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Journal of Clinical Microbiology, September 2001, p. 3386-3389, Vol. 39, No. 9
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.8.3386-3389.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
First Report of Human Infection Due to the Fungus
Triadelphia pulvinata
Saleh S. A.
Al-Hedaithy*
The Medical Mycology Unit, Department of
Pathology and Microbiology, College of Medicine and King Khalid
University Hospital, Riyadh 11461, Saudi Arabia
Received 27 October 2000/Returned for modification 29 March
2001/Accepted 14 May 2001
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ABSTRACT |
Triadelphia pulvinata, a soil hyphomycete, was found to
be the cause of eczematoid, scaly, grey lesions on the skin of both eyelids of a 30-year-old Indian male living in Saudi Arabia. Repeated KOH preparations of the skin scrapings showed presence of sclerotic, branched, septate hyphae. When cultured, skin scrapings from the lesion
grew the dematiaceous fungus T. pulvinata. Treatment with topical clotrimazole cured the infection, and no recurrence of the
infection was noted in a 5-year follow-up.
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TEXT |
Triadelphia pulvinata is
a rather rare dematiaceous hyphomycete. It was described as new in 1978 by Maggi et al. (4) following its isolation for the first
time from the rhizosphere of the grass Loudetia simplex in
the Ivory Coast. The second isolation of the mold was achieved
coincidentally by the author in 1981 from soils collected in Saudi
Arabia that were contaminated with bat guano. This occurred during a
countrywide search in Saudi Arabia for the pathogen Histoplasma
capsulatum using a method employing mouse inoculation with soil
suspensions from suspicious sites (1). Further studies
with experimental mice led to findings and the reporting of T. pulvinata as a potential human pathogen (2). This
paper reports the first human infection by T. pulvinata.
(An abstract of this paper was presented as a poster in the Fourteenth
Congress of the International Society for Human and Animal Mycology
held from 8 to 12 May 2000 in Buenos Aires, Argentina.)
Case report.
The infection involved a 30-year-old Indian male
who worked as a porter in one of the hospitals in Riyadh. He made
round-trip visits to his country of origin during his annual vacations.
The patient presented with itchy, grey, scaly, eczematoid lesions of 6 months' duration on the skin of both eyelids (Fig. 1). He was seen previously by
dermatologists on three different occasions and was put on topical
corticosteroids each time. These relieved the itching and quieted the
lesions; however, when the treatment course was completed, the
symptoms recurred. The patient was healthy otherwise, and the routine
chemical and hematological laboratory investigations were within
normal limits. Also, his chest X-ray was normal. Skin scrapings from
each of the two lesions were collected. Portions of the scrapings were
used for direct microscopic examination in 10% KOH and for culture on
Sabouraud dextrose agar (SDA) and on SDA supplemented with 50 µg of
chloramphenicol ml
1 (Oxoid Ltd., Basingstoke, England),
which were incubated at 26 (±1)°C. The direct microscopic
examination of the skin scrapings revealed the presence of branched
hyphae (Fig. 2A), and the cultures grew
an unusual dematiaceous mold which was identified as T. pulvinata (Fig. 2B and 3). Since the organism was very uncommon,
repeat skin scrapings from both lesions were taken and their analysis resulted in the same findings by direct microscopy and culture. Therefore, the patient was treated with topical clotrimazole cream (canesten cream containing 0.01 g of clotrimazole/g of cream; Bayer, Leverkusen, Germany) applied to each of the lesions twice daily for 4 weeks. The lesions resolved considerably after the 2nd
week, and a full cure was achieved after the 4th week. No relapse of
the infection was observed during a 5-year follow-up.
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FIG. 2.
(A) Branched hyphae of T. pulvinata in
scrapings of eyelid skin lesions (10% KOH preparation). (B)
Two-week-old colony of T. pulvinata on SDA incubated at
26 (±1)°C.
