Antibiotic resistance



Antibiotic resistance is the ability of certain bacteria to remain unaffected by antibiotics, which would normally kill them. Bacteria can have antibiotic resistant genes passed down to them or obtain antibiotic resistance from mutations or an exchange of genetic information with other bacteria. A population of bacteria can develop antibiotic resistance because the bacteria that is able to fight the drug can survive and reproduce. Antibiotics were first discovered in the 1920s by Alexander Fleming. Ever since people began using penicillin, the first antibiotic used to treat humans, in the 1940s, antibiotic resistance has spread. Thousands of people die each year from infections caused by resistant bacteria.

Evolutionists use the existence of antibiotic resistant bacteria to support their theory and claim that the bacteria shows how mutations and natural selection work to form types of organisms better equipped for survival. However, antibiotic resistance in bacteria does not prove that any organism can evolve into a new kind of organism. In fact, in the absence of antibiotics, most of the mutations that cause antibiotic resistance will actually decrease the bacteria's overall fitness.

History and Examples of Antibiotic Resistance
Antibiotics can be the chemicals made naturally by microorganisms to kill bacteria or synthetic compounds that accomplish the same function. They were discovered in 1928 by Alexander Fleming. This resulted in the production of penicillin in the 1940s. However, later in that same decade bacteria started to develop resistance to the antibiotics. Since then, bacteria have become increasingly resistant to the drug. Now, 70 percent of bacteria responsible for infections in hospitals have some form of antibiotic resistance.

Since this time, many different kinds of antibiotic resistant bacteria have come into existence. Some examples of this include Staphylococcus aureus and Neisseria gonorrhoeae. Although these types of bacteria used to be treated by benzyl penicillin, they are no longer greatly affected by the antibiotic. Many types of bacteria can resist several of the major kinds of antibiotics. These include Staphylococcus aureas, which can resist methicillin and penicillin, and Enterococcus, which has a resistance to vanomysin. Other species of bacteria, such as Klebsiella pneumoniae carbapenemase-producing bacteria and Mycobacterium tuberculosis are also insusceptible to multiple antibiotics.

How Antibiotic Resistance Occurs
Bacteria can either inherit antibiotic resistance or acquire it by changes in their DNA. This is caused by mutations or by having the DNA transferred to them from other bacteria. The latter occurs in a process called horizontal gene transfer or conjugation and involves the use of plasmids and transposons, which carry genes from one bacterium to another. These bacteria can repel antibiotics by forming enzymes that neutralize them, quickly expelling them from the cell through efflux pumps, preventing the antibiotics from attacking at sites where they can significantly harm the bacteria using ribosome protection proteins, or by lacking the ability to absorb the antibiotics through their membranes. A bacterium can accumulate resistance genes that allow it to survive many types of antibiotics.

A population of bacteria can become resistant because of natural selection. First, the bacteria must be subjected to antibiotics. This could be in high amounts from antibiotics produced by humans or in lower amounts from ones made by other bacteria. Antibiotics will eventually kill the susceptible bacteria. After these bacteria die, the resistant bacteria will be left behind to reproduce. This increases the total percentage of bacteria not affected by the drug.

Often, antibiotics are prescribed and utilized incorrectly. Sometimes people even use them against infections caused by viruses, even though antibiotics can only kill bacteria. Because of this frequent use of antibiotics, bacteria continue to become resistant and the drug loses its effectiveness.

Problems Caused By Antibiotic Resistant Bacteria
Antibiotic resistant bacteria pose a great problem for those working in the medical field. Two million people are infected by resistant bacteria each year in the United States, and 23,000 die because of them. Certain diseases caused by pathogens known as "superbugs" no longer respond at all to antibiotics. Because of this, more people might perish from these illnesses and treatment may become more expensive.

One important way stop bacteria from becoming resistant appears to be to only prescribe and take antibiotics when they are actually needed. Patients must also be careful to use antibiotics correctly by taking the whole course of antibiotics instead of stopping once they no longer feel the symptoms of the infection. One can become infected with resistant strains of bacteria after touching people or surfaces that contain the germs. People can prevent this by practicing good hygiene. Doctors can help by having clean hands, using gloves and masks, and properly disposing of needles. Everyone should regularly wash their hands, cover their mouth when they sneeze, and cook meat carefully in order to stop the spread of antibiotic resistant bacteria.

Significance in the Creation vs. Evolution Debate
According to the Theory of Evolution, changes in an organism's genes (called mutations), together with natural selection, are responsible for the evolution of new kinds of organisms. New genetic information would be necessary for new kinds of organisms to arise. Evolutionists believe that mutations served as the mechanism that provided these genetic changes and that the mutant organisms were better able to survive and pass on their characteristics to future generations. They use antibiotic resistant bacteria as their main example of how mutations can produce organisms with a higher likelihood of survival.

However, antibiotic resistance does not prove that mutations are able to create genetic information. First of all, some antibiotic resistance genes occur normally in bacteria, but simply have increased expression or are present at a higher rate in resistant bacteria. For example, a species of bacteria called Streptomyces naturally possesses the genetic information to form efflux pumps and ribosomal protection proteins as a defense against the antibiotics it produces. This means that these bacteria are not acquiring or evolving new characteristics at all; they are simply expressing traits that are already part of their genome. In a study published in 2011, researchers from McMaster University (Hamilton, ON) and the University of Alberta presented evidence that antibiotic resistance genes were present in bacteria before humans started using antibiotics. By performing metagenomic analyses on permafrost sediments from the Yukon Territory, they detected the antibiotic resistance genes vanX, tetM, and bla. They also detected mammoth DNA, confirming that the sediments predated human use of antibiotics.

Sometimes a bacterium will obtain antibiotic resistance through mutations. These new mutations may change the shape of the ribosomes or proteins in the bacterium, preventing antibiotics from attaching to them. However, the structures changed by the mutation often will not work as well as normal ones. The populations of mutated bacteria may have difficulty producing proteins and growing. For instance, some bacteria are unaffected by the antibiotic quinolones because of a mutation that alters the protein gyrase. However, this mutation also causes the bacteria not to multiply as quickly. This means that the resistant bacteria will not survive as well as other bacteria when antibiotics are not present. In addition, the mutations that allow antibiotic resistance cause a loss or decrease of certain structures or processes found in bacteria. They do not illustrate how the genetic information that causes these functions in bacteria originated. Antibiotic resistant bacteria demonstrate genetic variability in a population, but they do not provide support for macroevolution.

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Additional info

 * The "Evolution" of Antibiotic Resistance by Daniel Criswell, Ph.D. ICR Impact 378. December 2004.

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