bacterial antibiotics that irreversibly bind to the 30S ribosomal subunit causing it to distort and malfunction. Can cause severe side effects including damage to the inner ear and the kidney. Generally not effective against anaerobes, enerococci, and streptococci because they enter the cell during respiratory metabolism. sometimes used synergistically with penicillin. Include streptomycin, gentamycin, tobramycin, and neomycin