The present invention relates to the field of therapeutics and, more in particular, to pharmaceutical compositions for the prevention and / or treatment of bacterial infections and antibacterial-induced dysfunctions. The compositions of the present invention demonstrate high species-specificity in inhibiting the growth of a small number of bacterial species, and most importantly are effective also against
multi drug resistant (MDR) clinical isolate species. Interestingly, one of those combinations pairs a non-
antibiotic drug,
vanillin, with an
antibiotic drug,
spectinomycin, to demonstrate a surprisingly strong
inhibitory effect on the growth of clinically relevant
Gram-negative pathogenic and multi-
drug resistant E. coli isolates. A second set of compounds combines the
polymyxin colistin with loperamide, a
rifamycin, or a macrolide. Importantly, this invention relates to combinations that enable narrow-spectrum antibacterial therapies, constituting a major effort of current and future
drug development efforts in order to prevent major side effects of antibacterial strategies. This invention also relates to pharmaceutical combinations useful to prevent an
adverse effect on the
gut microbiome, induced by the use of antibacterial compounds.