Promoters P3, Pa/Pb, P4, and P5 Upstream from bla(TEM) Genes and Their Relationship to β-Lactam Resistance

Using an isogenic system, we have determined the impact that the four promoters known to control bla(TEM) gene expression have on β-lactamase activity. For both TEM-1 and TEM-30, this activity gradually increased in relation to the presence of promoters P3, Pa/Pb, and P4 upstream of the corresponding gene. Promoter P5, only found upstream of the bla(TEM-1B) gene, was related to the highest expression of this gene.