Journal of Veterinary Diagnostic Investigation
2016, Vol. 28(3) 350 –353
© 2016 The Author(s)
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Trichosporon is a genus of yeast-like anamorphic fungi with
distinct morphological features of true mycelium that forms
arthroconidia.15 These organisms are not considered primary
pathogens and are widely distributed in the environment, nor-
mally inhabiting the cutaneous, oral, gastrointestinal, respira-
tory, and reproductive tract of humans and other animals.7,19
To date, there are 50 reported species of Trichosporon classi-
fied within different clades; only 15 species are of potential
medical interest.7 Infection and clinical disease in humans is
typically superficial and mild in immunocompetent individu-
als, but systemic and fatal in immunocompromised patients.7
In addition, allergic pneumonia has been attributed to inhala-
tion of Trichosporon arthroconidia from the environment dur-
ing the summer in Japan.2 In veterinary medicine, multiple
species of Trichosporon have been associated with clinical
disease, including dermatitis, rhinitis, and cystitis in cats,9,12,17
meningoencephalitis in dogs,5 mastitis in cattle,8,11 and der-
matitis in horses and nonhuman primates.14
Our study describes a case of systemic T. loubieri infec-
tion in an 8-year-old Domestic Longhair cat that was pre-
sented to a private clinic because of acute dyspnea, anorexia,
and aggressiveness. No history of Feline immunodeficiency
virus and Feline leukemia virus infection was available, but
the cat had never been vaccinated. Thoracic radiographs
and ultrasound revealed a possible diaphragmatic hernia
and diffuse pleural effusion, respectively. The cat was
placed under general anesthesia and subjected to a brief
exploratory laparotomy. No diaphragmatic hernia was
detected, but 2 ulcerative lesions were noted in the abdomi-
nal skin during surgery. Thoracic fluid was removed by tho-
racocentesis, and additional radiographs revealed multiple
thoracic nodules, suggesting a possible lymphoma or gran-
ulomatous disease. The cat was discharged after recovery
from anesthesia and prescribed cefovecin, buprenorphine,
and furosemide, but re-presented a week later with severe
dyspnea. Cytological examination of impression smears
obtained from the thoracic effusion after a new thoracocen-
tesis revealed scattered neutrophils and macrophages. Mul-
tiple other ulcerative lesions were also observed over the
left aspect of the neck, right and left thorax, and abdomen
(Fig. 1). Dyspnea persisted for an additional week, and
other cutaneous lesions were found. Multiple punch biop-
sies and a swab sample were taken from the cutaneous
lesions for histologic examination and culture, respectively.
Biopsy samples were received immersed in 10% neutral
buffered formalin, and were routinely processed for histology
640313VDIXXX10.1177/1040638716640313Trichosporon loubieri infection in a catRissi, Kirby, Sanchez
Department of Pathology and Athens Veterinary Diagnostic
Laboratory, College of Veterinary Medicine, The University of Georgia,
Athens, GA (Rissi); LaGrange Veterinary Hospital, LaGrange, GA
(Kirby); and Department of Infectious Diseases and Athens Veterinary
Diagnostic Laboratory, College of Veterinary Medicine, The University of
Georgia, Athens, GA (Sanchez).
1Corresponding Author: Daniel R. Rissi, Department of Pathology,
College of Veterinary Medicine, The University of Georgia, Athens, GA
Systemic Trichosporon loubieri infection
in a cat
Daniel R. Rissi,1 Kerry D. Kirby, Susan Sanchez
Abstract. Our study describes a case of systemic Trichosporon loubieri infection in a cat with acute dyspnea, anorexia,
and aggressiveness. Physical examination revealed multiple ulcerative cutaneous lesions on the abdomen, neck, and thorax.
