Powerful antibiotics found in deep Arctic waters to tackle resistant bacteria

Researchers have uncovered potential antibiotic candidates in Arctic marine microorganisms.

Dr. Päivi Tammela and her team at the University of Helsinki focussed on actinobacteria, a type of bacteria found in soil and other environments.

The global health crisis of antibiotic resistance has led to increased interest in marine actinobacteria as a potential source of new, effective antibiotics.

“Actinobacteria have delivered many bioactive compounds some of which are now used as antibiotics and other medicines, such as anti-cancer and immunomodulating drugs,” Tammela told I nteresting Engineering (IE).

She further added: “The first clinically used antibiotic, after penicillin, that was discovered from actinobacteria was streptomycin, which was also the first drug effective against pulmonary tuberculosis.”

Hunt for microbes

While 70% of current antibiotics stem from soil actinobacteria, the vast majority of Earth’s environments remain untapped for antibiotic discovery. That’s why, the team decided to search for these novel molecules in the Arctic Ocean.

But they’re not looking for the traditional kind that kills bacteria outright. They’re searching for compounds that can reduce the bacteria’s ability to cause disease, or their “virulence.”

“Targeting virulence instead of killing bacteria, is investigated as one of the options to treat infections, and considered to have less risk for antimicrobial resistance, ” Tammela told IE.

They collected samples from the Arctic Ocean and tested them for antivirulence properties. For this, the team used sophisticated laboratory techniques to analyze extracts from marine actinobacteria.

After months of research, the team has made a breakthrough. They came across a natural compound that can inhibit the virulence of a dangerous strain of E. coli bacteria.

“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 explained in the press release.

New compounds

EPEC is a major cause of severe diarrhea, particularly in children under five. It attaches to the intestinal lining and injects harmful toxins into host cells, disrupting their normal cell function and leading to disease.

In this study, the compounds were extracted from four species of actinobacteria collected during a Norwegian research expedition to the Arctic Sea in 2020.

The isolated actinobacteria were cultured, extracted, and tested against EPEC in the lab setting.

“Most challenges were related to the samples, the lengthy process starting from culturing and extraction to fractionation and isolation,” Tammela told IE.

The screening process identified two previously unknown compounds with potent antivirulence or antibacterial activity. One compound was isolated from an unidentified strain of Rhodococcus, designated T091-5, while the other was obtained from an unidentified strain of Kocuria, labeled T160-2.

Among the two, the T091-5 compound is most promising due to its lack of effect on EPEC growth.

“These are very early findings, and the compounds will need to be studied much more before we know whether they are good candidates for therapeutic applications,” the author noted.

Tammela explained: “In our paper, we primarily aimed to demonstrate how beneficial advanced, phenotypic screening methods can be for discovering new antibiotic candidates and how they can be integrated to study marine natural products where the sample amount can be very limited.”

The findings were published in the journal Frontiers in Microbiology.