Punching a hole in bacteria

As bacteria gain resistance to our antibiotic armoury, medical scientists are earnestly hunting for alternatives to the many overused drugs. Now, Reza Ghadiri and colleagues at the Scripps Research Institute in La Jolla, California, believe they have found one solution to the problem.

Ghadiri and his colleagues have focused on peptides since the early 1990s. Among the peptides, chains of amino acids, are many produced by various plants and animals to combat bacterial infection. Their use as antibiotic drugs for people, however, would at first sight seem rather limited as they are large molecules and cannot be transported to the site of infection.

Staphylococcus aureus

So, the Scripps team has turned to a synthetic peptide that acts as a powerful antibiotic that circumvents the transport system problem by ringing the changes. The team has synthesized rings of alternating D and L amino acids, which stack up by self-assembly to form tubes that lock into the bacterial cell wall.

These peptide nanotubes simply pull the plug on a bacterium, allowing its innards to spill out and so killing it. According to the team their peptides cleared infections of the antibiotic-resistant microbe Staphylococcus aureus in mice even when injected far from the site of infection. According to Thomas Ganz of the University of California, Los Angeles School of Medicine this is an "exciting advance" in the quest for new antibiotics.

Nature, 2001, 412, 452-455