Plasmids isolated from Klebsiella pneumoniae strains that caused outbreaks in pediatric units in various geographical regions of Argentina harbored genetic determinants for resistance to amikacin. By using restriction endonuclease and Southern blot hybridization analysis it was determined that all of the strains carried plasmids with Tn1331-related elements indicating that transposition of these elements may have played an important role in the dissemination process of resistance to amikacin.