Aminoglycoside Antibiotic-Inactivating Enzymes in Actinomycetes Similar to Those Present in Clinical Isolates of Antibiotic-Resistant Bacteria

TLDR

Streptomyces species encode aminoglycoside‑acetylating enzymes that modify kanamycin, gentamicin, and neomycin, mirroring the resistance enzymes found in gram‑negative bacteria. These findings imply an evolutionary link between actinomycete aminoglycoside‑inactivating enzymes and the resistance determinants of gram‑negative bacteria.

Abstract

Various species of Streptomyces possess aminoglycoside-modifying enzymes. Streptomyces kanamyceticus contains an enzyme that acetylates the 6'-amino group of kanamycin A and B, gentamicin C(1a), and neomycin. Streptomyces spectabilis produces an enzyme that acetylates the 2'-amino group of the hexose ring of gentamicin C(1a). These enzymes catalyze reactions identical to those catalyzed by enzymes found in gram-negative bacteria containing R(antibiotic resistance)-factors. The discovery of these enzymes suggests the possibility of an evolutionary relationship between the aminoglycosideinactivating enzymes (produced by resistance determinants) in bacteria containing R-factors and similar enzymes found in the actinomycetes.