Antimicrobial metabolites from pig nasal microbiota

Abstract

The mammal microbiome is considered an attractive source of bioactive compounds, including antibiotics. In this work, we studied cultivable microorganisms from the nasal microbiota of the Hungarian domestic pig (Sus domesticus). Taxonomy positions of the 20 isolated strains (18 bacteria, 1 yeast, 1 fungus) were determined by phylogenetic analysis, morphological study and a substrate utilization assay. The strains were subjected to antibiotic susceptibility testing and antimicrobial activity screening. Pseudomonas aeruginosa strain SM-11 was found to produce 4 known antibacterial molecules (pyocyanine, pyochelin, pyoluteorin, monorhamnolipid). Production of pyocyanine was induced by cocultivation with test microorganisms Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922. The results suggest that the mammal microbiota might serve as a valuable source of antimicrobial-producing strains, including those of rare taxa. Cocultivation techniques are promising approach to explore antimicrobials from silent biosynthetic gene clusters.