Methods and compositions are provided for treating selected bacterial infections wherein the anti-bacterially active ingredient is a compound of the following formula: ##STR1## wherein R' and R" are each independently a straight chain or branched chain alkyl group having from 5 to 8 carbon atoms, M is NH.sub.4, Na, K or Ca, and x is 1 when M is Na, K or NH.sub.4, and x is 2 when M is Ca.
