The treatment of bacterial infections using viruses, introduced
prior to the development of antibiotics in the 1940s, is gaining
interest.
UCLA researchers have come across a virus that can change the
protein it uses to attach to the bacteria it is infecting. The
bacteriophage is discussed in an article recently published in the
Sept. 23 issue of Nature magazine.
Since bacteria evolve new proteins or cell receptor molecules on
their surfaces, the viruses are not always able to attach at these
sites in order to infect the bacteria.
“A virus is already primed to evolve and this virus is
primed to overcome changes in the bacteria,” said Asher
Hodes, a graduate student in the Department of Microbiology,
Immunology and Molecular Genetics and a member of the research
team.
The virus attaches to the surface of the bacteria and injects
its DNA into the cell.
Once inside, the virus replicates and at the same time mutates
its DNA to change the protein used to attach to other bacteria.
Eventually, the bacteria can be destroyed.
Bacteriophage therapy, the use of viruses to destroy bacteria,
is currently used as treatment in parts of the world.
“With the increase in antibiotic resistance in both
hospital-acquired and community-acquired infections, it makes sense
to take a closer look at bacteriophages, which are essentially
nature’s antimicrobials,” said Jeffery F. Miller,
chairman of the MIMG department and head of the research team.
The ability of the Bordetella bacteriophage ““ the one UCLA
researchers worked with ““ to bind to different cell receptor
molecules was stumbled upon in the Miller lab two years ago.
“This serendipitous finding underscores the importance of
basic research,” said Anthony Fauci, director of the National
Institute of Allergy and Infectious Diseases, in the National
Institutes of Health News.
“With our increased understanding of how bacteriophages
work, we can potentially tailor these viruses to infect and destroy
bacteria that have mutated and become drug resistant.”
The ability for bacteriophages to quickly evolve alongside
bacteria is currently being studied by the UCLA research team to
better understand the mechanism.
“When nature comes up with a useful mechanism, she tends
to use it over and over again,” Miller said.
“Although we discovered the first member of the family in
a virus that infects bacteria, we now know it is widely distributed
in the bacterial domain of the tree of life,” he said.
The research, which was funded by the National Institutes of
Health, is focused on learning more about the mechanism these
bacteriophages employ.
“Although there are several important practical
applications, what really motivates us is the fact that these
genetic elements are fundamentally interesting, both
mechanistically and biologically,” Miller said.
Higher forms of life, such as bacteria, are being studied to see
if they possess the same mechanism that allows bacteriophages to
rapidly change a particular protein in its genetic code.
The bacteriophage is providing insight into treating
antibiotic-resistant bacterial infections.
“A virus is somewhat limited and specialized to a specific
bacteria,” Hodes said.
“But if you can evolve the virus to treat the bacteria
that you want to treat you can evolve an anti-bacterial drug that
will be useful clinically,” he added.