– Aminoglycoside 3′-phosphotransferase (APH(3′)), also known as aminoglycoside kinase, is an aminoglycoside-modifying enzyme and widely presented in resistant bacteria. These ATP-dependent enzymes phosphorylate the 3′-hydroxyl of a variety of aminoglycosides including kanamycins, neomycins, paromomycins, neamine, ribostamycin, geneticin, and paromamine. These phosphorylated aminoglycosides fail to bind to their respective ribosomal binding sites with high affinity; hence resistance is conferred to the drugs that are phosphorylated. APH(3′) is primarily found in certain species of gram-positive bacteria.