Protein profiles of Klebsiella pneumoniae KW grown in the absence and presence of copper were compared. Overexpression of a 45kDa protein (yellow arrow), low expression of a 33kDa protein (green arrow), disappearance or undetectable expression of proteins at 50, 30-35 and around 23kDa (red arrow) and appearance of 150 and 55kDa proteins (blue arrow) as result of the presence of Cu++ were detected.