In the strain sample (Table 1),
all 66 isolates came from microscopy-positive specimens, as
mentioned above. In the nail sample, fungal filaments were
seen in the KOH preparations in 181 out of 195 specimens
(93%), while a culture of a potential agent of onychomycosis
grew from 44 specimens (22%; Table 2). T. rubrum made up
83% of isolates from the strain sample and 95% of isolates
from the nail sample; when both samples were combined, it
made up 88% of isolates. The remaining cultures were mainly
T. interdigitale, with S. brevicaulis also being identified on two
occasions. Of the two S. brevicaulis isolates found in the nail
sample, each was confirmed a posteriori as etiologic by means
of later studies on repeat specimens, and one was obtained
from a specimen also yielding T. rubrum.