Methods and compositions for using a tetracycline compound to treat bacterial infections are described. In one embodiment, for example, the invention provides a method of treating a subject for an infection, comprising administering to said subject an effective amount of 9-[(2,2-dimethyl-propyl amino)-methyl]-minocycline or a salt thereof, such that said subject is treated, wherein said infection is selected from the group consisting of MSSA, MRSA, B-streptococci, Viridans Streptococci, Enterococcus, or combinations thereof.