A potential new source for drugs to fight deadly viruses has been discovered – at the bottom of the Arctic Ocean.
The “promising” antibiotic candidates were found in microbes deep in the sea, say scientists.
Antibiotics are a key component of modern medicine as without them, anyone with open wounds or needing to undergo surgery would be at constant risk of dangerous infections.
But researchers say the world is facing a global antibiotics “crisis” as more and more resistant strains of bacteria are evolving, while the rate of discovery of fundamentally new antibiotics has been much slower.
But they explained that there is reason for hope as 70% of all currently licensed antibiotics have been derived from actinobacteria in the soil, and most environments on Earth have not yet been searched for them.
Scientists say that focusing the search on actinobacteria in other habitats is a “promising” strategy – especially if it were to yield new molecules that neither kill bacteria outright nor stop them from growing, but only reduce their “virulence” or capacity for causing disease.
They explained that is because it is hard for targeted pathogenic strains to evolve resistance under such conditions, while such anti-virulence compounds are also less likely to cause unwanted side effects.
Study corresponding author Professor Päivi Tammela, of the University of Helsinki in Finland, said: “We show how advanced screening assays can identify anti-virulence and antibacterial metabolites from actinobacteria extracts.
“We discovered a compound that inhibits enteropathogenic E. coli (EPEC) virulence without affecting its growth, and a growth-inhibiting compound, both in actinobacteria from the Arctic Ocean.”
Tammela and his team developed a new suite of methods that can test for the anti-virulence and antibacterial effects of hundreds of unknown compounds simultaneously.
They targeted an EPEC strain that causes severe – and sometimes deadly – diarrhea in children under five, especially in developing countries.
EPEC causes disease by adhering to cells in the human gut.
Once it adheres to those cells, EPEC injects so-called ‘virulence factors’ into the host cell to hijack its molecular machinery, ultimately killing it.
The tested compounds were derived from four species of actinobacteria, isolated from invertebrates sampled in the Arctic Sea off Svalbard during an expedition of the Norwegian research vessel ‘Kronprins Haakon’ in August 2020.
The bacteria were then cultured, their cells extracted, and their contents separated into fractions.
Each fraction was then tested in vitro, against EPEC adhering to cultured colorectal cancer cells.
The research team found two unknown compounds with strong anti-virulence or antibacterial activity: one from an unknown strain, called T091-5, and another from an unknown strain, dubbed T160-2, of Kocuria.
The compounds showed two complementary types of biological activity, according to the findings published in the journal Frontiers in Microbiology.
But, unlike the compounds from T160-2, the compound from T091-5 didn’t slow down the growth of EPEC bacteria.
The research team says that means that T091-5 is the most “promising” strain of the two, as EPEC is less likely to ultimately evolve resistance against its anti-virulence effects.
Using advanced analytical techniques, the researchers determined that the active compound from T091-5 was most likely a phospholipid: a class of fatty phosphorus-containing molecules that play important roles in cell metabolism.
Tammela added: “The next steps are the optimization of the culture conditions for compound production and the isolation of sufficient amounts of each compound to elucidate their respective structures and further investigate their respective bioactivities.”
Produced in association with SWNS Talker
