The present invention refers to a composition, comprising metallic silver nanoparticles supported on a carrier, the carrier being in the form of particles, wherein the carrier is selected from an inert carrier or an antibiotic, the composition further comprising at least one antibiotic in the case the carrier is an inert carrier. The invention also discloses a nanosystem comprising said composition or a mixture of silver nanoparticles and at least one antibiotic, for use in the treatment of an infection caused by at least one strain of bacteria resistant to at least one antibiotic. The invention further discloses pharmaceutical compositions and methods for the preparation of the compositions and nanosystems.
