Understanding Opportunistic Mycoses and Their Treatment

OPPORTUNISTIC MYCOSES
Dr. Dinesh Jain
Assistant Professor
Deptt. of Microbiology
SMS MC Jaipur

CLASSIFICATION ORGANISMS
Yeast Candida
Cryptococcus
Torulopsis
Trichosporon
Rhodotorula
Geotrichium
Molds Aspergillus
Pseudoallescheria
Zygomycetes (Rhizopus, Mucor, and Absidia
Monday, January 16, 2012

True Pathogenic Fungi Opportunistic Fungi
Diseases Histoplasmosis
Blastomycosis
Paracoccidioidomycosis
Coccidioidomycosis
Aspergillosis
Candidiasis
Mucormycosis
Cryptococcosis
Host Normal Abrogated/
Compromised
Portal of
Entry
Primary infection is
pulmonary
Various

True Pathogenic Fungi Opportunistic Fungi
Prognosis 99% spontaneous resolution Recovery depends on the
severity of impairment of
host defenses
Immunity Resolution results to strong
speciﬁc immunity
No speciﬁc resistance
infection
to
Host Response Tuberculoid granuloma,
mixed pyogenic
Depends on degree of
impairment necrosis to
pyogenic to
granulomatous
Morphology in
Tissue
All agents showed
dimorphism to a
form
tissue
No change in morphology
Distribution Geographically restricted Ubiquitous

CANDIDIASIS
C. albicans is the most common (4-6 um;
budding)
Multiplication: blastospore formation
producing either pseudohyphae or
septate hyphae
Identiﬁcation: assimilation and
fermentation of CHOs; physiologic and
morphologic responses they exhibit
when grown under controlled
nutritional conditions “germ tubes”

CANDIDIASIS
“chlamydoconidia”

FACTORS THAT AFFECT CANDIDA
NORMAL POPULATION
poor oral hygiene
use of antibiotics
use of oral contraceptives
diet
presence of antagonistic inhibitory bacteria

Candida albicans is a resident ﬂora of the
skin, mouth, vagina and stool!
Imbalance will lead to infection....HOW?
Changes in the Physiology: e.g.
pregnancy, use of steroids and diabetes
Prolonged administration of antibiotics
Immunocompromised patients

MUCOCUTANEOUS CANDIDIASIS
(MC)
a condition caused by a fungus from
the candida family (lives on the
surface of skin) that develops a
diffuse and persistent type of
infection of the mouth, nails, skin, and
at times other organs
affects infants (starts before age 3) and
young adults, is rarely seen in adults
with other diseases
including chronic mucocutaneous
candidaisis or CMCC

SYMPTOMS: ORAL
“thrush” “glossitis” “stomatitis”
“cheilitis” “perleche”

SYMPTOMS: VAGINITIS &
BALANITIS
“VAGINITIS = female”
“BALANITIS = male”

“Esophageal growth”
OTHERS: gastritis, peritonitis, enteric and perianal disease
SYMPTOMS: ALIMENTARY

CANDIDIASIS IN NAILS

CANDIDIASIS IN DIAPER RASH
“Candida may come from fecal origin”

SYSTEMIC INVOLVEMENT
Urinary tract
Endocarditis
Meningitis
Septicemia
Latrogenic candidemia
Dissemination to other organ systems

DISSEMINATED CANDIDIASIS
originate at a gastrointestinal site
CA enters epithelial microvilli through persorption of yeast cells
or by germination (a,c)
In both cases, organisms enter the vasculature (b,d) for
dissemination into tissues such as the kidney (e)
localizes in the cortex (f) where it grows as hyphae/
pseudohyphae
A vigorous host response occurs at this site consisting of both
mononuclear and polymorphonuclear leukocytes
Virulence factors (adhesins, morphogenesis, switch phenotypes,
antioxidant proteins and invasive enzymes) promote the invasion
of the organism

ALLERGIC CANDIDIASIS
Eczema
Asthma
Gastritis

LABORATORY DIAGNOSIS:
CADIDIASIS
Direct microscopic
examination
Specimen for examination can
be sputum, skin scrapings,
vaginal swabs, biopsy material,
from any types of organs or
even in blood.
The specimen is treated with
1-2 drops of 10-20% KOH.

LABORATORY DIAGNOSIS:
CADIDIASIS
The presence of the capsule
and budding yeast cells are
considered as the positive
results.
Aside from KOH, other
stains can be used such as
India ink and Papanicolaou
stain.

GERM TUBE TEST
Most isolates of
C. albicans produce a
hyphal growth from
blastospores when
they are suspended in
serum at 37°C for 2-3
hours.

IN CULTURE...
SDA at either room temperature or at 37°C
Colonies: usually develop in 2-3 days as
white, typical yeast colonies
In vitro: monomorphic, growing as non
encapsulated yeast cells at any temperature

IN CULTURE...

