Antibiotic Responsiveness in Mycobacterium smegmatis

Date of Award


Document Type




First Reader

Dr. Ruth Plymale


Antibiotic resistance is an area of growing concern in the medical field. Previously treatable illnesses are now not responsive to some antibiotics. This growing resistance problem leads us to a search for antibiotics that could offer new treatment options. Tuberculosis, though not a common problem in the United States, is one of the more serious illnesses among the antibiotic resistance spectrum. Antibiotic resistant strains of pathogens are generally caused by the misuse of therapeutic antibiotics. Once these resistant antibiotic strains are present in a population, they are more likely to spread and infect others. In areas where proper treatment is not available for tuberculosis, antibiotic resistant strains begin to grow out of control.

Throughout this project, we are looking for alternative antibiotics that could potentially be used to control Mycobacterium tuberculosis, the bacterium that causes tuberculosis. However, because of the risks associated with using M. tuberculosis in the lab, Mycobacterium smegmatis mc2155 was used as a surrogate. M. smegmatis is similar in cell structure and size to M. tuberculosis, leading us to believe the results of the antibiotics on M. smegmatis would be comparable to those on M. tuberculosis.

Antibiotics were produced from different soil bacteria grown in either peptone starved or glucose starved media, and the antibiotics were extracted using an acetonitrile:water:acetic acid solvent. The extracted antibiotics were tested against M. smegmatis to determine their success at inhibiting cellular respiration. The effectiveness of the lab-produced antibiotics was determined using 2,3,5-triphenylatetrazolium chloride (TTC) and was compared to that of isoniazid, a commercial antibiotic commonly used in tuberculosis treatment. The results of these cellular respiration assays will be presented.

This document is currently not available here.