Cloud point (CP)/lower consolute temperature (LCT) of aqueous mixture of TX-100 and a highly recognised anti-diabetic drug metformin hydrochloride (MNH) was analysed in absence/presence of NH₄Cl, NH₄NO₃, (NH₄)₂SO₄ and (NH₄)₂HPO₄. The CP values were found to be decreased with increasing concentrations of ammonium salts. Occurrence of aggregation in respective solution systems might result in declining of corresponding CP. Thermodynamic parameters ( $\mathrm{\Delta }{G}_c^0$, $\mathrm{\Delta }{H}_c^0$ and $\mathrm{\Delta }{S}_c^0$) were calculated at CP. The appearance of positive values of Gibbs free energy ( $\mathrm{\Delta }{G}_c^0$) indicates that clouding in the studied system was thermodynamically non-spontaneous and the degree of non-spontaneity was diminished with increasing in the extents of electrolytes. The computed enthalpy ( $\mathrm{\Delta }{H}_c^0$) and entropy ( $\mathrm{\Delta }{S}_c^0$) values of the system showed negative values in cases of aq. NH₄Cl, (NH₄)₂SO₄ and (NH₄)₂HPO₄ while the negative values tend to reduce with rise of electrolytes content. In case of aq. NH₄NO₃ medium, the reverse results for the $\mathrm{\Delta }{H}_c^0$ and $\mathrm{\Delta }{S}_c^0$ values were detected. The $\mathrm{\Delta }{H}_c^0$ and $\mathrm{\Delta }{S}_c^0$ values in the studied system indicate the presence of electrostatic interaction between TX-100 and MNH in NH₄Cl, (NH₄)₂SO₄, (NH₄)₂HPO₄ media whereas the hydrophobic interactivity might play a great role within the mixture when it was placed in the NH₄NO₃ solution. GRAPHICAL ABSTRACT

The ability of microorganisms to generate resistance outcompetes with the generation of new and efficient antibiotics. Therefore, it is critically required to develop novel antibiotic agents and treatments to control bacterial infections. Green synthesized metallic and metal oxide nanoparticles are considered as the potential means to target bacteria as an alternative to antibiotics. Nanoconjugates have also attracted attention because of their increased biological activity as compared to free antibiotics. In the present investigation, silver nanoparticles (AgNPs), zinc oxide nanoparticles (ZnO NPs), copper oxide nanoparticles (CuO NPs), and iron oxide nanoparticles (FeO NPs) have been synthesized by using leaf extract of Ricinus communis. Characterization of nanoparticles was done by using UV–Vis Spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy Dispersive X-Ray Analyzer, X-ray Diffraction Analysis, and Dynamic Light Scattering Particle Size Analyzer. Interestingly, Streptomycin when combined with AgNPs, ZnO NPs, CuO NPs, and FeO NPs showed enhanced antibacterial activity against clinical isolates of S. aureus which suggested synergism between the nanoparticles and antibiotics. The highest enhanced antibacterial potential of Streptomycin was observed in conjugation with ZnO NPs (11 ± 0.5 mm) against S. aureus. Minimum inhibitory concentration of conjugates of AgNPs, ZnO NPs, CuO NPs, and FeO NPs with streptomycin against S. aureus was found to be 3.12, 2.5,10, and 12.5 μg/mL respectively. The considerable point of the present investigation is that S. aureus, which was resistant to streptomycin becomes highly susceptible to the same antibiotic when combined with nanoparticles. This particular observation opens up windows to mitigate the current crisis due to antibiotic resistance to combat antimicrobial infections efficiently.