TABLE 1.

Genetic factors required for MRSA β-lactam resistance

Gene/operon	SAOUHSCa	Functional class	Function	Reference(s)
mecA		Extracellular PG synthesis	Encodes the heterologous penicillin-binding protein PBP2A with low affinity for β-lactam antibiotics	158
mecB		Extracellular PG synthesis	Encodes a heterologous penicillin-binding protein PBP2B with low affinity for β-lactam antibiotics	46
mecC		Extracellular PG synthesis	Encodes a heterologous penicillin-binding protein PBP2C with low affinity for β-lactam antibiotics	41, 42
pbp4	00646	Extracellular PG synthesis	PBP with transpeptidase activity	47

^aS. aureus 8325 genome locus tag.