In the present study extracellular synthesis of silver nanoparticles (AgNPs) was achieved using cultural supernatant of bacterial isolate Aeromonas dhakensis AS3. Biosynthesis of AgNPs was completed within 120 min by incubating cell free supernatant with silver nitrate solution under illumination. Brown color appearance of solution due to surface plasmon resonance (SPR) and absorption maxima centered at 405 nm was indicated formation of AgNPs. Fourier transform infrared spectroscopy (FTIR) spectrum analysis revealed the presence and association of possible biomolecules with AgNPs during synthesis. Atomic force microscopy (AFM), Field emission scanning electron microscopy (FE-SEM) and High resolution transmission electron microscopy (HR-TEM) showed spherical nanoparticles with an average size of 5 nm. X-ray diffraction (XRD) and Energy Dispersive X-ray (EDX) spectrum confirmed crystallinity and purity of AgNPs. The synthesized AgNPs was found to have significantly independent as well as combined activity against multidrug resistant extended spectrum β-lactamases (ESBLs) producing Acinetobacter junii, E.coli and Klebsiella spp. harboring TEM and/or CTX-M genes. This work demonstrates the possible use of biosynthesized AgNPs to combat ESBLs producing pathogens.