This in turn , causes mecA to be constitutive transcription of the mecA .
The S. aureus strains isolated from humans either lack these regulatory elements , or contain mutations in these genes that cause a loss of function of the protein products that inhibit mecA .
This causes mecA to be constitutive transcription of the mecA .
The S. aureus strains isolated from humans either lack these regulatory elements , or contain mutations in these genes that cause a loss of function of the protein products that inhibit mecA .