Deadly superbugs killed by molecular drills.


Antibiotics are medicines used to prevent and treat bacterial infections. Antibiotic resistance occurs when bacteria adapt in response to the use of these medicines and become immune to their mode of action, making them harder to treat. Bacteria are becoming increasingly resistant to antibiotics, with work concentrating on the mechanisms these bacteria use to adapt to the various modes of antibiotics. Now, a study from researchers led by Rice University develops motorized molecules that can target and drill through antibiotic-resistant bacteria and kill them within minutes. The team states the molecular drills, which are light-activated, can open bacteria to attack by drugs they previously resisted. The study is published in the journals ACS Nano and ACS Applied Materials Interfaces.

Recent studies from the team developed motorized molecules that were driven by light to drill holes in the membranes of individual cells. It was shown that rotors in these single-molecule nanomachines, which were so small 50,000 of them could fit across the diameter of a human hair, could be activated by ultraviolet light to spin at 2 to 3 million rotations per second and open membranes in cells and kill them. The current study uses motorized nanobots to drill into drug-resistant bacterial cell walls and increase susceptibility to recently ineffective antibiotics.

The current study develops paddlelike molecules designed to be drills that can spin at 3 million rotations per second when activated with light. The nanomotors were then used to attack the drug-resistant Klebsiella pneumoniae, a rod-shaped bacterium that can cause a host of infections including pneumonia, meningitis, and sepsis. Results show the synthetic molecular drills effectively kill K. pneumoniae within minutes with microscopic images showing where they drilled through its cell walls.

Data findings show the nano-drills increase the susceptibility to Meropenem, an antibiotic, effectively killing K. pneumoniae that are considered Meropenem-resistant. The lab explains that bacteria have extremely robust cell walls with two bilayers and proteins with sugars that interlink them, which makes them so difficult to penetrate and kill. They go on to add that the bacteria in this experiment had no way to defend against their molecular drills as this is a mechanical action and not a chemical effect.

The team surmises they have engineered synthetic molecular nanomachines that have the ability to open drug-resistant bacteria cell membranes using a nanomechanical action. For the future, the researchers state their strategy could be applied to treat bacterial infections or diseases on the skin, in the lungs or in the gastrointestinal tract.

Source: Rice University

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