigation.
The original study
Methicillin-Resistant Staphylococcus aureus: Molecular Characterization, Evolution, and Epidemiology.
- Authors
- Lakhundi S, Zhang K
- Journal
- Clinical microbiology reviews
- Type
- Journal Article, Research Support, Non-U.S. Gov't, Review
- PMID
- 30209034
Original abstract
Staphylococcus aureus, a major human pathogen, has a collection of virulence factors and the ability to acquire resistance to most antibiotics. This ability is further augmented by constant emergence of new clones, making S. aureus a "superbug." Clinical use of methicillin has led to the appearance of methicillin-resistant S. aureus (MRSA). The past few decades have witnessed the existence of new MRSA clones. Unlike traditional MRSA residing in hospitals, the new clones can invade community settings and infect people without predisposing risk factors. This evolution continues with the buildup of the MRSA reservoir in companion and food animals. This review focuses on imparting a better understanding of MRSA evolution and its molecular characterization and epidemiology. We first describe the origin of MRSA, with emphasis on the diverse nature of staphylococcal cassette chromosome mec (SCCmec). mecA and its new homologues (mecB, mecC, and mecD), SCCmec types (13 SCCmec types have been discovered to date), and their classification criteria are discussed. The review then describes various typing methods applied to study the molecular epidemiology and evolutionary nature of MRSA. Starting with the historical methods and continuing to the advanced whole-genome approaches, typing of collections of MRSA has shed light on the origin, spread, and evolutionary pathways of MRSA clones.