Thoracic radiographs and ultrasound showed multiple mediastinal nodules and marked pleural effusion, respectively. A
cutaneous biopsy from the ulcerated wounds revealed necrogranulomatous dermatitis and panniculitis with numerous
intralesional fungal hyphae. Fungal culture on fresh swab samples from the cutaneous lesions yielded growth of a fungal
organism that was further identified as Trichosporon loubieri by PCR and DNA sequencing. The cat was subsequently
euthanized and submitted to autopsy. Gross pathology changes consisted of multifocal to coalescing white nodules ranging
from 5 to 10 mm in diameter that expanded the mediastinal fat, intrathoracic lymph nodes, lungs, and costal pleura. These
lesions consisted of areas of necrogranulomatous inflammation with numerous intralesional fungal hyphae morphologically
similar to those observed in the cutaneous biopsy sample. Gross and histologic changes were consistent with a systemic fungal
infection, and the etiologic diagnosis was supported by fungal culture. Fungal identity was confirmed by DNA sequencing
of D1-D2 and TS1 regions.
Key words: Cats; dermatitis; panniculitis; systemic infection; Trichosporon loubieri.
Trichosporon loubieri infection in a cat 351
and stained with hematoxylin and eosin (HE). Histologic
changes consisted of necrogranulomatous dermatitis and
panniculitis with numerous intralesional fungal hyphae
(Fig. 2). The dermis and subcutaneous tissue were multi-
focally effaced by extensive areas of necrosis containing
fibrin and cell debris or clusters of foamy and epithelioid
macrophages admixed with neutrophils and numerous
free and intrahistiocytic organisms morphologically con-
sistent with fungal hyphae. The inflammation occasion-
ally extended into the underlying skeletal muscle.
Adjacent periadnexal areas had mild lymphoplasmacytic
inflammation, and the overlying epidermis had areas of
ulceration and suppurative inflammation or hyperplasia
with orthokeratotic hyperkeratosis. Replicate sections
stained with Grocott methenamine silver special stain
(GMS; Fig. 3) and periodic acid–Schiff (PAS; Fig. 4)
reaction revealed myriads of 4–6 um wide, septate fungal
hyphae with non-parallel walls, nondichotomous branch-
ing, and terminal bulbous dilations. Swab culture yielded
heavy growth of a nonpigmented fungus with arthroco-
nidia on all media, but identification based on morphol-
ogy was not possible. PCR and DNA sequencing of the
D1-D2 and TS1 regions revealed a 100% similarity of the
organism to Trichosporon loubieri (GenBank accession
Because of the likelihood of a systemic fungal infection
and poor prognosis, the cat was subjected to euthanasia and
autopsy. Gross pathology changes consisted of multifocal to
coalescing white nodules ranging from 5 to 10 mm in diam-
eter that expanded the mediastinal fat, intrathoracic lymph
nodes, lungs, and costal pleura (Fig. 5). No other gross ana-
tomic changes were observed. Fragments of multiple tissues
were fixed in 10% neutral buffered formalin, routinely pro-
cessed for histology, and stained with HE. Histologic
Figure 1. Three ulcerative lesions with hemorrhage in the
Figure 2. Punch biopsy from the cutaneous lesions reveals dense
pyogranulomatous inflammation in the dermis with intralesional
fungal hyphae (arrowhead). Hematoxylin and eosin. Bar = 50 µm.
Figure 3. Fungal organisms are highlighted by Grocott
methenamine silver special stain. Hyphae are 4–6 um wide; septate
fungal hyphae with nonparallel walls, nondichotomous branching,
and terminal bulbous dilations. Grocott methenamine silver stain.
Bar = 50 µm.
Figure 4. Same section shown in Figure 3 stained with periodic
acid–Schiff reaction. Bar = 50 µm.
Rissi, Kirby, Sanchez
examination of multiple samples revealed disseminated,
fairly nodular areas of necrogranulomatous inflammation
with numerous intralesional fungal hyphae throughout the
costal and visceral pleura, lungs, mediastinal fat, and tho-
racic lymph nodes (Fig. 6).
Our report documents a case of systemic infection by T.
loubieri in a cat, a fungal organism that has been associated
with rhinitis but no systemic infection in this species to
date.18 Infection was characterized by ulcerative and pyo-
granulomatous dermatitis and panniculitis, pleuritis, pneu-
monia, and thoracic lymphadenitis. Intralesional GMS- and
PAS-positive fungal organisms were abundant in all exam-
ined tissues and were morphologically consistent with what
has been described for this fungal organism.5,9,12 The etio-
logic diagnosis was supported by fungal culture on swab
samples from the cutaneous lesions, and fungal identity was
achieved by PCR with subsequent DNA sequence analysis.
