When Alexander Fleming accidentally discovered penicillin in 1928, the rate of death due to infectious diseases decreased dramatically, especially in developed countries. His
discovery led to the development and advancements in antibiotics. These drugs
effectively and economically fought off infectious diseases, but the abuse of
these “miracle” drugs pressured the bacteria to develop antibiotic resistances.
This blog will focus on
the antibiotics Streptomycin and Methicillin, and
how bacteria developed resistance to these drugs. The overall causes and
effects of antibiotic resistance will also be discussed.
Streptomycin
Streptomycin was discovered in 1943 as the cure to Tuberculosis(TB). TB is an infection caused by the bacteria Mycobacterium tuberculosis. This TB bacteria usually attacks the lungs but it can also infect the spine, kidneys and the brain. The first developed antibiotics, Penicillin and sulfonamides, had no effect on this bacteria. Its lipid-rich cell wall was making treatment impossible.
Aside from human use, streptomycin
is also used in agriculture. For instance it is used to fight against fire blight
in pome, pear and apple orchards. In the spring antibiotic sprays are sometimes
used to prevent infection. The Antibiotic is only used when the risk factor for
the disease is high. If the plant is already infected, the spray has no effect.
Overall, there are a lot of regulations on the use of streptomycin on plants in
America. The reason America doesn’t spray annually is because plant resistance
arose only five-ten years after its use in agriculture (Stockwell). The rest of
the world’s use of streptomycin is unknown due to politics
Methicillin
Methicillin was
developed in the late 1950s to deal with a penicillin resistant Staphylococcus
Aureus. This bacteria would cause lung and skin
infections. Early forms of penicillin had been overused by the public which
resulted in the antibiotic resistant bacteria. Staphylococcus aureus was
able to bypass penicillin’s beta-lactam attack by using an enzyme called
beta-lactamase (Penicillinase). This enzyme hydrolyzed the beta-lactam ring in
the penicillin making it lose its only effective mode of action. Penicillin cannot
destroy the bacteria’s cell wall using beta-lactum.
In response to this resistance methicillin was made. The
mode of action for this antibiotic was to inhibit ribosome function. Inhibiting
the ribosome would mean no protein production. Without proteins the cell could
not carry out simple functions and would die. This new drug became useless
in 1960, when Staphylococcus mutated and became Methicillin resistant. It had
gotten a gene that produced proteins that bonded to the antibiotic.This
interaction made the antibiotic ineffective. This new strain became known as Methicillin Resistant Staphylococcus aureus (MRSA). This
bacteria is still in an issue today but they are drugs that can help cure it.
The website MedicineNet.Com says that medical practitioners are being more
careful and using these new drugs as last resorts.
This bacteria
is still in an issue today but they are drugs that can help cure it. The
website MedicineNet.Com says that medical practitioners are being more careful
and using these new drugs as last resorts. Even though
there are rules in place, Staphylococcus was
able to develop resistance to a new drug called vancomycin. It has been dubbed Vancomycin Resistant Staphylococcus aureus (VARS). VARS could be the next
superbug, if it becomes widespread. Cases of VARS have increased over the
years.
This is Pamela Oglesby’s mother who
had to have her leg amputated because of MRSA. People who have had invasive surgery
have higher chance for MRSA infection. This was the case for Pamela’s mom. She
had surgery on her ankle and after a couple of weeks the incision sight began to
blister and her toes started turning black. After weeks of doctor visits she
finally got a culture of her wound. The culture ended up growing MRSA. The
doctors prescribed her antibiotics for nine months!! The antibiotics did
not work. Amputation was the only option left.
An article published by Nature.com discusses the appearance
of MRSA on pig farms. The antibiotics the pigs are being feed aren’t only used
to fight infections, but also to increase the size of the pig. “Studies have found that certain antibiotics can
increase pigs' growth rate by 2.5%” (Nature). This extra growth means
more profit which means more use of antibiotics. By pumping the environment
with antibiotics, we are forcing the bacteria to evolve quicker.
The pigs being feed antibiotics have developed MRSA due
to selective pressure. The MRSA thencan be picked up by the farmers handling
the pigs. It also manifests itself into our food sources which can become possible
ways for us to contract the infection. Uncooked meat or inappropriate handling
of the meat can lead to an infection. Another potential source is pig manure being
used as fertilizer. A study from the JAMA
Internal Medicine found that people who worked with pig manure were 38%
more likely to develop MRSA. The bacteria live in the pig’s feces making the
farmers more susceptible to the infection.
Despite the potential danger of antibiotics in
agriculture, many meat and agriculture industries are fighting against antibiotic
restrictions. Since these industries are wealthy they hold power in the
government through what is known as a Super PAC. A Super Pac draws out money
from unions and corporations to fund, or advocate against political candidates.
They suppress candidates who go against their best interests. The candidates
they help elect then go on to pass bills and laws that will benefit the Super
PACs that funded them. One agricultural Super Pac is “The Protect the Harvest Political Action Committee”.
There
are a few steps people can take to combat the use of antibiotics in agriculture:
1) Support PAMTA (the
Preservation of Antibiotics for Medical Treatment Act) and Senator
Diane Feinstein of California who is reintroducing the bill.
2)Pressure the FDA to apply Guidance #123. This is a draft
that aims to regulate agricultural companies use of antibiotics
3)The website NCPRIG allows you to send a message to FDA
Commissioner Margaret Hamburg. If enough people voice their concerns, the FDA
has to act.
4)Donate to NCPRIG. They fund and advertise for
candidates whose interests are your interests. They also eek educate other on
the issue at hand.
Here
are a few links of groups that help educate the general public about this
issue:
Miscellaneous Facts:
The threat of antibiotic resistance was apparent
since the discovery of penicillin. Alexander Fleming saw it and warned the
world ahead of time.
“Eighty percent of
antibiotics sold in the U.S. are used for animal agriculture” (PSR)
“Antibiotics are used to offset awful living
conditions in factory farms” (One Green Planet). Animals live in cramped places
filed with feces. These unsanitary conditions is what gets the animals sick in
the first place.
“last year two
million Americans suffered from illness and 23,000 died due to antibiotic resistant pathogens”(One Green
Planet).
Bibliography
1) http://pamela99.hubpages.com/hub/Infection-Caused-my-Mothers-Leg-Amputation
2) http://www.cdc.gov/mrsa/tracking/index.html
3)http://www.medicinenet.com/mrsa_infection/page6.htm#what_is_the_treatment_for_a_mrsa_infection
4) http://www.onegreenplanet.org/animalsandnature/5-alarming-facts-about-antibiotic-resistance-and-factory-farming/
5) http://www.cdc.gov/features/antibioticresistance/
6) http://www.cdc.gov/tb/topic/drtb/default.htm
7) http://www.oie.int/doc/ged/D11800.PDF
