Subcutaneous Mycoses_prt.2 Flashcards
- Madura Foot or Maduromycosis, mycetoma caused by a fungus.
➢Eumycetoma
– mycetoma caused by an actinomycete;
more invasive and spreading to the underlying tissue
➢Actinomycetoma
➢Chronic subcutaneous infection induced by traumatic
inoculation with any of several saprophytic species of fungi or
actinomycetous bacteria that normally found in soil.
➢Clinical features: local swelling, interconnecting, often draining, sinuses or fistulae that contain GRANULES, which are microcolonies of the agent embedded in tissue material.
EUMYCETOMA
Eumycetoma
• Etiological Agents: a wide range of fungi…
Most common:
Madurella mycetomatis
M. grisea
Scedosporium boydii
Scedosporium apiospermum,etc.
• MOT: Snake bites, knives, splinters, thorns, and insect bites
• WHO-recognized neglected tropical disease with significant disease burden, 2016
Eumycetoma
• Distribution: Barefoot walking populations of tropical/subtropical countries – India, West Africa (Senegal, Sierre Leone). Where countries are endemic – part
of the “Trans-African Belt” or “mycetoma belt.”
Rare in developed nations.
Eumycetoma
– the hallmark of mycetoma
➢GRAINS
➢ Sinuses discharge serosanguinous fluid containing granules, which vary in size, color, and degree of hardness, depending on species.
Eumycetoma
➢ **Start out as a small hard painless nodule, ** overtime begins to soften, and ulcerate to discharge a viscous, purulent fluid containing grains.
Infection slowly spreads to adjacent tissue, including bone, causing considerable deformity.
Eumycetoma
Eumycetoma
Classified based on the type of grain produced:
• Dark and black grains:
Madurella mycetomatis
Exophiala jeanselmei
Eumycetoma
Classified based on the type of grain produced:
White and pale unstained grains:
Acremonium spp.
Scedosporium apiospermum
Scedosporium boydii
Eumycetoma
Classified based on the type of grain produced:
Yellow-brown:
Nocardia brasiliensis
Nocardia otitidiscaviarum
Actinomadura madurae
Streptomyces somaliensis
Eumycetoma
Classified based on the type of grain produced:
• Yellow:
Pleurostomophora ochracea
showing numerous draining sinuses.
There is destruction of bone, distortion of the foot, and hyperplasia at the openings of the sinus tracts.
draining sinus (cut open in this preparation) containing black grains
Mycetoma
Granules are composed of
septate fungal hyphae, 2-6 um
or greater, dematiaceous (black grain) or hyaline (pale or white grain)
Eumycetoma
➢ **Start out as a small hard painless nodule, ** overtime begins to soften, and ulcerate to discharge a viscous, purulent fluid containing grains.
Infection slowly spreads to adjacent tissue, including bone, causing considerable deformity.
Eumycetoma
• Culture shows the typical brown diffusible pigment (pyomelanin) in the agar.
• Colonies are slow growing, flat and **leathery at first, white to yellow to Browmish, ** folded and heaped with age and the formation of aerial mycelia.
Madurella mycetomatis
• A brown diffusible pigment is characteristurly______
can be distinguished from Madurella grisea by growth at 37°C and its inability to assimilate sucrose.
Mucetomatis
showing phialides (rarely seen as most isolates are sterile);
• Two types of conidiation have been observed:
• First - being flask-shaped phialides that bear rounded conidia
• Second - being simple or branched conidiophores bearing conidia (3- 5um) with truncated bases.
• The optimum temperature for growth of this mold is 37°C.
M. mycetomatis
MYCETOMA
Colonies are **fast growing, ** greyish-white, suede-like to downy with a greyish-black reverse.
Scedosporium (Pseudallescheria) boydii
• Cleistothecia - non-ostiolate
• Ascocarps - yellow to brown to black, spherical, 50-200 um in diameter, submerged in the agar, composed of irregularly interwoven brown hyphae.
• Crushed cleistothecia release numerous, faintly brown, ellipsoidal ascospores,
4-5 x 7-9 um in size.
Scedosporium (Pseudallescheria) boydii
Crushed cleistothecium of ______mounted in Melzer’s reagent, showing dextrinoid reaction of
ascospore
P. boydii
• Fascicles (bundles) of conidiophores bound together in synnemata (wheat sheaf appearance)
Scedosporium apiospermum/S. boydii
The conidial states of S. boydii and
S. apiospermum are morphologically indistinguishable. But:
•_______ - **homothallic, ** smaller cleistothecia (50-200um)
•________- heterothallic (requires mating of two strains), larger cleistothecia (140-480um)
S. boydii
S. apiospermum
Colonies: slow growing, compact, moist at first becoming powdery, suede-like or floccose with age.
White, gray, pink, rose or orange in color.
• Morphology: fine, hyaline hyphae produce mostly AWL-SHAPED ERECT PHIALIDES with inconspicuous collarettes.
Globose-cylindrical conidia aggregated at the apex.
Acremonium species
> Is a chronic infection, initially flat but developed into discolored, cauliflower-type polypoid masses (varying in size) of the nasal mucosa
Rhinosporidiosis
- nose, nasopharynx, or soft
palate, caused by_____
> Produces large spherules in lesions and in epithelial cell tissue culture
Spherules - the form that the fungus takes in tissue; large, thick-walled sporangia, packed with thousands of endospores
• Histopathology: Epithelial hyperplasia and cellular infiltrates of neutrophils, lymphocytes, plasma cells, and giant cells
Rhinosporidium seeberi.
Mature spherule with endospores typical of _______.
