Team finds way to kill pathogen resistant to antibiotics

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Researchers developed a method that blocks a life-sustaining mechanism and kills an antibiotics-resistant bacterium that often spreads in hospitals.

The scientists primarily from Nagoya University’s Graduate School of Science said they targeted the mechanism of the bacterium, Pseudomonas aeruginosa, that ingests iron to maintain life.

An agent injected into the pathogen generates active oxygen when exposed to near infrared light, killing out Pseudomonas aeruginosa.

“Pseudomonas aeruginosa needs iron to proliferate,” said Osami Shoji, a bioinorganic chemistry professor at the university, who is a team member. “It will be difficult for the pathogen to become resistant to the method by abandoning the iron intake mechanism.”

Yuma Shisaka, a graduate student at Nagoya University, and others discovered that a pigment known as gallium phthalocyanine can attach itself to a protein that carries iron into the pathogen.

The scientists had Pseudomonas aeruginosa ingest the pigment, which is used as a paint for road signs and Shinkansen bullet trains, instead of iron. They then applied near infrared light to produce active oxygen, a chemical harmful to bacterium.

Pseudomonas aeruginosa can be found in water, soil and elsewhere, and it infects people with lowered immunity.

The team is looking to establish a treatment to deal with patients at medical centers whose lungs, eyes and other body parts are affected by the pathogen.

Existing therapies have proved ineffective because the bacterium is resistant to antibiotics and other substances that attack pathogens by preventing their cell walls from being formed.

Because of that, the World Health Organization cites Pseudomonas aeruginosa as one of pathogens for which antimicrobial drugs must be developed earlier than any other bacteria.

The team’s findings have been published in the online edition of the journal of the American Chemical Society at (https://pubs.acs.org/doi/10.1021/acschembio.9b00373).

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