By
C. A. Bechdel
Abstract
The problem investigated was Serratia marcescens. We hypothesized that both Tetracycline and chloramphenicol will be effective against treating S. marcescens. The experiment was conducted with a single control group and two experimental groups. The experiment was replicated 8 times. The experiment showed that in testing the control group S. marcescens, chloramphenicol had a mean death zone of 30.9 mm +/- 2.80 mm, and tetracycline had a mean death zone of 20.8 mm +/- 2.91 mm. Chloramphenicol had a significantly greater mean death zone then that of tetracycline.
Introduction
The problem that was investigated in our experiment was to see which antibiotic was more effective in treating infections caused by S. marcescens. The results of this experiment are important because it shows us the susceptibility of this bacterium to both tetracycline and chloramphenicol under a controlled environment. S. marcesens is species of gram-negative bacteria. It is rod-shape like and comes from the family Enterobacteraceae. It is usually involved in nosocomial infections, particularly catheter-associated bacteremia, urinary track infections, and wound infections. It is responsible for 1.4% of nosocomial bacteremia cases in the United States. It is commonly found in the respitory and urinary tracks of hospitalized adults and in the gastrointestinal system of children. S. marcescens is a motile organism and can grow in temperatures ranging from 5–40°C and in pH levels ranging from 5 to 9. (Wikipedia 2011)
The first antibiotic tested against S. marcescens was chloramphenicol. Chloramphenicol is a bacteriostatic antimicrobial. It is considered a prototypical broad-spectrum antibiotic that acts by disrupting protein synthesis. Chloramphenicol is effective against a wide variety of Gram-positive and Gram-negative bacteria, including most anaerobic organisms. (Prentice Hall Nurse’s Drug Guide