Researchers at Nagoya University in Japan have managed to kill bacteria that have developed drug resistance by hijacking the system they usually use to grow.
“Super bacteria” that resist the most powerful antibiotics: this is one of the health threats that hangs over humanity today.
Already responsible for 33,000 deaths a year in the European Union, antimicrobial resistance could, according to a report from 2014reaching 10 million deaths per year each year in 2050.
Among these potentially deadly bacteria that have developed multi-drug resistance is Pseudomonas aeruginosa. Considered by the World Health Organization (WHO) as one of the most dangerous pathogens, it is particularly present in hospital settings, where it is likely to cause blood infections and pneumonia in people whose system immune is weakened.
Its particularity: like other “super bacteria”, it secretes a protein called HasA which clings to the heme acquisition system present in the blood of its host. This allows it to obtain iron, an essential trace element for its growth. This HasA protein secretion complex is recognized by a bacterial membrane receptor called HasR, which allows heme to enter the bacterial cell, while the HasA protein is recycled to recover more iron.
A “Trojan horse” that destroys bacteria from the inside
However, this mechanism could be abused. This is what researchers from Nagoya University in Japan have managed to do. In a study published online at ACS Chemical Biologythey explain that they managed to kill the bacteria Pseudomonas aeruginosa by hijacking their heme acquisition system, which allowed them to administer antimicrobials to them.
To achieve this, they developed a powder made up of the HasA protein and a gallium phthalocyanine (GaPc) pigment which, applied to a culture of Pseudomonas aeruginosawas consumed by bacteria.
“When the pigment is exposed to near-infrared light, harmful reactive oxygen species are generated inside the bacterial cells,” says Osami Shoji, lead author of the work. During the tests, more than 99.99% of the bacteria were thus killed thanks to this treatment and ten minutes of irradiation.
The strategy also worked on other bacteria with the HasR receptor on their membranes, the researchers explain.
“Our results support the use of artificial heme proteins as a Trojan horse to selectively deliver antimicrobials to target bacteria, enabling their specific and effective sterilization, independent of antibiotic resistance,” the team reports in their study, who hopes that this strategy may work on other multiresistant bacteria.
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