Biocompatible, antibacterial, polymeric hydrogels active against multidrug-resistant Staphylococcus aureus strains for food packaging applications

Microbial infections caused by multidrug-resistant (MDR) bacteria have become a public health threat and cause substantial morbidity and mortality in hospitals as well as in the community and livestock. Pseudomonas aeruginosa YUSA1 isolated from freshwater was found to contain an antagonistic compound against MRSA and other MDR S. aureus strains. The crude ethyl acetate extract (CEE) of cell-free supernatant exhibited in vitro antibacterial and antibiofilm properties against MRSA. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of CEE (as determined by broth-dilution) against MRSA were 25 and 50 μg/ml, respectively. The effect of CEE on MRSA biofilm formation was assessed by crystal violet staining and an MTT viability assay. Pretreatment of human skin fibroblasts (HSFs) with CEE dose-dependently inhibited MRSA adhesion and invasion, and in vitro cytotoxicity analysis showed CEE was compatible with HSFs at its MIC and MBC. In addition, an CEE containing poly(vinyl alcohol) (PVA/CEE) hydrogel fabricated by freeze-drying method exhibited significant anti-MRSA activity at concentrations ≥200 μg/ml. Our results indicate CEE-incorporated PVA polymeric hydrogels have potential use as a food packaging material with antibacterial and antifouling effects on MRSA and other MDR S. aureus strains.