Antibiotic Sensitivity Profiles of Culturable Freshwater Bacteria
Location
CSU
Student's Major
Biological Sciences
Student's College
Science, Engineering and Technology
Mentor's Name
Elaine O. Hardwick
Mentor's Department
Biological Sciences
Mentor's College
Science, Engineering and Technology
Description
Bacteria were isolated and cultured from Hiniker Pond and Ox Bow Lake, recreational areas found within the city limits of Mankato, MN. Using the Kirby-Bauer Antibiotic Disk-Diffusion Method, the isolates were tested for sensitivity to six antibiotics (amoxicillin, chloramphenicol, erythromycin, penicillin, tetracycline and streptomycin). A Mueller-Hinton agar plate was covered completely with an isolate, specific antibiotic disks were placed, and plates were then incubated at room temperature for 24 - 48 hours. The degree to which bacteria were able to withstand and grow in the presence of antibiotics was measured as zones of inhibition. The recorded zones were compared to a known standard to categorize a bacterial isolate as resistant, intermediate or sensitive to each type of antibiotic. Of the 106 isolates, 31 percent were found to be resistant to at least one of the antibiotics tested, and 17 percent of these displayed multiple resistance (i.e., were resistant to at least two or more antibiotics). Most isolates were resistant to penicillin (31 percent) and streptomycin had the lowest resistance (4 percent). Freshwater phenol-degrading bacteria were also assayed for antibiotic sensitivity. For these isolates, 45 percent were resistant to at least one antibiotic and 26 percent displayed multiple antibiotic resistance.
Antibiotic Sensitivity Profiles of Culturable Freshwater Bacteria
CSU
Bacteria were isolated and cultured from Hiniker Pond and Ox Bow Lake, recreational areas found within the city limits of Mankato, MN. Using the Kirby-Bauer Antibiotic Disk-Diffusion Method, the isolates were tested for sensitivity to six antibiotics (amoxicillin, chloramphenicol, erythromycin, penicillin, tetracycline and streptomycin). A Mueller-Hinton agar plate was covered completely with an isolate, specific antibiotic disks were placed, and plates were then incubated at room temperature for 24 - 48 hours. The degree to which bacteria were able to withstand and grow in the presence of antibiotics was measured as zones of inhibition. The recorded zones were compared to a known standard to categorize a bacterial isolate as resistant, intermediate or sensitive to each type of antibiotic. Of the 106 isolates, 31 percent were found to be resistant to at least one of the antibiotics tested, and 17 percent of these displayed multiple resistance (i.e., were resistant to at least two or more antibiotics). Most isolates were resistant to penicillin (31 percent) and streptomycin had the lowest resistance (4 percent). Freshwater phenol-degrading bacteria were also assayed for antibiotic sensitivity. For these isolates, 45 percent were resistant to at least one antibiotic and 26 percent displayed multiple antibiotic resistance.
