Background: Ethylenediaminetetra-acetic acid (EDTA) is approved for food preservation, treatment for hypercalcemia and heavy metal poisoning. Reports indicate EDTA inhibits microbial growth. This study investigated EDTA lethality and inhibitory properties for Aspergillus and Fusarium species that are plant and human pathogens. Methods: Aspergillus flavus, A. fumigatus, A. niger, Fusarium moniliforme and F. solani conidia were harvested from 7 day-old slant cultures grown at 30Â°C. Conidia (2.5X104/ml) were prepared in 1% potato dextrose broth (PDB), pH 4.8. Lethality assays: Three separate runs were performed (n=12). Aliquots (25 μl) of nongerminated and germinating conidia (0 and 8 hr incubation, respectively) were added to EDTA (final concentrations: 0-1600 μg/ml). Final volume was 250 μl. After 30 min incubation (37Â°C) Aliquots (50 μl) were spread on each of 4 potato dextrose agar plates/dilution. Plates were incubated for 48 hr at 30Â°C and colonies enumerated. Sigma Stat 9.0 was used for statistical analyses. Inhibition studies: Three separate runs were performed with triplicate wells per EDTA dilution (n=9). Conidia were diluted to 2X104/ml in PDB. Aliquots (25 μl) of conidia were added to microplate wells having increasing concentrations of EDTA (final concentrations: 0-1600 μg/ml) with final volumes of 250 μl. Microwell plates were incubated at 37Â°C. Inhibition was visually determined at 48 hr with a 4-power magnifying loop and defined as no visable growth. Results: EDTA inhibited at 48 hr the nongerminating conidial growth at concentrations of: A. flavus (100 μg/ml), A. fumigatus (12.5 μg/ml), A. niger (400 μg/ml), F. moniliforme (25 μg/ml), F. solani (400 μg/ml); germinating conidia: A. flavus (>1600 μg/ml), A. fumigatus (6.25 μg/ml), A. niger (200 μg/ml), F. moniliforme (25 μg/ml), F. solani (400 μg/ml). EDTA was not significantly lethal for the tested conidia. Conclusions: Under test conditions, EDTA is not fungicidal but inhibits hyphal development in nongerminated and germinating conidia.
Full conference title:
46th Interscience Conference on Antimicrobial Agents and Chemotherapy
- ICAAC 46th