Experimentally Induced Resistance to Nalidixic Acid in Bacillus subtill

Experimentally Induced Resistance to Nalidixic Acid in Bacillus subtillis does not Result in Resistance to other Antibiotics Introduction: In the environment, bacteria frequently encounter various antibiotics and through various mechanisms, evolve to become resistant to these antibiotics. Some of these mechanisms sometimes involve beneficial mutations in a bacterium that allow it survive antibiotics but more frequently involve a transfer of genes from other bacteria, even bacteria of different species. Through the transfer of genes from other bacteria, a bacterium can acquire resistance against several antibiotics (Levy 2002). Nalidixic acid is commonly used to treat urinary tract infections (Nalidixic Acid (Systematic) 1999), and is thus found in concentrated amounts in urine. When a person urinates, any excess nalidixic acid can easily find its way to soil, where Bacillus subtilis is found naturally. As the nalidixic acid would be diluted to sub-therapeutic concentrations, all the nalidixic acid would do is to select for resistant strains of any bacteria (e.g. B. subtilis) encountered (Levy 2002). As bacteria can pass along resistance factors to other currently un-resistant bacteria, the harmless B. subtilis which harbors resistance factors against nalidixic acid can potentially pass the resistance factors to harmful bacteria. Bacteria, however, frequently develop resistance not only to one antibiotic but to several and can pass on resistance factors for all these antibiotics to other bacteria. This study will attempt to produce B. subtilis that is resistant to nalidixic acid and determine if these nalid ixic acid-resistant B. subtillis are also resistant to other antibiotics, especially those in the same class. ... ...important not to lose its effectiveness to antibiotic resistance. References: Ciprofloxacin (Oral) [Internet]. Medline Plus Health Information, US National Library of Medicine, National Institutes of Health; [updated 2003 Apr 3; cited 2003 Apr 5]. Available from: http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a688016.html Levy, S. B. 2002.The Antibiotic Paradox: How the Misuse of Antibiotics Destroys Their Curative Powers. Perseus Publishing, MA. Hardy, S. P. 2002. Human Microbiology. Taylor and Francis, NY. Nalidixic Acid (Systematic) [Internet]. Medline Plus Health Information, US National Library of Medicine, National Institutes of Health; [updated 1999 Jun 14; cited 2003 Mar 6]. Available from: http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202387.html Voyles, B. A. 2003. Personal communication. Antimicrobial Susceptibility Testing. Experimentally Induced Resistance to Nalidixic Acid in Bacillus subtill Experimentally Induced Resistance to Nalidixic Acid in Bacillus subtillis does not Result in Resistance to other Antibiotics Introduction: In the environment, bacteria frequently encounter various antibiotics and through various mechanisms, evolve to become resistant to these antibiotics. Some of these mechanisms sometimes involve beneficial mutations in a bacterium that allow it survive antibiotics but more frequently involve a transfer of genes from other bacteria, even bacteria of different species. Through the transfer of genes from other bacteria, a bacterium can acquire resistance against several antibiotics (Levy 2002). Nalidixic acid is commonly used to treat urinary tract infections (Nalidixic Acid (Systematic) 1999), and is thus found in concentrated amounts in urine. When a person urinates, any excess nalidixic acid can easily find its way to soil, where Bacillus subtilis is found naturally. As the nalidixic acid would be diluted to sub-therapeutic concentrations, all the nalidixic acid would do is to select for resistant strains of any bacteria (e.g. B. subtilis) encountered (Levy 2002). As bacteria can pass along resistance factors to other currently un-resistant bacteria, the harmless B. subtilis which harbors resistance factors against nalidixic acid can potentially pass the resistance factors to harmful bacteria. Bacteria, however, frequently develop resistance not only to one antibiotic but to several and can pass on resistance factors for all these antibiotics to other bacteria. This study will attempt to produce B. subtilis that is resistant to nalidixic acid and determine if these nalid ixic acid-resistant B. subtillis are also resistant to other antibiotics, especially those in the same class. ... ...important not to lose its effectiveness to antibiotic resistance. References: Ciprofloxacin (Oral) [Internet]. Medline Plus Health Information, US National Library of Medicine, National Institutes of Health; [updated 2003 Apr 3; cited 2003 Apr 5]. Available from: http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a688016.html Levy, S. B. 2002.The Antibiotic Paradox: How the Misuse of Antibiotics Destroys Their Curative Powers. Perseus Publishing, MA. Hardy, S. P. 2002. Human Microbiology. Taylor and Francis, NY. Nalidixic Acid (Systematic) [Internet]. Medline Plus Health Information, US National Library of Medicine, National Institutes of Health; [updated 1999 Jun 14; cited 2003 Mar 6]. Available from: http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202387.html Voyles, B. A. 2003. Personal communication. Antimicrobial Susceptibility Testing.