Antibiotic resistance makes it difficult to fight infection and
increases the chance of acquiring one while in a hospital. That, in
turn, has led to more deaths from infection( longer hospital stays
and a greater use of more toxic and expensive drugs can be the reason of
infection according to
the National Institutes of Health in most cases)
Resistance occurs when bacteria develop ways to make themselves impervious, such
as by pumping antibiotics out of the cell, preventing them from entering the
cell
or demolishing them. A common way bacteria develop resistance is by
laterally transferring plasmids -- pieces of extra-chromosomal DNA --
from one bacterium to another. These plasmids contain genetic codes
for proteins that make bacteria insensitive to antibiotics.
Hergenrother thought that if you could eliminate plasmids that make
the bacterium resistant, then the bacterium could be sensitive to
antibiotics again.If there is one plasmid in a cell and another one
is introduced, then they compete with each other for resources.One
of them wins and the other is eliminated.(This is natural phenomenon
called as plasmid incompatibility.)
With the help of chemistry graduate students Johna C.B. DeNap, Jason
R. Thomas and Dinty J. Musk, Hergenrother developed a technique that
mimicked plasmid incompatibility by incubating bacteria containing
plasmids with a specific compound -- in this case an aminoglycoside
called apramycin that binds to plasmid-encoded RNA and prevents
proper plasmid reproduction. Apramycin was chosen after numerous
potential aminoglycosides -- a group of antibiotics effective
against gram-negative bacteria -- were tested to find those that
bind tightly to the target plasmids. Positively charged apramycin
bound to negatively charged plasmid-encoded RNA, which allowed
apramycin to prevent the actions of the protein that triggers
plasmid reproduction. By thwarting that protein, apramycin blocked
plasmid replication.
Short keys:
Drug resistant bacteria aparamycin plasmid
incompatibility
Sensitivity resumed.
Reference: http://www.brightsurf.com/news/nov_04/EDU_news_111504.php