Ciprofloxacin-encapsulated niosome as a novel strategy for enhanced antibacterial and anti-biofilm activity against Staphylococcus aureus isolate from municipal wastewater

Staphylococcus aureus (S. aureus) is one of the important pathogenic bacteria found in urban sewage that shows resistance to different classes of antibiotics. Therefore, the aim of the current study is to assess the antibacterial and anti-biofilm effects of Ciprofloxacin-loaded niosomes (Nio-Cip) formulation on S. aureus isolated from urban wastewater samples. The Nio-Cip was synthesized using the thin-layer hydration method and was formulated based on two variables: lipid content and the ratio of surfactant to cholesterol. The F5 formulation was selected as the optimal formulation among other preparations due to its small size (185 nm) and high drug entrapment efficiency (78.65%). The rate of drug release over 72 h from niosomal formulation was 70% in a biphasic manner. The microbial study showed that out of 50 isolates from urban wastewater, 15 MRSA strains had icaA and icaD genes. Also, the obtained MIC of Nio-Cip was dramatically smaller than that of Cip alone (1–16 μM compared to 8–32 μM). The ability to form biofilm in these strains was greatly reduced after treatment with Cip and Nio-Cip. Based on our abservation, Nio-Cip had higher antibiofilm effects against MRSA than Cip (more than twofold), These results were confirmed with greater down-regulation of icaA and icaD gene expression in Nio-Cip _treated isolates compared to Cip-treated bacteria using the real-time PCR method. Nevertheless, more studies are needed to investigate the anti-biofilm mechanism of Nio-Cip to recognize this method as a novel strategy for the treatment of MDR strains of S. aureus.