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SENSITIVITY OF THREE ENCEPHALITOZOON SPECIES TO CHLORINE AND CHLORAMINE TREATMENT AS DETECTED BY AN IN-VITRO MICROWELL PLATE ASSAY (POSTER PRESENTATION)
Citation:
Johnson*, C H., M. M. Marshall, J. Moffett, C. R. Sterling, L DeMaria*, AND E W. Rice*. SENSITIVITY OF THREE ENCEPHALITOZOON SPECIES TO CHLORINE AND CHLORAMINE TREATMENT AS DETECTED BY AN IN-VITRO MICROWELL PLATE ASSAY (POSTER PRESENTATION). Presented at 101st Meeting of ASM, Orlando, FL, 5/22-24/2001.
Description:
Microsporidia are obligate intracellular parasites that form environmentally resistant, infectious spores. These parasites are ubiquitous in the environment, infecting members of almost every class of verebrates and invertebrates. At least 14 microsporidian species that infect the human gastrointestinal tract, Enterocytozoon bieneusi and Encephalitozoon intestinalis. Spores are typically able to survive and maintain their infectivity for weeks. A modified in-sitro cell culture assay was performed on three species of Encephalitozoon after exposure to chlorine and chloramine at a concentration of 2 mg/liter at25C, pH 7 and pH8, respectively. Spores were harvested from RK-13 cell monolayers, Percoll purified, and assayed assayed using an in-vitro microwell plate viability procedure. Ten fold dilutions of chlorine and chloramine treated spores were inoculated onto RK-13 cell monolayers grown on 15mm sterile Thermanox coverslips in 24 well plates. Five coverslips were inoculated for each spore dilution. After incubation, the coverslips were fixed with methanol, stained with Giemsa stain, and examined with a light microscope. The percentage of infectivity was calculated by dividing the number of positive (infected) wells by the total number of wells inoculated. MPN determinations were also determined for each assay. For each treatment and time period, two replicates of 5 coverslips were performed. Varying log reductions were observed for the three Encephalitozoon species.