A compound of formula: wherein: R1 is H; and R2 is -NR5R6; or R1 is -NR5R6; and R2 is H; Wherein R5 is H and R6 is -(CH 2)nNR7R8 or R6 is H and R5 -(CH 2)nNR7R8, wherein n is 2-10; and R7 and R8 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl; substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein the substituted alkyl(s), substituted allyl(s), substituted aryl(s), substituted aralkyl(s) and substituted cycloalkyl(s) comprise(s) one or more identical or different substitutions selected from alkyl, allyl, aryl, cycloalkyl and aralkyl; and R3 and R4, together with the carbon atoms to which they are attached, form a spirocyclic structure of formula II: wherein R10 is H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, or substituted or unsubstituted -(CH 2)pNR13R14, wherein p is 2-10; and R13 and R14 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein substituted alkyl, allyl, substituted aryl, substituted aralkyl, substituted cycloalkyl, and substituted -(CH 2)pNR13R14 comprises one or more identical or different substitutions selected from alkyl, allyl, aryl, cycloalkyl and aralkyl; or a salt thereof, in combination with an aminoglycoside antibiotic for use in preventing or treating a bacterial infection in a subject; or for use in preventing or treating an infection caused by a small-colony variant that has a defect in the electron transport chain, in a subject. R1 is H; and R2 is -NR5R6; or R1 is -NR5R6; and R2 is H; Wherein R5 is H and R6 is -(CH 2)nNR7R8 or R6 is H and R5 -(CH 2)nNR7R8, wherein n is 2-10; and R7 and R8 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl; substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein the substituted alkyl(s), substituted allyl(s), substituted aryl(s), substituted aralkyl(s) and substituted cycloalkyl(s) comprise(s) one or more identical or different substitutions selected from alkyl, allyl, aryl, cycloalkyl and aralkyl; and Wherein R5 is H and R6 is -(CH 2)nNR7R8 or R6 is H and R5 -(CH 2)nNR7R8, wherein n is 2-10; and R7 and R8 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl; substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein n is 2-10; and R7 and R8 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl; substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein the substituted alkyl(s), substituted allyl(s), substituted aryl(s), substituted aralkyl(s) and substituted cycloalkyl(s) comprise(s) one or more identical or different substitutions selected from alkyl, allyl, aryl, cycloalkyl and aralkyl; and R3 and R4, together with the carbon atoms to which they are attached, form a spirocyclic structure of formula II: wherein R10 is H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, or substituted or unsubstituted -(CH 2)pNR13R14, wherein p is 2-10; and R13 and R14 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein substituted alkyl, allyl, substituted aryl, substituted aralkyl, substituted cycloalkyl, and substituted -(CH 2)pNR13R14 comprises one or more identical or different substitutions selected from alkyl, allyl, aryl, cycloalkyl and aralkyl; wherein R10 is H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, or substituted or unsubstituted -(CH 2)pNR13R14, wherein p is 2-10; and R13 and R14 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein p is 2-10; and R13 and R14 are identical or different and are selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted allyl, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, and substituted or unsubstituted aralkyl; wherein substituted alkyl, allyl, substituted aryl, substituted aralkyl, substituted cycloalkyl, and substituted -(CH 2)pNR13R14 comprises one or more identical or different substitutions selected from alkyl, allyl, aryl, cycloalkyl and aralkyl; or a salt thereof, in combination with an aminoglycoside antibiotic for use in preventing or treating a bacterial infection in a subject; or for use in preventing or treating an infection caused by a small-colony variant that has a defect in the electron transport chain, in a subject.