Submitted to: Interscience Conference on Antimicrobial Agents & Chemotherapy Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 29, 2006
Publication Date: September 27, 2006
Citation: De Lucca II, A.J. 2006. In vitro inhibitory and fungicidal properties of EDTA for Aspergillus and Fusarium. in: Proceedings of Interscience Conference on Antimicrobial Agents & Chemotherapy, September 27-30, 2006, San Francisco, CA. Abstract M-1780. p. 439.
Background: Ethylenediaminetetra-acetic acid (EDTA) is approved for food preservation, treatment for hypercalcemia and heavy metal poisoning and as a blood count tube anticoagulant. Reports indicate EDTA also 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 30 degrees C. Conidia (2.5X10**4/ml) were prepared in 1% potato dextrose broth (PDB), pH 4.86. Lethality assays: Three separate runs were performed (n=12). Aliquots (25 ul) of nongerminated and germinating conidia (0 and 8 hr incubation, respectively) were added to EDTA (final concentrations: 0-1600 ug/ml). Final volume was 250 ul. After 30 min incubation (37 degrees C) Aliquots (50 ul) were spread on each of 4 potato dextrose agar plates/dilution. Plates were incubated for 48 hr at 30 degrees C and colonies enumerated. Sigma Stat 9.0 was used for statistical analyses. Inhibition studies: Three separate runs were performed with triplicate wells/EDTA dilution (n=9). Conidia were diluted to 2X10**4/ml in PDB. Aliquots (25 ul) of conidia were added to microplate wells having increasing concentrations of EDTA (final concentrations: 0-1600 ug/ml) with final volumes of 250 ul. Microwell plates were incubated at 37 degrees C. Inhibition was visually determined at 48 hr with a 4-power magnifying loop and defined as no visable growth. Results: EDTA inhibited the nongerminating conidial growth of: A. flavus (100 ug/ml), A. fumigatus (12.5 ug/ml), A. niger (400 ug/ml), F. moniliforme (25 ug/ml), F. solani (400 ug/ml); germinating conidia: A. flavus (less than 1600 ug/ml), A. fumigatus (6.25 ug/ml), A. niger (200 ug/ml), F. moniliforme (25 ug/ml), F. solani (400 ug/ml). EDTA was not significantly lethal for the tested conidia. Conclusions: Under test conditions, EDTA is not fungicidal but inhibits hyphal development of dormant and germinating conidia.