100 to 450 micrometer in diameter with a thick chitinous wall; **sporangiospores stain basophilic, ** 7 to 9 pm in diameter; if there is rupture of sporangia in the stroma, an intense granulomatous response can be seen.
Rhinosporidiosis
> _________ belongs to class
Mesomycetozoea (a new group of microorganisms which lie between fungi and animals, usually parasites of fish and other animals)
> Endemic in India, Srilanka, & Africa
> MOT: bathing in stagnant ponds in which animals also bathe; rarely by autoinoculation; rarely by hematogenous spread
> Other rare sites: conjunctiva, mouth, larynx, genitalia, & skin
Tx: Excision of the lesions
R seeberi
Entomophthoromycosis
> Rare subcutaneous/mucocutaneous mycosis in tropical/subtropical areas
_______ in Gk means “insect” - recognized as parasites infecting insects
2 distinct types:
____________
› rhinoentomophthoromycosis
____________
entomophthoromycosis basidiobolae
• Are zygomycetes; orders:
Mucorales, Basidiobolales, & Entomophthorales
Entomon
> Conidobolomycosis
> Basidiobolomycosis
Entomophthoromycosis
Order Mucorales: MRRAACS
> subcutaneous zygomycosis (vascular invasion)
Mucor
Rhizopus
Rhizomucor
Absidia
Apophysomyces
Cunninghamella
Saksenaea
Entomophthoromycosis
Order Basidiobolales:
•_______: Found on the skin & GIT of amphibians & reptiles, dung of frogs
Basidiobolus
Entomophthoromycosis
Order Entomophthorales:
•________:
> Saprobes in soil, reproduce within their host insects
Conidiobolus
Entomophthoromycosis
Conidobolomycosis
• Caused by_________
• a chronic rhinofacial subcutaneous infection
- originates in the nasal sinuses and extends to the subcutaneous tissue of the face resulting in disfigurement among healthy hosts.
Conidiobolus coronatus
Entomophthoromycosis
Basidiobolomycosis
• Caused by________
• Affects limbs, trunk, buttocks, GIT system
• Affects both immunocompetent & immunocompromised patients
Basidiobolus ranarum
Entomophthoromycosis
• Tissue biopsy: Focal clusters of inflammation, with eosinophils & coenocytic or sparsely septate hyphae often surrounded with eosinophilic Splendore-Hoeppli material
Conidobolomycosis
• Caused by Conidiobolus coronatus
Entomophthoromycosis
• Tissue biopsy: Multiple granulomata, giant cells, and eosinophils & numerous branching, broad coenocytic or sparsely septate hyphae surrounded by an eosinophilic Splendore-Hoeppli sheath
Basidiobolomycosis
• Caused by Basidiobolus ranarum
Entomophthoromycosis
> Culture: Flat, glabrous, and colorless or gray to yellow colony on SDA, radial folds and thin aerial hyphae
Conidobolomycosis
• Caused by Conidiobolus coronatus
Entomophthoromycosis
> Culture: Flat, glabrous, colorless/brownish colonies with radial folds, covered with short, white aerial mycelium
Basidiobolomycosis
• Caused by Basidiobolus ranarum
> Morphology: Large, spherical conidia with hairlike appendages are borne singly on the tips of conidiophores and forcibly ejected at maturity
Conidiobolus coronatus
> Morphology: Large, spherical conidia with hairlike appendages - borne singly on the tips of conidiophores & forcibly ejected at maturity, wide hyphae, chlamydospores, spherical smooth-walled zygospores (in older cultures)
Basidiobolus ranarum
The term “______” is proposed to summarize all fungal infections caused by Mucorales and species of Basidiobolus and Conidiobolus.
coenocytic hyphomycosis
A chronic subcutaneous mycosis caused by Lacazia loboi
LOBOMYCOSIS
• A yeast-like fungus causing infections in humans and bottle-nosed dolphins
> Saprophytic in water
> Transmitted to the vulnerable host via contact - cutaneous trauma, insect bite, wound cut enhances entry of fungus; no person-to-person transmission
907 cases globally, mostly from tropical zones, aquarium employees and farmers (or remain undiagnosed)
Lacazia loboi
> Terms: Jorge Lobo’s disease, Lacaziosis, keloidal blastomycosis
> Endemic to the Amazon rainforest, Brazil
LOBOMYCOSIS
> Lesions: slowly progressing keloidal nodules - ulcerative or verrucous; hypo-/hyperpigmented macules/papules - pruritic or a burning sensation, disseminated or isolated in lower limbs, ears, upper limbs, 8 head
Lobomycosis
> Mistaken for cutaneous leishmaniasis, leprosy, sporotrichosis, Paracoccidioidomycosis, etc.
Lobomycosis
Lobomycosis
•_______for histological analysis — the gold standard. Cannot grow on culture
•Yeast cells are identified by H&E & Gomori-Grocott methenamine silver stains, Scotch test, KOH, molecular test.
• Histopath: hyperkeratosis, collagen fibroplasia, vascular neoformation, & diffuse inflammatory infiltrate with lymphocytes, epitheloid cells, giant cells, & hemosiderin-laden histiocytes.
Biopsy
KEY Diagnosis: ROUND THICK-DOUBLE-WALLED YEASTS SINGLY or in INTERCONNECTED CHAINS
LOBOMYCOSIS
❑Is the MOST NEGLECTED tropical disease.Acre in Brazil with highest prevalence.
❑Recommendations: Be included in the list of reportable diseases & adopt multibacillary multidrug therapy for the standard treatment of this disease
LOBOMYCOSIS
