In vitro and in vivo attenuation of Salmonella resistance using a novel synthesized chloramphenicol magnesium Nano-complex

Abstract

In this study, Chloramphenicol-Mg-Nano-complex (CHL-Mg-NC) was synthesized as a novel antimicrobial agent to attenuate chloramphenicol resistant Salmonella clinical isolates in vitro and in vivo. The CHL-Mg-NC was prepared in presence of gamma radiation and validated by SEM, DLS, Zeta potential, and FTIR, that revealed typical CHL-Mg-NC characteristics. The Phenotypes, biochemical investigations and molecular identification assays defined Salmonella isolates and further detection of invA gene in S. Paratyphi A NCRR-CHR1, S. Enteritidis NCRR-CHR2 and S. Typhimurium NCRR-CHR3 were appraised. In vitro anti-Salmonella efficacy of CHL-Mg-NC was assessed against Salmonella isolates in addition to Typhimurium ATCC 700720. Gamma radiation improved CHL-Mg-NC synthesis in dose-depend manner up to 5 kGy. CHL-Mg-NC showed MIC at a range from 0.156 to 0.625 μg/mL and MBC from 0.3125 to 2.5 μg/mL with MBC/MIC ratio less than or equal to 4. CHL-Mg-NC inhibited biofilm formation in the range of 45.31 %–100 %. It also had bactericidal activity at 2MIC within the low time ranged from 2h to 4h. The in vivo efficacy of CHL-Mg-NC was observed by the reduction in the number of viable Salmonella recovered from feces in infected mice and showed evident improvement in CHL-Mg-NC treated groups.CHL-Mg-NC has no significant cytotoxic effects on normal cells and CC₅₀ is 13.5 μg/mL against CACO2 cells. Acute toxicity of CHL-Mg-NC indicates that the CHL-Mg-NC is safe at high concentrations.