This document provides an overview of subcutaneous mycoses. It discusses several types including mycetoma, sporotrichosis, rhinosporidiosis, chromoblastomycosis, phaeohyphomycosis, and lobomycosis. For each condition, it summarizes the causative agent, clinical features, pathogenesis, diagnosis including direct examination and culture techniques, and treatment approaches. The document emphasizes that these infections usually follow trauma and develop subcutaneously at the site of inoculation, presenting with characteristic clinical features like tumefaction, draining sinuses, and presence of grains or granules.

1. iii sem smsmc
SUBCUTANEOUS
MYCOSIS
Mycetoma
Dr. Dinesh Jain
Assistant Professor
Deptt. of Microbiology
SMS MC Jaipur

2. INTRODUCTION
 Heterogenous group of fungal infections
which are characterized by development of
clinical lesions in subcutaneous tissues at
the site of inoculation of etiological agents.
Disease process starts following a trivial
trauma, which is the sole source of
infection.
mycology aruna, Microbiology

3. 16/12/07
INTRODUCTION
 Usually follow trauma.
 Lesions develop at the site of implantation of
the etiological agent in the subcutaneous
tissue.
 Includes – Mycetoma
- Sporotrichosis
- Rhinosporidiosis
- Chromoblastomycosis
- Phaeohyphomycosis
- Lobomycosis

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MYCETOMA
 Chronic, slowly progressive granulomatous
infection of skin & subcutaneous tissues with
the involvement of underlying fasciae &
bones commonly affecting the extremities.
 Reported by Gill from Madurai, S.India.
 Maduramycosis or Madura foot.
 Tropical & subtropical countries of Asia ,
Africa, Central & S.America.

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Classification of Mycetoma
 Based on the causative agent
True Fungi – Eumycetoma
Aerobic filamentous bacteria (actinomycetes) -
Actinomycetoma
 Based on the colour of grains
Bacterial agents – white to yellow grains except
Actinomadura pelletieri (red or pink)
Fungal agents – black as well as white grains.

6. ETIOLOGY
 Fungal agents (25 agents)-saprotrophic
environmental fungi-Deuteromyctes(10
agents) or Ascomycetes(3 agents) cause
white grain mycetoma
 Others cause black grain Mycetoma
smsmc micro

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Colour/texture of grains in Mycetoma
of various etiology
White to yellow/soft Brown to black Red
Nocardia
asteroides/brasiliensis
Madurella
mycetomatis/hard
Actinomadura
pelletieri
Acremonium/Fusarium
/Aspergillus nidulans
Madurella grisea/soft
Actinomadura madurai Phialophora
jeanselmei/soft
Streptomyces
somaliensis
Curvularia
geniculata/hard
Pseudollescheria
boydii

8. smsmc
Epidemiology
 More prevalent in developing countries,
especially in the rural areas.
 Young men 20 to 40 yrs of age
 Field workers, farmers – prone to thorn prick
injury & trauma.
 Prevalence in world : Eumycetoma (40%)
Actinomycetoma (60%)

9. ssmsmc
Pathogenesis & Pathology
 Causative agent present in soil
 Accidental trauma by thorns or splinter injury
 Minor trauma & skin abrasions
 Mycetoma of ear – use of wicks for removal
of earwax.
 Mycetoma of back – carrying goods like
wood, grain bags, stones, etc
 Mycetoma of the head & neck – bundles of
wood

10. smsmc
Pathogenesis & Pathology
 Lesion begins as a small subcutaneous
swelling of the foot, which enlarges burrowing
into the deeper tissues & tracking to the
surface as multiple sinuses discharging
viscid, seropurulent fluid containing granules
or grains which are microcolonies of the
causative agent.

11. smsmc
Clinical features
 Characterised by a triad of
clinical features irrespective
of the causative agent:
1. Tumefaction – tumor like
swelling
2. Multiple draining sinuses
3. Presence of grains or
granules in sinuses.

