Genetic cross-talk lets bacteria fight back on antibiotics
A group of scientists from the UK have uncovered the bacterial system that allows antibiotic resistance to grow.
The new study sheds light on the sharing of genetic material between bacteria, which allows the spread of antibiotic resistance.
The mechanism that bacteria use to move substances across their cell wall is called ‘bacterial type IV secretion’, and researchers say that this distribution of genetic material between bacteria, antibiotic resistance included, is directly responsible for the spread of antibiotic resistance in hospital settings.
The newly-observed function also plays a crucial role in secreting toxins in infections - causing ulcers, whooping cough, or severe forms of pneumonia such as Legionnaires' disease.
Research has revealed that the type IV secretion system differs substantially from other bacterial secretion systems, in both its molecular structure and the mechanism for secretion.
“The entire complex is absolutely huge and its structure is unprecedented,” said Professor Gabriel Waxsman, from University College London.
“It is the type of work which is ground-breaking and will provide an entirely new direction to the field. Next, we need to understand how bacteria use this structure to get a movie of how antibiotics resistance genes are moved around.”
The studies were conducted on reconstructions of the system as observed in the bacteria E. coli.
The mechanism consists of two separate complexes; one in the outer membrane of the cell, and the other in the inner membrane. They are connected by a stalk-like structure that crosses the periplasm – the space between the two membranes. The complexes at both the inner and outer membranes form pores in the membrane, via which substances can be secreted.
Understanding the structure of the secretion system will help scientists uncover the mechanism by which it moves substances across the inner and outer membranes. It could eventually help develop new tools for genetic modification of human cells, as the bacteria could act as a carrier for genetic material to be secreted into cells.
“Understanding bacteria's secretion system could help design new compounds able to stop the secretion process, thereby stopping the spread of antibiotics resistance genes. Given that antibiotics resistance has become so widespread and represents a grave threat to human health, the work could have a considerable impact for future research in the field of antimicrobials,” said Professor Waksman.