Breakthrough in Antibiotic Discovery
For many years, there’s been a concern among researchers that the first wave of easily accessible antibiotics has been exhausted. This has put drug developers in a tough spot, searching for any small victories against a growing number of antibiotic-resistant bacteria. However, recent findings have revealed a potential game changer hidden in the soil.
A team of biochemists and pharmaceutical scientists from the U.S., Canada, and Germany has identified a new natural antibiotic, manikomycin, which is produced by the same unique soil bacteria responsible for oxytetracycline back in the 1950s. Early tests show that it is effective at combating at least one particularly resistant strain of pneumonia, known as Klebsiella pneumoniae, and introduces a new way for antibiotics to target bacterial infections.
What really piqued the interest of the researchers was the mechanism behind manikomycin. It zeroes in on the ribosomes within bacteria, disrupting their protein synthesis and preventing essential molecules from exiting these critical cellular structures.
As Dmitrii Travin, one of the study’s contributors from the University of Illinois Chicago, noted, “The ribosome is the target of about one third of all antibiotics prescribed currently.” He added that this antibiotic is remarkable because it targets a ribosome site that has never been affected by any other known compound.
Unearthing Potential
Technically speaking, manikomycin is classified as a peptide, which usually consists of chains of amino acids that play various roles in the body—acting as hormones or immunity enhancers, for example. Specifically, it falls into the category of “cationic antimicrobial peptides,” produced by various organisms, including soil bacteria like Streptomyces rimosus.
The teams from McMaster University’s antibiotic discovery center examined materials from 255 bacterial strains in their collection, seeking rare or overlooked natural antibiotics. Since life in the soil can be quite competitive, the ability of S. rimosus to produce antibiotics is vital for its survival.
Testing revealed that manikomycin was particularly effective against E. coli and resistant Klebsiella pneumoniae. The research found that only three or four of every ten billion E. coli bacteria managed to survive exposure to manikomycin. The survival rate for K. pneumoniae was slightly better, with about one in every hundred million enduring.
Researchers suspect that the unique method by which manikomycin impacts ribosomes leaves bacteria struggling to develop resistance.
As Alexander Mankin, an expert in antibiotics, explained, “Bacteria need to jump through hoops to find resistance.”
Looking Ahead
Derek Lowe, a medicinal chemist and pharmaceutical researcher who writes about drug discoveries, described manikomycin as an “excellent example” of a neglected compound that warrants further exploration. However, he also stressed that it shouldn’t be seen as a miracle drug, since it specifically targets a limited range of bacteria, notably struggling against many Gram-positive types, which includes common issues like staph infections.
Both Mankin and Travin acknowledged additional hurdles in translating these findings into a viable medication. They pointed out that manikomycin appears to break down quickly within the body, which is a significant concern.
As Mankin noted, “This antibiotic does not stay in the bloodstream long enough to effectively eliminate bacteria in humans or animals,” implying that improvements are necessary before it can be developed into a usable clinical treatment.
