Compositions and methods for treating ophthalmic and otic infections

A topical pharmaceutical composition for treating acute otitis externa infections or ophthalmic infections attributable to a Microbacterium species selected from the group consisting of Microbacterium otitidis and Microbacterium alconae, comprising of one or more compounds of the following formula in an amount effective to eradicate said Microbacterium species:

• wherein:
• A is CH, CF, CCl, C—OCH3, or N;
• X1 is H, halogen, NH2, or CH3;
• R1 is C1 to C3 alkyl, FCH2CH2, cyclopropyl or phenyl, optionally mono-, di- or tri-substituted by halogen, or A and R1 together can form a bridge of formula C—O—CH2—CH(CH3);
• R2 is H, C1 to C3 alkyl (optionally substituted by OH, halogen or NH2), or 5-methyl-2-oxo-1,3-dioxol-4-yl-methyl;
• and
• B is a selected from the group consisting of:
• wherein:
• Y is O or CH2;
• R3 is C2—C5 alkoxyl, CH2—CO—C6H5, CH2CH2CO2R′, R′O2C—CH═C—CO2R′, CH═CH—CO2R′ or CH2CH2—CN,
• wherein:
• R′ is H or C1 to C3 alkyl;
• R4 is H, C2 to C3 alkyl, C2—C5 alkoxyl, CH2—CO—C6H5, CH2CH2CO2R′, R′O2C—CH═C—CO2R′, CH═CH—CO2R′, CH2CH2—CN or 5-methyl-2-oxo-1,3-dioxol-4-yl-methyl,
• wherein:
• R′ is H or C1 to C3 alkyl;
• and their pharmaceutically useful hydrates and salts;
• and a pharmaceutically acceptable vehicle therefor.