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Penicillin was a considered a medical miracle when it became available in 1943 during the WWII, rapidly crippling diseases caused by bacteria. But a few years later, micro-organisms that could resist it began appearing. Today, more and more patients every year suffer because of micro-organisms resistant to antibiotics. But researchers at the Department of Biotechnology at the Norwegian University of Science and Technology (NTNU) Trondheim are currently using genetic technology in an attempt to combat resistant strains of bacteria.

Antibiotic resistance

How do disease-causing microbes foil antibiotics? Resistant strains of bacteria withstand the effects of bacteria by meddling with their action mechanism. For instance, penicillin attacks bacteria by weakening and destroying their cell walls. The wall then raptures, killing the bacterium eventually. But resistant strains of bacteria either change their cell walls so that penicillin can’t interfere or make enzymes that will tear down the antibiotic.

Resistance to antibiotics is primarily due to gene action. Bacteria become resistant in three ways: spontaneous DNA mutation, microbial sex known as transformation, and resistance acquired from plasmid (a small circle of DNA). Drug-resistant tuberculosis arises when bacterial DNA mutate spontaneously and Pencillin-resistant gonorrhea is a result of transformation. In the resistance acquired from a plasmid, one type of bacterium quickly change to another type of bacterium. In fact, one plasmid can provide a number of different resistances.

Nystatin

Often, scientists find alternative types of antibiotics by searching in nature’s own chemist’s shop, which can be extremely costly and very time-consuming. Today, however, researchers at the NTNU attack the problem by using a more efficient and entirely different agent: recombinant DNA technology.

According to NTNU molecular genetics professor Svein Valla, the starting point in solving the problem is the antibiotic nystatin, generated from the Streptomyces bacterium and is presently used to treat fungal infections. For five years, Valla and his team of researchers have been working on this new method, which could become very important for the patients and the pharmaceutical industry.

The Streptomyces bacterium has about 8,000 genes - about 1% - 2% of which control how antibiotics form. This is the bacterium’s own defense mechanism against other microbes. With the recombinant DNA technology, scientists can now produce new forms of nystatin by isolating and altering nystatin genes and by putting these much sought-after  genes back in the original cell. Up to the moment, there’s no bacterial resistance to nystatin.

Source:

http://www.ntnu.no/gemini/2000-06e/40.htm

 

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