Date of Award


Document Type



Environmental and Forest Biology

Thesis Advisor

Christopher Whipps


The zebrafish, Danio rerio, is an important model organism in the field of biomedical research. Unfortunately, these fish are negatively impacted by different species of Mycobacterium which cause subclinical infections, lesions on the body, and sometimes premature death. When new fish are introduced to a facility, it is typically by eggs only, and the standard disinfection practice, a treatment of 50ppm sodium hypochlorite, has unknown efficacy for killing mycobacteria. This study tested 100ppm and 150ppm bleach, as well as 1.5% and 3% hydrogen peroxide and 100ppm iodine, to determine the germicidal efficacy for use in fish facilities. Cultures of M. gordonae and M. peregrinum grown in Middlebrook broth were used. Each trial included a positive control, low concentration, and high concentration of disinfectants; iodine contained only a control and low treatment. Bleach was applied for 10 minutes and deactivated by sodium thiosulfate while hydrogen peroxide and iodine were applied for 5 minutes and removed. Plate counts were made on treatment and control groups following serial dilution and a week of growth at 30 degree C. Only iodine resulted in complete killing of both Mycobacterium species tested. Bleach treatment impacted growth of both species. The hydrogen peroxide only impacted M. peregrinum. ANOVA statistical analysis showed the following significant differences: 1) bleach treated cultures of M. peregrinum exhibited less growth than untreated.

Included in

Bacteria Commons