Entomogenous fungiisolated from Cryptotympana atrata with antibacterial and antifungal activity.

Abstract

Although many entomogenous fungi have been discovered over the years, few studies on the crude extracts of fungi isolated from Cryptotympana atrata with antibacterial and antifungal activity were reported. In this study, total twenty entomogenous fungi were isolated for the first time. And among of them, two pure cultures were identified as Purpureocillium lilacinum and Aspergillus fumigatus with apparent morphology, microscopic identification and 18S rRNA gene sequence. The active strains were fermented to optimize in six different culture media at three different pH values. The antibacterial and antifungal activities of the metabolites were more potent and efficient in Fungal medium 3# at a pH of 6.2 than in the other tested media or at the other tested pH values. Total seven human pathogens and one insect pathogen were used to evaluate the antibacterial and antifungalactivity of crude extracts, among which 25% of the extracts exhibited antifungal activity against Verticillium lecanii, while 33.3% and 47.2% of the extracts exhibited antibacterial activity against the important human pathogens Staphylococcusaureus and Bacillus cereus, respectively. The range of the MICs was from 15.6 to 250μg mL-1, and 35% of the fungal metabolites exhibited antibacterial activity against Pseudomonas aeruginosa, Bacillus thuringiensis and Enterobacter aerogenes at 1000μgmL-1 except the previously described antibacterial activities. Furthermore, the phylogeneticrelationships of the two identified fungi were also constructed. In brief, it is the first reporting about enthompathogenic fungi from Cryptotympana atrata and provides candidate strains with potential use as biological agents and against multidrug-resistant organisms.