Research and Development - Indoor Air Quality
Title: Enhanced Recovery of Stachybotris chartarum
from Environmental Samples
Authors: R. A. Billups, K. S. Tilton, Ph.D., and
P. S. Warden
ABSTRACT:
Recovery of Stachybotrys chartarum (atra) from environmental
samples can be difficult due to competition from other more aggressive
fungi even on selective media such as Cellulose Agar. S. chartarum
ATCC 9182, ATCC 34915, along with Stachybotrys spp. isolated
from environmental samples and common competing fungi (Aspergillus
flavus, A. niger, Cladosporium brevitomosum,
and Penicillium chrysogenum) were grown as mixed cultures
in the laboratory under experimental conditions to optimize the
procedures used for Stachybotrys spp. recovery. Potato
Dextrose Agar (PDA) was chosen as the experimental media based on
previous studies at Analytical Services, Inc. which demonstrated
that PDA allowed more rapid expression of diagnostic Stachybotrys
morphology than Cellulose Agar, Corn Meal Agar, and Malt Extract
Agar. Trials were completed using Amphotericin B, Cycloheximide,
Miconazole, and Chloramphenicol added at various concentrations
to PDA to suppress fungal and bacterial competition. Cultures were
incubated at 22°C and 35°C for up to twelve (12) days. Miconazole
was most effective at inhibiting growth of the selected non-target
fungi while allowing Stachybotrys growth. Characteristic,
recognizable S. chartarum colonies were observed at both temperatures,
but development was notably faster at 22°C. None of the competitive
fungi grew at either temperature on the specialized agar; however,
only a limited number of fungal types were tested. The combination
antibiotic/antimycotic modified PDA and incubation at 35°C appears
to effectively reduce competition and allow enhanced recovery of
Stachybotrys spp.
Presented at the can Industrial Hygiene Conference & Exposition
(AIHCE), June 1999, Toronto,ON |
