Research in Israel may open the door for future treatments that are an alternative to antibiotics, in the fight against drug-resistant bacteria.

The researchers at the Weizmann Institute of Science, in Rehovot, discovered that human cells can naturally produce compounds that can kill bacteria and fight severe bacterial infections in mice.

Antibiotic resistance is a growing public health crisis, responsible for more than one million deaths each year due to infections caused by drug-resistant bacteria.

The team found that the proteasome – a cellular waste disposal system responsible for breaking down and recycling damaged or unnecessary proteins, that is present in all living organisms – plays a direct role in the immune system.

Their findings showed that the proteasome generates small protein fragments, known as proteasome-derived defence peptides, capable of killing bacteria that cause severe infections.

These naturally occurring defence peptides were injected into mice with pneumonia and sepsis, both life-threatening infections often caused by drug-resistant bacteria. This successfully destroyed the bacteria and improved survival rates of the infected mice – effects that are comparable to those of commonly used antibiotics.

The study, in Nature, also showed that the infections themselves also made the proteasome  even more effective in producing the defence peptides.

Lead researcher, Yifat Merbl, said: “We saw that infection causes the proteasome to change its protein-cutting mode, ‘favouring’ the production of peptides with antibacterial properties.”