Antibacterial activity and nephrotoxicity of two novel 2″-amino derivatives of arbekacin.

The antibacterial activity of 2″-amino-2″-deoxyarbekacin (AmABK) and 2″-amino-5,2″-dideoxy-5-epiaminoarbekacin (AmABK) was comparable to, or slightly less than, that of arbekacin (ABK) against gram-positive and gram-negative bacteria, including 60 stock cultures and 50 clinical isolates of Pseudomonas aeruginosa, but more potent against 31 isolates of MRSA possessing an aminoglycoside-modifying enzyme APH(2″)/AAC(6'). AmABK and AmABK showed in vivo activity which paralleled in vitro MICs, and were less toxic than ABK in acute toxicity in mice and nephrotoxicity in rats. These results indicate that the 2″-amino group introduced to ABK confers high stabilization to the aminoglycoside-modifying enzymes, while reducing acute and renal toxicities.