Bacterial Resistance to Antibiotics.

Authors Avatar

Brad Godette

Bacterial Resistance to Antibiotics

November 15, 2002        

In our world of “quick fixes”, the rash use of antibiotics by doctors and their patients has resulted in a widespread problem of bacterial resistance to these drugs. Since penicillin was discovered, over 1,000 antibiotics have been invented (Novitt-Moreno 6).  The extended over-use and mistreatment of these drugs has led to rampant resistance.  Speaking from a strictly evolutionary point of view, the bacteria were forced both to evolve and adapt to this new situation or become extinct. Evolution is winning the battle against technology with the advent of “superbugs” which have become resistant to numerous antibiotics.  As outlined by Blazquez et al, antibiotics are selectors and promoters of antibiotic resistance in microorganisms (345).  This property creates a vicious cycle that can only be solved by a radical change in our research and development process of developing new antibiotics.

Probably the most well know example of antimicrobial resistance is the widespread resistance to penicillin.  In a span of three years, from 1941 to 1944, the bacteria Staphylococcus aureus developed penicillinase (now called β-lactamase), an enzyme that easily breaks down penicillin.  In contrast to 1941, when virtually every strain of S. aureus was susceptible to penicillin, today over 95% of S. aureus strains are resistant to penicillin, ampicillin, and the antipseudomonas penicillins (Neu 1065). Staphylococcus aureus can cause deadly infections of the skin, heart valves, blood, and bones, and in 1997, three Americans were reported to be infected with strains of it that were resistant to our last line of defense- the antibiotic vancomycin. Methicillin, a semisynthetic penicillin, was created to respond to this challenge.  However, in the 1980s, methicillin-resitant S. aureus (MRSA) became a problem as well.  Now, MRSA is resistant to all penicillins, cephalosporins, carbapenems, and penems due to a gene that produces a protein capable of bonding to and deactivating the penicillin (Neu 1065).

Antibiotics are mostly derived from natural products.  For example, penicillin is found in fungus; its discovery was actually accidental. After leaving some used culture plates unattended for several weeks, Dr. Alexander Fleming arrived back from his vacation to find fungus growing on them. On one plate, the Staphylococcus aureus bacteria that had been cultured there appeared to be inhibited by the fungus that had appeared. This fungus was found to be Penicillium notatum and everywhere it appeared on the plate, the bacterial growth was inhibited.  Although Dr. Fleming didn’t know what caused this phenomenon, his accidental discovery was an important step in creating antibiotics.

Join now!

Antibiotics are made to inhibit the growth of bacterial populations by stopping or disabling integral functions of the cell.  Many vital cell functions such as metabolic processes, biosynthetic pathways, energy transfer, motility, and the transport of substances are all dependent on enzymes. These proteins bind temporarily to one or more of the substrates of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction (Gale 25-26). Antibiotics often take advantage of this interplay between the enzymes and the dependent bacteria. Changing a single amino acid in an enzyme will ...

This is a preview of the whole essay