The antimicrobial spectrum of honey was investigated by placing two drops into each of the wells made on culture media on which pure cultures of various organisms obtained from surgical specimens were grown. The organisms were grown under both aerobic and anaerobic environments. Fungal cultures of common fungi causing surgical infections or wound contaminations were mixed with 100%, 50% and 20% unprocessed honey. Growth inhibition was complete in the media containing 100%, partial in media containing 50% and no inhibition was produced by 20% honey. Unprocessed honey inhibited most of the fungi and bacteria causing wound infection and surgical infection except Pseudomonas aeruginosa and Clostridium oedematiens. Apart from Streptococcus pyogenes which is only moderately inhibited, golden syrup, a sugar syrup with similar physical properties as honey, did not inhibit any of the bacteria or fungi tested, demonstrating that honey is superior to any hypertonic sugar solution in antimicrobial activity. Honey is thus an ideal topical wound dressing agent in surgical infections, burns and wound infections.

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Bacteria employ secondary metabolism to combat competitors, and xenobiotic metabolism to survive their chemical environment. This project has aimed to introduce a bacterial collection enabling comprehensive comparative investigations of those functions. The collection comprises 120 strains (Proteobacteria, Actinobacteria and Firmicutes), and was compiled on the basis of the broad taxonomic range of isolates and their postulated biosynthetic and/or xenobiotic detoxification capabilities. The utility of the collection was demonstrated in two ways: first, by performing 5144 co-cultures, recording inhibition between isolates and employing bioinformatics to predict biosynthetic gene clusters in sequenced genomes of species; second, by screening for xenobiotic sensitivity of isolates against 2-benzoxazolinone and 2-aminophenol. The co-culture medium of Bacillus siamensis D9 and Lysinibacillus sphaericus DSM 28T was further analysed for possible antimicrobial compounds, using liquid chromatography-mass spectrometry (LC-MS), and guided by computational predictions and the literature. Finally, LC-MS analysis demonstrated N-acetylation of 3,4-dichloroaniline (a toxic pesticide residue of concern) by the actinobacterium Tsukamurella paurometabola DSM 20162T which is highly tolerant of the xenobiotic. Microbial collections enable "pipeline" comparative screening of strains: on the one hand, bacterial co-culture is a promising approach for antibiotic discovery; on the other hand, bioremediation is effective in combating pollution, but requires knowledge of microbial xenobiotic metabolism. The presented outcomes are anticipated to pave the way for studies that may identify bacterial strains and/or metabolites of merit in biotechnological applications.

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