CRAB is the name of a type of bacteria that can cause dangerous infections in the blood, lungs, and urinary tract, according to the U.S. Centres for Disease Control and Prevention. A group of strong medicines called carbapenems can’t kill it, which is a bad thing.

Researchers from Harvard University and the drug company Hoffmann-La Roche found that zosurabalpin, a new type of antibiotic, can kill A. baumannii in a study that came out on January 3 in the journal Nature.

Dr. Kenneth Bradley, global head of infectious disease discovery at Roche Pharma Research and Early Development and researcher, told CNN that Zosurabalpin works in a way that isn’t like anything else on the market.

His explanation was that this was a new way to do things, both in terms of the compound itself and the way it kills germs. It is hard to fight A. baumannii because it is a Gram-negative bacteria, which means it has protective membranes on both the inside and the outside.

Scientists first tried to find a molecule that could get through those double membranes and kill the germs. Then, they worked on making it even better.

Researchers picked one changed molecule after working for years to make many compounds stronger and safer.

How does it do its job? Zosurabalpin stops lipopolysaccharides, which are big molecules, from moving to the outer membrane of bacteria. There, they keep the protected membrane intact. This makes the molecules build up inside the bacteria cell until the cell becomes so poisonous that it dies.

More than 100 CRAB samples were used in the study, and zosurabalpin worked on all of them. It also lowered the amount of bacteria in mice that had asthma caused by CRABs and kept mice from dying of sepsis caused by the bacteria.

Researchers told CNN that Zosurabalpin is now being tried in phase 1 clinical trials to see if it is safe for people to use.