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Penicilliosis is caused by
Penicillium marneffei, a ubiquitous saprophyte of soil and decomposing
organic matter.
A disseminated
and progressive infection, penicilliosis marneffei is the third most
common opportunistic infection in human immunodeficiency virus
(HIV)-infected patients in certain parts of Southeast Asia.
Penicillium marneffei is endemic in Southeast Asia
and
Far East Asia, particularly in the southern
part of China. Cases have been reported from both Eastern and Western
countries.
Of the more than 150 recognized species
of Penicillium, only P. marneffei is known to be dimorphic and to
cause invasive infection.
Prior to the
epidemic of human immunodeficiency virus (HIV), penicilliosis was a
rare event. The incidence of this fungal infection has increased
markedly during the past few years, paralleling the incidence of HIV
infection.
Mode of infection: Most
human infections probably have a pulmonary inception after inhalation
of airborne infectious conidia of P. marneffei produced in the
environment.
Persons who are debilitated or
immunocompromised appear to be at increased risk of infection.
Clinical
presentation:
Patients with disseminated
penicilliosis marneffei often present with chronic productive cough,
mucoid sputum, chest pain, generalized lymphadenopathy ,
hepatosplenomegaly , draining skin ulcers, subcutaneous abscesses ,
osteolytic lesions , anemia , leukocytosis ,and a history of weight
loss and prolonged intermittent fever.
The skin lesions are most commonly papules with central necrotic umbilication.
Course of
the disease :
The course of the disease can range from 2 months to 3 years or more.
Organs
involved:
Organs most frequently involved include the lungs, liver,
intestine, lymph nodes, tonsils, skin, bone marrow, kidneys, and
spleen.
Pathological Features:
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Image6 . (Dr Tsutsumi)
The host response in penicilliosis
marneffei is similar to that seen in histoplasmosis , where numerous
small yeast-like cells proliferate within and distend histiocytes.
Visit:
Histoplasmosis
Slowly evolving pulmonary abscesses and
granulomas can lead to fibrosis and cavitation, but calcification has
not been reported.
In histologic sections, the cells
of P. marneffei are spherical to oval, 2.5 to 5 micrometer in
diameter, and resemble those of Histoplasma capsulatum.
However, unlike histoplasma and other
invasive yeast-like fungi, P. marneffei does not bud.
Reproduction is by fission (schizogony)
with the formation of a single transverse septum that stains more
intensely with the special stains for fungi and is wider than the
external wall.
Short hyphal forms and elongated,
curved sausage-like forms with rounded ends and one or more septa are
also occasionally produced, especially in the necrotic and cavitary
lesions.
Diagnosis:
A definitive diagnosis of penicilliosis
marneffei can be made by demonstration of typical yeast-like cells in
clinical specimens and by microbiologic culture an standard mycologic
media.
Treatment:
The mycosis must be aggressively
treated with amphotericin B, 5-fluorocytosine, or keratoconazole.
Because relapse is common, antifungals
should be given for several months.
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