Drug
resistance is the problem of microbes developing resistance to drugs used to
treat the disease. This is caused by the misuse
of these agents for any infection, real or feared.Microbes are forced to adapt
or die ("selective pressure"). Hence, those microbes who survive reproduce to
produce offspring resistant to drugs.The microbes develop resistance because
the drugs which could overpower them were given too little or were stopped,
hence they can proliferate.The
problem is more important in bacteria who can transfer antibiotic resistance
to other non-resistant bacteria ,described below.
Antibiotic
Resistance in Bacteria
Bacteria
have developed means to destroy antibiotics used to kill them.One way is to
produce enzymes,i.e.: beta-lactamse which neutralizes penicillins and cephalosprins
by destroying their active component, the beta-lactam ring.Other bacteria can
pump antibiotics,e.g.:tetracycline out of their cell,rendering it useless. However,
bacteria can transfer such resistance to other bacteria.This is done through
three major ways, transformation,transduction and conjugation.
Transformation
Some
bacteria like Streptococcus pnemoniae,which causes pneumonia can "pick
up" DNA left behind by other dead bacteria and integrate it into their
own cells, combining traits of the dead bacteria with theirs.This creates a
new strain of bacteria and is known as transformation.Resistance traits left
by dead bacteria, in this way can be transferred to their bacteria.This process
is observed by Frederick Griffith in 1928 after he found that mice injected
with dead fatal bacteria and living harmless one died of pneumonia.He subsequently
found the harmless bacteria had possesed a coat from the dead fatal bacteria.
Transduction
Bacteria
like other celled organisms, can be infected by viruses known as phages.The
phages will integrate their genetic material into bacterial cells to produce
new viral progeny.The new viruses will then carry their parent's genetic material
and go on to infect another bacteria.However, this could go wrong and instead
of their parent's genetic material, the new viruses carry their host bacteria's
DNA instead and when another bacteria becomes infected, this
DNA is integrated to their own DNA and if it carries resistance traits, could
cause the new bacteria to become resistant.
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Conjugation
Bacteria
have a special ability of sharing genetic infomation.One donor bacteria will
extend a genetic bridge(pilli) to recipient bacteria and some genetic information
in small-ringed packages called plasmids will be copied and transferred to the
recipient bacteria.This method can take place between two species of bacteria,
hence it is the most important method in resistance transfer.
Conclusion
The
only way to stop resistance is to use antibiotics wisely so that all bacteria
will be killed.This can be done by everyone.Complete antibiotic courses even
though you may feel well and do not take antibiotics for any viral infection
as they are useless to viruses.Through prudent use of antibiotics and other
anti-microbial drugs, resistance can be stopped and mankind would not live in
an era where no drugs could be used against microbes and millions die of disease.