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For identification studies, the isolated fungus was subcultured onto
fresh SDA and cornmeal agar media and was incubated at
26 (±1) and
37°C. It grew well on both media and at both temperatures,
with
moderate growth rates. During the first 3 or 4 days, the
colonies
appeared creamy and moist. During the next 2 weeks, the
centers turned
brown and then grey-black as the organism matured
(Fig.
2B). Hyphae
were hyaline and thin. Some collected in fascicles
or coils on which
aggregates of hyaline to light-brown, pyriform,
sporogenous cells were
formed. The fungus produced three forms
of conidia: (i)
brown, oval, unicellular conidia; (ii) brown,
cylindrical, one-septate
conidia; and (iii) hyaline, acicular
conidia with 5 or 6 septates
tapering to a long break (Fig.
3).
It is because of
these features that the fungus was identified
as
T. pulvinata (
3,
4). The isolates were preserved in our
culture collection under the numbers 4289 and 4989.
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FIG. 3.
Lactophenol cotton blue mounts of 2-week-old cornmeal
agar slide cultures of T. pulvinata incubated at 26 (±1)°C. (A) The three forms of conidia produced by the fungus are
(i) brown, oval, and unicellular (upper middle area); (ii) brown,
cylindrical, and one-septate (lower middle area); and (iii) hyaline and
acicular, with five or six septates (center area). (B) Brown,
unicellular conidia. (C) Brown, one-septate conidia.
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Examination of the literature did not reveal any previous report of a
human infection caused by this fungus. In fact, not
only has organism
not been implicated in any infection, the published
reports on
T. pulvinata itself are very limited. It is not familiar
to many
mycologists. It sporulates readily, but its identification
may not be
straightforward because of its pleomorphic nature.
All species of the
genus
Triadelphia are pleomorphic, producing
at least
two forms of conidia from sporogenous cells that agglomerate
in a
sporodochium-like aggregate (
3,
5). No difficulty was
encountered in identifying the present isolates because of previous
experience with the fungus (
2).
It is not clear how the patient acquired his infection. He denied
having visited a particular bat site in Saudi Arabia or
India, but
he occasionally went to farms or moist ecosystem grasses.
The case reported herein represents the first human infection
caused by
T. pulvinata.
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ACKNOWLEDGMENTS |
The contribution to this case by Ibrahim Al-Rabieh from our
Dermatology Department is acknowledged.
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FOOTNOTES |
*
Mailing address: The Medical Mycology Unit,
Department of Pathology and Microbiology, College of Medicine and King
Khalid University Hospital, P.O. Box 2925, Riyadh 11461, Saudi Arabia. Phone: 9661-467-1010. Fax: 9661-467-2366. E-mail:
hedaithy{at}ksu.edu.sa.
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REFERENCES |
| 1.
|
Al-Hedaithy, S. S. A., and C. R. Leathers.
1987.
Country-wide search in Saudi Arabia for the etiologic agent of histoplasmosis.
Proc. Saudi Biol. Soc.
10:197-207.
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| 2.
|
Al-Hedaithy, S. S. A., and C. R. Leathers.
1987.
Presence of Triadelphia pulvinata in Saudi Arabia and its potential pathogenicity.
Proc. Saudi Biol. Soc.
10:209-216.
|
| 3.
|
Constantinescu, O., and R. A. Samson.
1982.
Triadelphia, a pleomorphic genus of Hyphomycetes.
Mycotaxon
15:472-486.
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| 4.
|
Maggi, O.,
A. Bartoli, and A. Rumbelli.
1978.
Two new species of Triadelphia from rhizosphere of Loudetia simplex in the Ivory Coast.
Trans. Br. Mycol. Soc.
71:148-154.
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| 5.
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Shearer, C. A., and J. L. Crane.
1971.
Fungi of the Chesapeake Bay and its tributaries. I. Patuxent River.
Mycologia
63:237-260.
|
Journal of Clinical Microbiology, September 2001, p. 3386-3389, Vol. 39, No. 9
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.8.3386-3389.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
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