Since antibiotics, such as penicillin, became widely available in the 1940s, they have been called miracle drugs. They have been able to eliminate bacteria without significantly harming the other cells of the host. Now with each passing year, bacteria that are immune to antibiotics have become more and more common. This turn of events presents us with an alarming problem. Strains of bacteria that are resistant to all prescribed antibiotics are beginning to appear. As a result, diseases such as tuberculosis and penicillin-resistant gonorrhea are reemerging on a worldwide scale (1).Resistance first appears in a population of bacteria through conditions that favor its selection. When an antibiotic attacks a group of bacteria, cells that are highly susceptible to the medicine will die. On the other hand, cells that have some resistance from the start or acquire it later may survive. At the same time, when antibiotics attack disease-causing bacteria, they also attack benign bacteria. This process eliminates drug-susceptible bacteria and favors bacteria that are resistant. Two things happen, populations of non-resistant and harmless bacteria are diminished, and because of the reduction of competition from these harmless and/or susceptible bacteria, resistant forms of disease-causing bacteria proliferate. As the resistant forms of the bacteria proliferate, there is more opportunity for genetic or chromosomal mutation (spontaneous DNA mutation (1)) or transformation, that comes about either through a form of microbial sex (1) or through the transference of plasmids, small circles of DNA (1), which allow bacteria to interchange genes with ease. Sometimes genes can also be transformed by viruses that can extract a gene from one bacterial cell and inject it into another (3). In this last situation, resistant genes become embedded in small units of DNA, called transpons, which can easily move into other DNA molecules. Making matters...