FROM CORN MEAL AGAR

TREATMENT OF CANDIDIASIS
Most localized, cutaneous, candidiasis infections may
be treated with any number of topical antifungal
agents (eg, clotrimazole, econazole, ciclopirox,
miconazole, ketoconazole, nystatin).
For Candida onychomycosis, oral itraconazole
(Sporanox)
For Genitourinary tract candidiasis, VVC can be
managed with either topical antifungal agents or

TREATMENT OF CANDIDIASIS
Caspofungin acetate (Cancidas) as a 70-mg
loading dose is followed by 50 mg/d IV for a
minimum of 2 weeks after improvement or
after blood cultures have cleared.
Chronic mucocutaneous candidiasis is treated
with oral azoles, either ﬂuconazole (Diﬂucan)

ASPERGILLOSIS
One of the largest of the fungal genera
Hundred of species have been recorded
The most important species:
A. fumigatus
A. ﬂavus
A. niger

ASPERGILLUS FUMIGATUS
Aspergillus fumigatus
identiﬁed according to
the pattern of
conidiophore
development,
morphologic features
and color of the
conidia

IMPORTANT PARTS

SPECTRA OF ASPERGILLOSIS
Toxicity due to ingestion of contaminated foods
Allergy and sequelae to the presence of conidia or transient
growth of the organism in body oriﬁces
Colonization without extension in preformed cavities and
debilitated tissues
Invasive, inﬂammatory, granulomatous, necrotizing disease of
lungs and other organs
Systemic and fatal disseminated disease

ALLERGIC ASPERILLOSIS
Allergic aspergillosis maybe benign early on and
severe as the patient grows older
In secondary colonization, a chronic clinical
situation may exist with little distress except
occasional bout of hemoptysis and some
pathological changes in the lungs that may lead to
the formation of fungus ball.

ALLERGIC ASPERILLOSIS
SKIN FUNGAL SPECIMEN
IN THE TISSUE

SYSTEMIC ASPERGILLOSIS
An extreme serious disorder that is usually
rapidly fatal unless diagnosed early and treated
aggressively
The status of the host’s immune system
contributes to the prognosis of the patient

SYSTEMIC ASPERGILLOSIS
FUNGUS BALL/
ASPERGILLOMA

Disease Etiologic Factors
Mycotoxicoses Ingestion of contaminated food
products
Hypersensitivity
peumonitis
Allergic bronchopulmonary
disease
Secondary
colonization
Colonization of preexisting
cavity (pulmonary abscess)
without invasion into
contiguous tissue
Systemic disease Invasive disease involving
multiple organs

DISSEMINATED ASPERGILLOSIS
Aerosols of Aspergillus fumigatus conidia are inhaled and
travel to the alveoli
In the healthy host, alveolar macrophages (AM) phagocytose
and kill the organism after swelling of the conidium, an
essential pre-germination stage
The production of reactive oxygen intermediates by AM is
required to eliminate the organism, but
polymorphonuclear cells (PMNs) also contribute
In the immunosuppressed patient, reduced numbers of PMNs
and inefﬁcient AM allow growth of the fungus
Consequently, the conidia germinate and escape from the AM

LABORATORY DIAGNOSIS
Aspergillosis is easy to isolate and identify....BUT!
also important to distinguish a true pathogen
from a contaminant
If sputum sample is to be collected, it is expected
to be thick and gelatinous
In invasive sampling, lung aspirates or tissue
biopsy is used

LABORATORY DIAGNOSIS
Direct microscopic examination will show
hyaline, dichotomously branched and septate
hyphae
Occasionally in sputum, in cases of pulmonary
aspergillosis, one may also sees very small, rough
walled spores (3-4 um in diameter).

PULMONARY ASPERGILLOSIS

TREATMENT
Amphotericin B was used
for many years BUT!!! with
disappointing results
In 1990 itraconazole was
introduced as a new broad
spectrum anti-fungal agent.

ZYGOMYCOSIS/PHYCOMYSIS
Class Phycomycetes
Rhizopus
Absidia
Mucor
They formed coenocytic hyphae and reproduce
asexually by producing sporangiosphores within
which develops sporangiospores

ZYGOMYCOSIS/PHYCOMYSIS
Repeated isolation of the
organisms from consecutive
specimens provides strong
evidence that the organisms
may be relevant, even though
coenocytic hyphal elements
are not seen in
histopathologic examination
of tissue.

MUCORMYCOSIS (ORAL CAVITY)

CATEGORIES COMMENTS
Rhinocerebral It is the most frequent presentation
ketoacidosis.
overall and classically affects diabetics with
Usually presents with facial and/or eye pain, proptosis and progressive signs of
involvement of orbital structures (muscles, nerves and vessels).
Common complications include cavernous sinus and internal carotid artery
thrombosis.
Pulmonary It occurs most frequently among neutropenic patients.
It presents with nonspeciﬁc symptoms such as fever, cough and dyspnea;
hemoptysis may occur with vascular invasion.
Radiological presentation includes segmental consolidation that progresses to
contiguous areas of the lung, with occasional cavitation.
Gastrointestinal Usually affects patients with severe malnutrition
May involve the stomach, ileum, and colon
Clinical picture mimics intra-abdominal abscess. The diagnosis is often made at
autopsy.
Cutaneous It has been
burns.
reported with minor trauma, insect bites, no sterile dressing, wounds, and
The necrotic lesions progressively evolve from the epidermis into dermis and even
muscle.
Others Heart, bone, kidneys, bladder, trachea, and mediastinum

DIRECT EXAMINATION: ZYGOMYCOSIS
A rapid diagnosis is critical
Fungal elements are usually not numerous in discharges
Scrapings from the upper turbinates, aspirated material
from sinuses, sputum in pulmonary disease, and biopsy
material mounted in 10% KOH typically contain thick-
walled, refractile hyphae 6-15 um in diameter
Swollen cells (up to 50 um) and distorted hyphae may be
present

IN CULTURE...
Sabouraud dextrose agar:
Incubate at 30°C
DON’T: cycloheximide =
sensitive
Sterile bread:
for recovery of Zygomycetes
when other media fail
WHY bread???

TREATMENT
Control of the diabetes
Aggressive surgical
debridement of involved tissue
High doses of amphotericin B
are recommended

Understanding Opportunistic Mycoses and Their Treatment

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