Characterization of High-level Aminoglycoside Resistance in a Strain of Streptococcus pneumoniae

Abstract
The aminoglycoside phosphotransferase (APH)(3′)(5″)-III has been characterized from Streptococcus pneumoniae BM4200, which is resistant to high levels of aminoglycosides. The phosphotransferase was apparently chromosomally-encoded and was responsible for the high-level resistance. The enzyme was not notably pH-dependent, was heterogeneous after isoelectric focusing, with pI values of approximately 4·8 and 5·1, and had an apparent molecular weight of 32500 after SDS-PAGE.