Antibacterial Effect of Nanoparticles Against Antibiotic Resistant Gram Positive and Gram-Negative Bacteria

The increasing emergence of bacterial resistance occurred mainly due to continuous persistent exposure to antibiotics causing high morbidity and mortality so studies in controlling the infections caused by these strains are required. Nanoparticles have been reported as non-antibiotic therapeutic agents, that have antibacterial effect against many pathogens including bacteria and fungi. Fifty bacterial isolates were divided into two groups 25 methicillin-resistant Staphylococcus aureus (MRSA) and 25 carbapenem-resistant gram-negative isolates collected from different infection sites from patients admitted to AL-Zahraa university hospital, The isolates were identified by routine culture and sensitivity using disc diffusion susceptibility test and by the Vitek 2 automated system. The synthetic nanoparticles AgNPs, ZnONPs and chitosan NPs were characterized by TEM, EDX and FTIR. The antibacterial effect of NPs was screened using agar well diffusion method. The cytotoxicity of NPs towards human lung fibroblasts was determined using cell culture assays. The minimum inhibitory concentration (MIC) of NPS and antibacterial effects alone and in combination with antibiotic ciprofloxacin were determined against twenty isolates, ten MRSA and ten carbapenem-resistant E. coli and klebsiella isolates using the microdilution method. The biocompatible concentration of AgNPs (6 µg/mL), ZnONPs (500 µg/mL) and chitosan (100 µg/mL) were non-cytotoxic but also showed no antibacterial effects However, when combined with antibiotic ciprofloxacin, the biocompatible concentration of NPs resulted in significant inhibition of bacterial growth for multiple bacterial species. This study presents a promising strategy with further testing in vivo, to develop novel antimicrobial agents and strategies to confront emerging antimicrobial resistance.