MecA gene

The mecA gene is a gene found in bacterial cells. The most commonly known carrier of the mecA gene is the bacterium known as MRSA. The mecA gene allows a bacterium to be resistant to antibiotics such as Methicillin, Penicillin, Erythromycin, Tetracyclin and other penicillin-like antibiotics. The mecA gene does not allow the ringlike structure of penicillin-like antibiotics to attack the enzymes that help form the cell wall of the bacterium (transpeptidases), and hence the bacteria is allowed to replicate as normal.

The mecA gene encodes the protein PBP2A (Penicillin binding protein 2A). PBP2A has a low affinity for beta-lactams such as Methicillin, Penicillin, and this enables transpeptidase activity in the presence of beta-lactams to allow cell wall synthesis.

It is also found in Staphylococcus aureus and Streptococcus pneumoniae resistant to penicillines.