12. smsmc

13. smsmc
Diagnosis
 Radiodiagnosis – Xray, CT, MRI.
 Laboratory diagnosis
- Proper h/o patient
- Gross examination of lesion by a microbiologist
Specimen – grains or granules
- pus / exudates or biopsy
Lesions cleaned with antiseptics & the grains
collected by pressing the sinus from the
periphery.
Gross examination of grains – size, shape,
texture, colour

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Direct Examination
 KOH mount – grains
Eumycetoma : 2-6µ, wide interwoven hyphae
with large, swollen cells (chlamydospores) at the
margin of the lesion.
Actinomycetoma : filaments with a diameter of
0.5 - 1µ, coccoid to bacillary forms.
If hyphae seen on KOH mount, use special
stains.

15. smsmc
Direct Examination
 Gram stain – gram +ve
branching filamentous
bacteria embedded in the
grain material.
 Modified Acid fast staining
with 1% sulphuric acid – pink
colored filamentous bacteria
i.e. Nocardia Sps whereas
other actinomycetes are
non- acid fast.

16. smsmc
Culture
 Different sets of media – both possibilities of
fungi & bacteria .
 When Actinomycetoma is suspected on direct
examination - wash grains several times with
NS & then inoculate on SDA without
antibiotics, BA, LJ & BHIA.
 When Eumycetoma is suspected – wash
grains several times in NS with antibiotics(Pn)
& inoculate it on SDA with antibiotics.
- actidione not added.
- incubated at 25° & 37°C

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Treatment & prophylaxis
 Eumycetoma – Oral Ketoconazole &
Itraconazole
AMB for Madurella & Fusarium species.
 Actinomycetoma – Sulfonamides,
Tetracyclines, Streptomycin, Amoxycillin,
Clavunate & Amikacin
 Protracted case – Surgery (debridement with
skin graft)

18. smsmc
micro
Botryomycosis
 Similar condition caused by bacteria like
S.aureus, P.aeruginosa, CONS, E.coli.
Pr.vulgaris etc.
 2 types : cutaneous
visceral – ill debilitated pts

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SPOROTRICHOSIS
 Caused by Sporothrix schenckii, a dimorphic
fungus.
 Most common in USA.
 Found on plant, thorns & timber
 Infection is acquired through thorn pricks or
other minor injuries

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Pathogenesis & pathology
 Spreads from primary site
to the regional LNs through
lymphatics
 Mostly involves upper limbs
 Pyogranulomatous reaction
 Clinical features - Nodules
on the skin, subcutaneous
tissue and in the LNs which
later soften & ulcerate.
Lymphocutaneous sporotrichosis

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Laboratory Diagnosis
 Specimens – pus, exudate & aspirate from
nodules.
- curettage or swabs from open lesions.
Direct Examination
 Gram’s stain – gram+ve, irregularly stained
yeast cells.
 CFW – very useful.

22. smsmc micro
Direct examination
 Tissues – organisms appear as cigar shaped
bodies (yeast cells) 3-5µ in diameter.
 “Asteroid bodies” in the lesion – central
fungus cell surrounded by a refractile
eosinophilic halo, called “ Splendore-Hoeppli”
phenomenon : due to immune complex
deposition around the organism.

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Culture
 Inoculated on 2 sets of SDA, BHIA
 Incubated at 25°& 37°C.

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LPCB mount from Culture
 septate hyphae - very thin & carry flower like
clusters of small conidia on delicate sterigmata.

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Treatment & Prophylaxis
 Saturated solution of KI – drug of choice
 Oral Ketoconazole or Itraconazole
 AMB – disseminated & CNS disease.

