Bacterial Killer Novel antibiotic found in tree bugs

Tree bugs are the saviors in the antibiotic crisis?

Tree bugs produce a bactericidal substance, which is the basis for completely new antibiotics. Researchers from Switzerland have deciphered a previously unknown mechanism that protects beetles from bacteria. This mechanism could be used to kill antibiotic-resistant bacteria.

A research team from the University of Zurich (UHZ) investigated the natural substance thanatin produced by tree bugs, which is able to destroy the outer membrane of certain bacterial groups and thus kill the germs. The researchers were able to decipher the underlying mechanism for the first time. On this basis, one can develop novel antibiotics that act completely different and thus avoid resistance. The study results were recently published in the journal "Science Advances".

Tree bugs produce the natural antibiotic thanatin, which uses a novel mechanism to kill certain types of bacteria. (Image: evbrbe / fotolia.com)

One of the biggest threats of the 21st century

Antibiotic resistance is increasing dramatically worldwide and is a growing threat. The World Health Organization (WHO) recently warned that 700,000 people are already dying from resistant bacterial infections each year. These infectious diseases were well curable with antibiotics before the resistance spread. Against this backdrop, researchers worldwide are working on new solutions to circumvent these resistances.

New antibiotic classes from insect production

"Despite intensive efforts by science and industry, it has not yet been possible to find suitable targets for novel antibiotics," said John A. Robinson of the Institute of Chemistry of UZH in a press release on the study results. This could change now: According to the researchers, the tree bomber substance Thanatin destroys the outer shell of Gram-negative bacteria. These are a group of bacteria that have a thin, single-layered membrane.

Many pathogens belong to the gram-negative bacteria

"This group of germs includes many dangerous pathogens such as Pseudomonas aeruginosa, which causes life-threatening lung infections, as well as pathogenic strains of the intestinal bacterium Escherichia coli," explains Robinson. Disease-causing intestinal bacteria cause severe infectious diseases with diarrhea as the leading symptom, such as EHEC infection.

Without a protective shield, the bacteria are stuck

As the research team reports, the natural antibiotic thanatin from the North American tree bug Podisus maculiventris destroys the outer cell membrane of Gram-negative bacteria. This membrane acts like a shield that protects the cell from toxic substances. Without this protective cover, the bacteria are helplessly exposed to their environment and die.

How does Thanatin destroy the bacteria shield??

According to the researchers, the protective outer layer of the bacteria consists of a complex layer of fat-like and sugary substances. These substances are called lipopolysaccharides. Thanatin disrupted the transport of the building blocks needed to build the outer membrane, experts said. The affected transport route consists of a structure of seven different proteins, which form a kind of bridge on which the building materials are led to the cell envelope. "Thanatin blocks the interaction between the bridge proteins, thereby preventing the formation of the bridge structure," explains the UHZ research team.

Totally new way of fighting bacteria

"This mechanism of action is so far unprecedented and opens new perspectives for the development of future antibiotic classes against dangerous germs," ​​sums up Robinson. This is the first proof that the inhibition of interactions between proteins is suitable for killing bacteria.

The active ingredient should be quickly brought into the next phase

Currently, the research team and an experienced industry partner are seeking suitable candidates for a clinical trial. "A novel antibiotic targeting Gram-negative pathogens would be an important complement to the development of much-needed antibacterial therapies," concludes Robinson. (Vb)