A breach in the defense
Researchers from Rice University (USA), Texas A&M University (USA), Bayola University (USA) and Durham University (UK) have shown that molecular motors developed earlier are effective for the rapid destruction of antibiotic-resistant bacteria. Nanomotors target bacteria and, when activated by light, penetrate through the outer shell.
Nanomotors make the bacterial wall accessible to the antibiotic, restoring susceptibility to meropenem, to which resistance had previously developed.
Bacteria can mutate to resist antibiotics, but they have no protection from the molecular motors that drill holes in their shell. Antibiotics that can penetrate through these holes become deadly to bacteria again.
The group demonstrated molecular motors for drilling cells in 2017. They are molecules with branches in the form of blades, which, when activated by light, can rotate at a speed of three million revolutions per second.
In tests conducted in the laboratory of Texas A&M University, molecular motors effectively destroyed Klebsiella pneumoniae bacteria within minutes. Microscopic studies of target bacteria showed that the motors drilled holes in the cell wall, which is two lipid bilayers with inclusions of proteins and carbohydrates. Such a structure makes the outer shell impervious to antibiotics, but having penetrated through the holes made by nanomotors, antibiotics have again become capable of killing bacteria. It is noteworthy that they have no way to protect themselves from molecular motors, since they have a mechanical, not chemical effect.
The authors write that the combination of antibiotics with molecular motors will help defeat antibiotic-resistant infections and solve the global problem of multidrug resistance of pathogenic bacteria.
In bacterial colonies affected by a small concentration of nanomotors, up to 17% of cells died, but with the addition of the antibiotic meropenem, this figure increased to 65%. After selecting the optimal ratio of molecular motors and an antibiotic, the researchers achieved the death of 94% of the causative agent of pneumonia.
The authors write about the prospects of using molecular motors for the treatment of skin, wound, catheter or implantation infections caused by bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella or pseudomonas, as well as intestinal infections. The application is limited only by the possibility to introduce a light source that activates molecular motors. Another option is exposure to light on an external device through which human blood can be passed and returned to the body already with activated molecular motors in order to destroy the bacteria circulating in the blood. Bacteria that accumulate in the bladder and cause urinary tract infections can also be targeted by molecular motors.
Currently, researchers are engaged in improving the activation technology of molecular motors, which consists in replacing ultraviolet light with infrared. A shorter wavelength is safer for organs and tissues. Success in this direction will make it possible not only to expand the range of applications of molecular motors against bacteria, but also help to use them to fight cancer cells.
Article by T.Galbadage et al. Molecular Nanomachines Disrupt Bacterial Cell Wall, Increasing Sensitivity of Extensively Drug-Resistant Klebsiella pneumoniae to Meropenem is published in the journal ACS Nano.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on Rice University: Deadly 'superbugs' destroyed by molecular drills.