Effective release of Ciprofloxacin and Rifampicin antibiotics from alginate-chitosan complex and its application against clinical strains of Staphylococcus aureus

This study aimed to characterize the antimicrobial and anti-biofilm activity of ciprofloxacin (CIP) and rifampicin (RMP) loaded on the calcium alginate (CaAlg) backbone through the electrostatic interaction of CaAlg/antibiotic (s) and chitosan-TPP nanoparticles (Cs-TPP NPs). The shape and functional groups were identified by scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy. SEM images show that the nanoparticles are spherical and granular with an average size of about 100–500 nm. FT-IR results showed bonds corresponding to the Cs-TPP NPs and CaAlg-Antibiotics (CaAlg-CIP, CaAlg-RMP) after the loading process. The tube adherence method (TM) was used to screen potent biofilm producers. The anti-biofilm capacity of Cs/CaAlg-CIP and Cs/CaAlg-RMP, along with free antibiotics was used against clinical strains in the tube method and results showed that the use of sub-MICs of nano-drugs ( 1 / 2 MIC) inhibited biofilm formation in the tested strains compared to free CIP and RMP ( P  < 0.05). The potential antimicrobial effect of Cs/CaAlg-CIP and Cs/CaAlg-RMP NPs against clinical strains was also evaluated using minimum inhibitory concentration (MICs) and a time-depending killing method. A robust inhibitory effect on bacterial growth even at low concentrations of Cs/CaAlg-CIP and Cs/CaAlg-RMP NPs (CONC 4 and 2 µg.mL ─1 ) was observed compared with free drugs (CIP at 32 and RMP at 8.0 µg.mL ─1 ), ( P  < 0.05). The time-kill kinetics assay showed that Cs/CaAlg-CIP and Cs/CaAlg-RMP NPs had faster and more lasting antibacterial effects than the free drug (s) on the tested strains. This study shows that loading CIP and RMP into CaAlg scaffolds and complexes with chitosan-TPP nanoparticles using the emulsification/internal gelation method increases the antimicrobial activity of antibiotics against clinical strains of S. aureus and thus might serve as a new type of antimicrobial compounds for the treatment of bacterial infections.