Antimicrobial Activity of Soil Bound Antibiotics.
(S11-chander633887-poster)
Authors:
Y. Chander* - Univ. of Minnesota K. Kumar - Univ. of Minnesota S.C. Gupta - Univ. of Minnesota A.K. Singh - Univ. of Minnesota S.M. Goyal - Univ. of Minnesota
Abstract:
Antibiotics have a strong tendency to bind to clay particles in soil. However, it is not known if soil-bound antibiotics retain their antimicrobial activity or not. The objective of this study was to determine if soil-adsorbed antibiotics are metabolically active or do they lose their antibacterial
properties by interaction with soil particles. For this purpose, we prepared two soil types (Webster clay loam and Hubbard sandy loam) with various concentrations of adsorbed antibiotics and inoculated them with a tetracycline resistant strain of Salmonella, a tetracycline sensitive strain of Salmonella, or a tetracycline sensitive strain of E. coli (ATCC 25922). The soil-bacteria mixture was incubated for 24 hrs at 370C under both static and dynamic conditions followed by enumeration of bacterial growth.
Under both static and dynamic conditions, there was a decrease in the number of antibiotic sensitive strains but no appreciable decrease was noted in the numbers of antibiotic resistant Salmonella. These effects were more pronounced under dynamic mixing as compared to static mixing. These results indicate that antibiotics, when released in soil, may be bound with clay fraction of the soil but still maintain their antibacterial activity and may provide an environment for the selection of antibiotic resistant microorganisms in vitro.
Speaker Information: Yogesh Chander, Univ. of Minnesota, 1991 Upper Buford Circle Dept. of Soil, Water, &a, Saint Paul, MN 55108; Phone: 612 625 6787; E-mail: [email protected]
Session Information: Tuesday, November 4, 2003, 4:30 PM-6:00 PM Presentation Start: 4:30 PM (Poster Board Number: 1718)
Keywords: agricultural pharmaceuticals; tetracycline; microorganisms; antimicrobial activity
