Production of Antibacterial Compounds from Aspergillus terreus Against MDR Acinetobacter baumannii Using Co-culture

Abstract

Acinetobacter baumannii is a bacterial pathogen, associated with hospital and community acquired infections. It is one of the most common, opportunistic, and serious multidrug resistant bacteria (MDR). It is considered a global problem. The use of natural compounds such as fungal metabolites as an alternative to antibiotics is being explored to overcome the issue of antimicrobial resistance. Among fifty fungal spp. isolated from different sources, only Aspergillus terreus showed an antibacterial effect against A. baumannii. Co-culture is applied to produce bioactive compounds in higher amounts and/or to induce the production of new secondary metabolites. Several solvents and chromatographic techniques were used to isolate, fractionate, and purify Aspergillus terreus/ Acinetobacter baumannii co-culture secondary metabolites. Ethyl acetate extract was the most potent extract against MDR A. baumannii, in comparison to chloroform and methanol extracts. Characterization and structure elucidation of the purified compound isolated from ethyl acetate extract were performed using LC-MS, 1H NMR, and IR. The compound was identified as terreusinone A with a minimum inhibitory concentration of 160 µg.µl-1against MDR A. baumannii. This is the first record to determine the antibacterial effect of terreusinone A particularly against MDR A. baumannii.