Discussions on current research in biotechnology written in non technical language. My goal is to de-construct biotechnology topics so that they are palatable, exciting and informative for the layman. I feel passionate about the advancement of science for good. “Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.” ― Marie Curie
Dahlia, Butchart Gardens, Victoria, B.C.
Thursday 17 October 2013
What is a superbug?
A medical threat loosely termed “superbugs”
have been an increasing concern in modern healthcare. These are common
bacterial pathogens that have evolved to cause severe and antibiotic resistant
infections. Bacteria have naturally occurring mutations during DNA replication.
These mutations will often be detrimental to the organism; however,
occasionally the mutation may prove to be advantageous. For example, a mutation
may alter the target protein of an antibiotic rendering it resistant to that
antibiotic. When this occurs in a pathogen that is infecting a host subjected
to that antibiotic, the resistant organism may now flourish in the absence of nutritional
competitors. Other mutations may contribute to the organism producing factors
that cause a more serious infection.
Hospitals are a notorious site for the
emergence of superbugs for a number of reasons. Hospitals contain susceptible
and compromised hosts in close proximity. Patients admitted to the hospital may
carry drug resistant or highly virulent strains of bacteria. There are
antimicrobial agents being administered to the patients and used for
sterilizing equipment and surfaces. These are the agents that place
evolutionary pressure on the bacteria that can lead to the development of
resistant, hardy strains of the pathogen.
Incomplete antibiotic administration is also
a major contributor to resistance as it fails to completely eradicate a
normally susceptible strain. Low sub lethal levels of antibiotic give the
pathogen more time to adapt by allowing for cell division i.e. more cycles of
DNA replication and thus a higher chance of acquiring resistance.
Finally, many bacteria have developed
mechanisms to transfer antibiotic genes to neighboring bacteria through a
process called conjugation. They effectively send the DNA coding for resistance
over to their neighbor via a tube connecting the two cells. That means if your
normal flora that are not harmful carries antibiotic resistance genes there is
a chance that they may pass those genes along to harmful strains that cause
infection.
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