Antibiotics do not, in themselves, cause resistance. Instead, they allow naturally resistant variants within a population to survive and reproduce while those individuals without the resistance factor die. Once in a bacterial population, antibiotic resistance can spread rapidly. Even unrelated bacteria can gain resistance from their neighbors in a phenomenon called horizontal gene transfer (Reece, Simon and Campbell, 2010).
Resistance to antibiotics is encoded in DNA, the genetic blueprint for life. Bacteria are able to exchange DNA, especially in the form of plasmids (small, self-replicating circles of DNA) and pass resistance very rapidly.
An antibiotic kills a bacterial cell by simply disrupting a critical function. This is achieved in the cell in much the same way that a saboteur can cause a car to crash by simply cutting the brake lines. Antibiotic resistance of bacteria only leads to a loss of functional systems. Evolution requires a gain of functional systems for bacteria to evolve into man. The antibiotic binds to a protein so that the protein cannot function properly. The normal protein is usually involved in copying the DNA, making proteins, or making the bacterial cell wall—all important functions for the bacteria to grow and reproduce. If the bacteria have a mutation in the DNA which codes for one of those proteins, the antibiotic cannot bind to the altered protein; and the mutant bacteria survive (MacLean, 2010).
The Term Paper on Bacterial Dna Antibiotics Bacteria Antibiotic
... phage DNA matures within the cell, possibly carrying pieces of the bacteria s mutant chromosome. [8] Finally, there is transformation, involving mutated antibiotic-resistance genes ... STDs. In conjugation, a fine filament of protein called a plus reaches to another bacteria and pulls them together. The donor duplicates ...
In the presence of antibiotics, the process of natural selection will occur, favoring the survival and reproduction of the mutant bacteria. (The mutant bacteria are better able to survive in the presence of the antibiotic and will continue to cause illness in the patient.) Although the mutant bacteria can survive well in the hospital environment, the change has come at a cost. The altered protein is less efficient in performing its normal function, making the bacteria less fit in an environment without antibiotics. Typically, the non-mutant bacteria are better able to compete for resources and reproduce faster than the mutant form.
Quinolone-resistant bacteria have mutations in the genes encoding the gyrase protein. The mutant bacteria survive because the Cipro cannot bind to the altered gyrase (Reece, Simon and Campbell, 2010).
This comes at a cost as quinolone-resistant bacteria reproduce more slowly.4, 5, 6 Resistance to this family of antibiotics is becoming a major problem with one type of bacteria which causes food poisoning. This bacteria increased its resistance to quinolones 10-fold in just five years ( MacLean, 2010).
Bacteria can also become antibiotic resistant by gaining mutated DNA from other bacteria. Unlike you and me, bacteria can swap DNA. But this still is not an example of evolution in action. No new DNA is generated (a requirement for molecules-to-man evolution), it is just moved around. It’s like taking money from your left pocket and putting it into your right pocket—it doesn’t make you wealthier. This mechanism of exchanging DNA is necessary for bacteria to survive in extreme or rapidly changing environments like a hospital.
That means not asking for penicillin when all you have is a cold, since colds are caused by viruses that are not affected at all by antibiotics. It means taking all the pills that are prescribed, even if you’re feeling better. Physicians have to resist prescribing the strongest and most broadly effective drugs unless the disease absolutely requires it. If society adopts these measures rigorously, the drugs may regain at least some of their lost “miracle” powers.
The Term Paper on Antibiotic Resistance
Abstract The spread of antibiotic resistance is a universal threat to both humans and animals for treatment of microbial infections. The antibiotic resistance is generally not preventable but can still be controlled. Prolonged and repeated use of antibiotic leads to many pathogen becoming resistant to antibiotics. The resistance may be either intrinsic or acquired depending on the condition. ...
References
MacLean. (2010).
Discovery Medicine. The Evolution of Antibiotics Resistance: Insight into the Role of Molecular Mechanisms of Resistance and treatment context. Retrieved from http://www.discoverymedicine.com/R-Craig-MacLean/2010/08/04/the-evolution-of-antibiotic-resistance-insight-into-the-roles-of-molecular-mechanisms-of-resistance-and-treatment-context/
Reece, Simon and. Campbell Essential Biology with Physiology Vital Source eBook forEducation Management Corporation. 3. VitalSource Bookshelf. Pearson Learning Solutions, , Wednesday, February 22, 2012.
