mecC

MecC is a gene that confers resistance to beta-lactam antibiotics in staphylococci. It is a homolog of the mecA gene, encoding a penicillin-binding protein with low affinity for beta-lactams, and is responsible for a methicillin-resistant phenotype. The mecC gene was first described in Staphylococcus aureus isolates in 2011. It is typically carried on a variable mobile genetic element known as the staphylococcal cassette chromosome mec (SCCmec), distinct from the mecA-containing cassettes.

MecC encodes PBP2c, a penicillin-binding protein that reduces the effectiveness of beta-lactams such as methicillin and oxacillin. Clinically, mecC-mediated resistance can complicate detection because many routine diagnostic tests target mecA or PBP2a production; laboratories may require mecC-specific PCR assays or whole-genome sequencing to identify mecC-MRSA or mecC-positive methicillin-resistant staphylococci.

Distribution and hosts: mecC has been detected in Staphylococcus aureus and in some other Staphylococcus species, in human clinical isolates as well as animal-associated strains, with reports from several regions around the world. It is generally less prevalent than mecA but remains a documented mechanism of resistance.

Public health relevance: The presence of mecC in clinical and veterinary settings highlights the need for broad molecular surveillance and diagnostic assays capable of detecting mec gene variants. Treatment decisions remain guided by the overall antibiotic susceptibility profile of the isolate.