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RHINOSPORIDIOSIS
 Caused by a hydrophilic protist,
Rhinosporidium seeberi
 1st identified in Argentina, but majority of cases
occur in India and Sri lanka.
 High incidence among people who frequently
bathe along with domestic animals in ponds,
tanks, lakes

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Clinical Features
 Chronic granulomatous disease of mucous
membrane.
 Characterised by the development of friable
polyps in the nose, mouth or eye.
 Miscellaneous forms –
Buccal cavity,vagina,
vulva, penis, urethra
or rectum

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Laboratory Diagnosis
 Cannot be cultured
Direct Examination
 FNAC, Biopsy of lesion, Nasal washing
- Contains sporangia
filled with thousands of
sporangiospores(6-9µ)
embedded in a stroma
of connective tissue &
capillaries

29. smsmc micro
Treatment & Prophylaxis
 Radical Surgery:- Excision/ Electrocautery
 Medical therapy :- not useful
DDS (widely used)
 Recurrence common

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CHROMO BLASTOMYCOSIS
 Caused by dematiaceous (pigmented) fungi
 Commonest fungi - Fonsecaea Species
Phialophora verrucosa
Cladosporium carrionii
 Also called as Verrucous dermatitis

31. smsmc micro
Clinical features
 Soil saprobes enter the skin by traumatic
implantation and lesions develop slowly around
the site of implantation
 Warty cutaneous nodules which resembles
flouts of cauliflower - Verrucous dermatitis
 Frequently ulcerate
 Confined to the subcutaneous tissue of the feet
and lower legs

32. smsmc micro
Laboratory Diagnosis
Direct Examination
Dry crusty material from the surface of the
lesions
1. KOH w/m –
dark brown, multicellular structures, 5-12μ in
diameter that divide by transverse septation.
-Called sclerotic bodies, medlar bodies, copper-
pennies bodies or muriform cells

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Sclerotic bodies - KOH
Sclerotic bodies - tissues

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Direct examination
Medlar bodies - characteristic tissue form -
facilitates survival of organism in host tissues.
2. Tissue Stains - for Biopsy specimens
HE, Giemsa & Fontana- Masson
- Sclerotic bodies very well seen
Fungal culture - SDA with actidione and
antibiotics

35. smsmc micro
Treatment & Prophylaxis
 Responds poorly to available therapies.
 Cryotherapy, Thermotherapy, Laser
therapy,Chemotherapy and Surgery.
 Flucytosine (commonly used drug)
 Itraconazole, Fluconazole, Terbinafine
*Relapses are frequently seen

36. smsmc micro
PHAEOHYPHOMYCOSIS
 Seen in debilitated & immunodeficient hosts.
 Causes subcutaneous & systemic infection.
 Caused by dematiaceous fungi. Commonest
genera involved - Alternaria, Bipolaris,
Curvularia, Exophiala, Phialophora, etc.

37. smsmc micro
Clinical Features
 Clinical types:
1. Brain abscess caused by Cladosporium
2. Subcutaneous or intramuscular lesions with
abscess or cysts - single circumscribed
lesion with a central cavity filled with pus
and surrounded by a fibrous wall
3. Cutaneous lesions

38. smsmc micro
Laboratory Diagnosis
Specimen
 Aspirates from cysts
 Curreting from plaques, nodules and drained
abscess
Direct Examination
KOH mount
- Pigmented hyphae 3-4µ in dia.

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Fungal Culture
 SDA with actidione at 25º & 37ºC.
Treatment & Prophylaxis
 Local excision for subcutaneous forms
 Invasive infections – I.V. AMB + Oral
Flucytosine.

40. smsmc micro
LOBOMYCOSIS
 Caused by Lacazia loboi
(Hydrophilic fungus) : exists
only as yeast cells.
 Involves exposed parts
 Presence of macule, papule,
keloid, verrucous, nodular
lesions or plaques & tumors.
 Lesions are painless with
slight pruritis

41. smsmc micro
Laboratory Diagnosis
 Direct Examination of curettage / biopsy -
crushed
a. KOH w / m
b. CFW
- spheroid, yeast - like cells, 5 -12µ
- thick - walled & multinucleate.
- form chain with cells joined by bridges.
c. HE – may show ‘asteroid bodies’
• Culture – cannot be cultured

42. smsmc micro
Fontana Masson stain

43. smsmc micro
Treatment & prophylaxis
 No effective medical treatment
 Complete excision
 Cryosurgery.