Are sea sponges a key part of the complex solution to antimicrobial resistance?

Abstract

With the impending threat of antimicrobial resistance, now a widely-recognised phenomenon, researchers have begun to look to the deep in search of solutions to one of the greatest threats posed to human health. Boosted by public health initiatives, government endorsement and a concerted effort on the part of researchers worldwide, we are now beginning to work towards potential alternatives to the scenario outlined by Lord O’Neill in 2016 in the Review on Antimicrobial Resistance. But have we begun to turn the tide? Antimicrobial discovery, as part of the much-needed and multi-faceted approach to tackling antimicrobial resistance (AMR), has necessitated that the search for novel compounds be widened to new and unexplored environments. Sponges have emerged in recent decades as the most prolific source of novel biological compounds from the marine environment. Over the last 45 years, sponges have become the most widely sampled marine phyla in the hunt for novel bioactive compounds. Initially, antimicrobial activity in sponge extracts was believed to be derived from the sponge itself, but the rediscovery of compounds across distinct sponge species, as well as the similarity of the compounds to those observed in terrestrial micro-organisms has confirmed that many sponge antimicrobials are in fact of microbial origin. For this reason, focus has shifted towards investigation of the microbial constituents of the sponge microbiota. The use of metagenomics to characterise the microbial inhabitants of specific species, alongside efforts to culture these sponge-associated microbes, is providing sponge researchers with an ever-growing bank of promising drug leads.