Researchers at Harvard University, in the United States, have discovered a new class of antibiotic capable of killing Acinetobacter baumannii, a superbug resistant to the classes of drugs available to date.
“Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as an important global pathogen with limited treatment options. No new chemical class of antibiotic with activity against A. baumannii has reached patients in more than 50 years”, recall the researchers in an article published this Wednesday (3/12) in the journal Nature.
By analyzing a database with 44,985 molecules, scientists found zosurabalpine, a new class of small molecule antibiotics effective mainly against carbapenem-resistant A. baumannii (CRAB).
The antibiotic, developed in partnership with the Roche Group (Switzerland), was tested in infected laboratory dishes and in mice and was able to inhibit the growth of the bacteria in both.
A. baumannii has lipopolysaccharide (LPS) molecules in the outer membrane that prevent antibiotics from penetrating the cell. Zosurabalpine, in turn, acts on the LPS transport chain from the inner to the outer membrane of the bacteria (periplasm). The antibiotic binds to a protein complex in the bacteria’s membrane known as LptB2FGC.
By making this connection, the bacteria can no longer transport LPS, which ends up accumulating at toxic levels, leading to their death.
Resistant superbugs
Superbugs are a challenge to public health due to the high degree of resistance to antibiotics commonly used by doctors. This occurs when the strains no longer respond to conventional treatments. As a result, the patient suffers prolonged infections, with new hospitalizations.
The World Health Organization (WHO) estimates that more than 1 million people die every year worldwide from infections caused by bacteria resistant to antibiotic treatment.
A. baumannii is described by the WHO as one of the three most critical superbugs for health. It is so challenging that the US Food and Drug Administration (FDA) has not approved a new class of antibiotics to treat it in more than 50 years.