These tests are typically required for a definitive diagnosis
because identification of these fungal organisms by conven-
tional methods, such as biochemical profile and morphology,
is often difficult and frequently inconclusive.3,6,18
Systemic fungal infections in cats are typically divided
into those caused by opportunistic agents, such as Crypto-
coccus neoformans, and those where the organisms are able
to infect an immunocompetent host. The latter usually takes
place via inhalation of conidia and include Blastomyces der-
matitidis, Coccidioides immitis, and Histoplasma capsula-
tum infection.13 Trichosporon is an ubiquitous organism and
is not considered a primary pathogen.6 Organisms are widely
distributed in nature, and although most species are associ-
ated with superficial cutaneous infection in immunocompe-
tent humans, opportunistic infections causing systemic
disease may affect immunocompromised and/or hospitalized
patients worldwide.7 Although superficial infection (referred
to as white piedra) is mild and restricted to the hair shafts in
the scalp, face, axilla, and genitalia,7 systemic disease is fre-
quently fatal and is characterized by arthritis, endocarditis,
peritonitis, esophagitis, meningitis, cerebral, splenic and
hepatic abscesses, and urinary tract infection.7 Infection by
Trichosporon spp. has been rarely documented in the veteri-
nary medical literature. Most cases have been reported in
cats and consist of nasal granulomas associated with T. pul-
lulans and T. loubieri infection,12,18 suppurative and hemor-
rhagic cystitis as a result of T. beigelii and T. domesticum
infection,9,17 and ulcerative dermatitis caused by infection by
an unclassified Trichosporon sp.9 Although systemic infec-
tion in cats may also be associated with chronic debilitating
disease, such as lymphoma or diabetes mellitus, no clinical
or pathological evidence of any other underlying disease was
detected in the cat of the current report.9 Cutaneous lesions in
cats infected with B. dermatitidis, C. immitis, and H. capsu-
latum typically reflect an underlying systemic infection that
occurs primarily by inhalation of the organisms.13 Therefore,
based on the pathological changes in the present case, it is
plausible that the respiratory infection may have preceded
the cutaneous lesions. Other animal species have also been
reported as susceptible to infection by Trichosporon. T. mon-
tevideense has been associated with granulomatous menin-
goencephalitis in dogs,5 and T. cutaneum has been implicated
as the cause of otitis externa or dermatitis and nasal granulo-
mas in dogs.4,10 In addition, T. beigelii has been associated
with outbreaks of mastitis in dairy cattle,8,11 and T. montevi-
deense was isolated from a case of onychomycosis in a Japa-
nese monkey.1 Although the zoonotic potential of
Trichosporon has not been confirmed, transmission from
affected animals to humans should be considered in case
infection is suspected. Treatment appears to be ineffective in
the majority of Trichosporon infections in humans and other
animals, mainly because these organisms show species-
related resistance to a variety of antifungal drugs.3 Therefore,
early diagnosis of fungal infection and speciation of clinical
samples is recommended to distinguish highly pathogenic
Figure 5. Multifocal to coalescing white nodules expand the
mediastinal fat, intrathoracic lymph nodes, lungs, and costal pleura.
Figure 6. A pulmonary granuloma expanding and compressing
the parenchyma (right) and forming pleural nodules (arrowhead).
Hematoxylin and eosin. Bar = 500 µm.
Trichosporon loubieri infection in a cat 353
from less pathogenic strains and to promptly determine a
susceptibility drug profile.3,16,18
We thank Amy S. McKinney, Ashely E. Phillips, and Ingrid Fernandez
for their technical assistance with fungal culture and PCR.
DR Rissi contributed to conception and design of the study; contributed
to acquisition, analysis, and interpretation of data; and drafted the man-
uscript. KD Kirby contributed to design of the study, and contributed to
acquisition of data. S Sanchez contributed to conception and design of
the study, and contributed to acquisition, analysis, and interpretation of
data. All authors critically revised the manuscript; gave final approval;
and agreed to be accountable for all aspects of the work in ensuring that
questions relating to the accuracy or integrity of any part of the work
are appropriately investigated and resolved.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect
to the research, authorship, and/or publication of this article.
The author(s) received no financial support for the research, author-
ship, and/or publication of this article.
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