Researchers at the Hebrew University of Jerusalem have reached a breakthrough in understanding how "persistent bacteria" withstand treatment with antibiotics.
They report their work, which could pave the way for new ways to control such bacteria, in the journal Nature Communications.
Unlike drug-resistant bacteria that have evolved their ability to resist antibiotics through mutation, persistent bacteria do not resist the drugs but simply lie dormant or inactive while exposed to them. Then, when the treatment is over, they "wake up" and continue with their harmful activity.
It is the bacteria's ability to lie dormant and then wake up once the threat to them had passed that has puzzled scientists.
Some clues exist, such as evidence of some kind of link between persistent bacteria and HipA, a toxin that occurs naturally in them.
But until this new study - which was led by two Hebrew University professors, Gadi Glaser, of the Faculty of Medicine, and Nathalie Balaban, of the Racah Institute of Physics - it was not clear what activated HipA and how it might trigger dormancy in the bacteria.
When treatment stops, the bacteria wake up
The team showed that when antibiotics attack the persistent bacteria, the HipA toxin plays havoc with the chemical signals that the bacteria cells use to build proteins from nutrients.
Consequently, the bacteria interpret this disruption as a "hunger signal," which in turn triggers an inactive, dormant state. And so the bacteria stay "asleep" until the treatment is over. When it is, HipA stops disrupting nutrient use, and the bacteria wake up and resume their normal - harmful - activity.
Prof. Balaban's lab has been working on persistent bacteria for some years, to try and better understand their biophysical properties.
Now, that knowledge and the findings from this study - combined with other work that has been going on in Prof. Glaser's lab - should result in a big push forward in the fight against persistent bacteria.
In another study published in the Journal of Bacteriology in 2013, researchers reported how they are beginning to defeat hospital-associated persistent bacteria infections.