Bacteria develop resistance to antibiotics

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wikimedia commons

One of the greatest medical achievements of all time is considered to be the discovery and isolation of antibiotics. They have become associated with technological progress and have become a symbol of human ingenuity.

In 1943, penicillin was first used to treat wounded soldiers and by 1946 it cost 55 cents per dose. Penicillin was cheap, safe to take and was considered to be a “magic bullet.”

Ever since their discovery, antibiotics have been considered a miracle drug capable of curing anything the world of disease could throw at it. The media, the public and the scientific community could not have been more wrong.

It is important to understand that medicinal antibiotics have only been around for about 80 years. Within that time frame, the genetic development of millions of bacteria, viruses, archaea, parasites and fungi have been drastically altered with the introduction of medicinal antibiotics.

Since medicinal antibiotics are a relatively recent phenomenon, there is still much which is not understood about their long term impact on the microbial world. The entire world around us is covered in microbes, from the paper or screen on which you are reading this to the skin on your body. It is a “micro universe” filled with exotic life forms that live together in community.

However, in order for these communities to survive and evolve, they must be able to protect themselves and their fuel sources.  Most microbes have a chemical defense system made up of small proteins called defensins. Defensins are an example of naturally occurring antibiotics that most microbes use.

Whenever we hear about antibiotics in the press, we hear about laboratory produced antibiotics that have been formulated for medicinal use, such as the common penicillin variant, amoxicillin. The story is usually set up so that there is a horrible bacterium that is going to destroy the world and that the valiant antibiotic is going to destroy it.

Popular media makes it seem like antibiotics are smart bombs that selectively target and destroy the bad bacteria and leave the good cells around them alone.  In reality, most antibiotics are like indiscriminate nuclear bombs that wipe out whole populations of bacteria — both good and bad — and leave behind debris and poisonous chemicals.

Before I progress any further I want to establish that there is such a thing as good bacteria. For example, the human gastrointestinal tract is loaded with bacteria that enable us to digest our food and gain nutrients. Without these bacteria, we would not be able to properly digest our food and would suffer severe medical problems.

About 98 percent of bacteria that come into contact with the human body each day are not harmful to us; in many cases these bacteria are beneficial to us, such as the bacteria in the intestines. When you take antibiotics when you are sick, the antibiotic does not seek out and destroy only the harmful bacteria, but it destroys many of the bacteria that it comes in contact with, including bacteria that are beneficial to the body.

After the antibiotic treatment has concluded, the surviving bacteria in the body begin to multiply and fill the old spaces where the dead bacteria used to be. The result is a new community of bacteria. New genes will be exchanged among cells, and if there are any of the harmful bacteria that were somehow resistant to the antibiotic, these resistant bacteria can now increase in number. This is how antibiotic resistant bacteria such as Menicillin Resistant Staphylococcus aureus (MRSA) have developed.

Over the past 20 years, antibiotics have surged in their prescription rate and sometimes are even used as marketing gimmicks to parents of young children, such as in antibiotic covered play sets. The rate of antibiotic resistant pathogens has correlated with the surge in the applications of antibiotics.

There is a natural balance of power within the microbial world between microbes, and in some cases where antibiotics are overused, this balance of power between the microbes is disrupted.

Scientists have taken notice of the alarming number of antibiotic resistant organisms and are trying to both formulate new antibiotics and to contain the spread of antibiotic resistant organisms. Hospitals have become ground zero for antibiotic resistant bacteria including the bacterium responsible for the highest number of hospital acquired infections, Clostridium difficile.

A new strain of Clostridium difficile has recently emerged that is resistant to some of the more powerful antibiotics, such as ciprofloxacin and levofloxacin. The CDC recently released a threat report warning of the increase in antibiotic resistant bacteria, focusing on improving medical and healthcare practices to combat the spread of disease.

However, it is important that everyone understand that they too can help prevent the spread of disease by practicing good hygiene, taking a day off from work or school when sick and keeping up on vaccines for bacterial infections. Antibiotics are sometimes very necessary and can be lifesaving, so it is important not to forget this. However, too much of a good thing can be unnecessary and, in the case of antibiotics, harmful.

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