Bringing the biorefinery concept to the health-care facilities: use of industrial by-products against multi-drug resistant bacteria

Multi-drug resistant bacteria (MDRB) are a public health issue worldwide, being alternatives to the conventional failing antibiotherapy required. This fact has turned attention to bioactive compounds with antimicrobial activity features. These bioactives can be extracted from several biomasses sources, namely industrial by-products, within a biorefinery concept. The main objective of this Thesis was the design of a novel antiseptic formulation (AF), based on natural plant extracts, obtained from forest/agriculture industries by-products. The antimicrobial activities of three extracts from different sources were studied: Eucalyptus nitens total bark (ENTB) extract, Cynara cardunculus leaves (CcL) extract and dry olive pomace (DOP) extract. Those that presented better antibacterial activity were chosen to be included in the AF. Studies regarding formulation design and its antibacterial performance were made. ENTB extract was the one with better anti-MDRB performance, particularly against Staphylococcus spp., with minimal inhibitory concentrations between 64 and 2048 μg/mL, being included in the AF. The antibacterial activity of ENTB extract-based-AF presented promising results, achieving a 97±2% bacterial growth inhibition after exposure to 45% of AF. In conclusion, the developed AF presents potential to be further investigated, namely for hand sanitation within healthcare environment, but additional adjustments should be executed, namely in order to turn it more appellative to users