Mycology - all about fungi

This is a series of lectures on microbiology, useful for undergraduate medical and paramedical students..

1. MYCOLOGY
Dr. AshishV. Jawarkar
M.D.

2. Warning!!!!!!

3. Mycology
Greek –mukes–fungus
Candida was described early as 1839
But fungi were not studied till recently
because most infections are mild
After bacterial infection control
developed, fungal infections became
more common
Fungi cause serious infections in
immunosupressedand those on
steroid treatment

4. BASICS
Fungi are eukaryotes
Have multilayered cell wall
Bilayeredcell membrane

5. Types
Depending on cell morphology
Yeasts
Molds
Dimorphic

6. Yeast
Unicellular, reproduce by budding

7. Examples of yeasts
Candida
Cryptococcus neoformans
malassezia

8. Molds

9. Examples of molds
dermatophytes

10. Classification according to
type of infection
Superficial infections
Subcutaneous infections
Systemic infections

11. Superficial mycoses
Affect skin, hair, nails and mucous
membranes
Include
Candidosis
Pityriasisversicolor
Tinea
Pedra
dermatophytosis

12. Candidosis
Usually superficial –infect skin, nails
and mucous membranes
Systemic infection in
immunosupressed
Yeast and hyphae–dimorphic fungus

14. Lab diagnosis
Wet films
Gram stain –budding gram positive
cells
Sabourand’sdextrose agar

19. Pityriasisversicolor
Areas of depigmentationor
hyperpigmentationon skin of trunk,
abdomen and upper limbs
Diagnosis by skin scrapings –yeasts
seen

21. Tineanigra
Infection of palms
Black or brownish lesions
Hyphaeand budding yeasts on smear
Cultured on SDA, green to black
colonies

24. Piedra
Infection of hair
Irregular nodules on hair shaft

27. Dermatophytosis
Skin, hair and nails
a/k/a tineaor ring worm
About 40 of them are known
Classified on the basis of type of
colony on SDA and spores they
produce

28. spores

29. Classification
Trichophyton–only micro
microsporum–both micro and macro
Epidermophyton–only macro
Colonies
Trichophyton–powdery
Microsporum–cotton like –with
pigmentation
Epidermophyton–greenish yellow
color

30. Ringworm

31. Epidemiology
Classified into three types accdto
source
Anthrophilic–human beings egtinea
rubrum
Zoophilic–animals –M canis
Geophilic-soil

32. Lab diagnosis
KOH mount
ectothrix
endothrix

33. Lab diagnosis
SDA
trichophyton

34. epidermophyton

35. microsporum

37. SUBCUTANEOUS MYCOSES

38. Mycetoma
Infection of subcutaneous tissue of
foot
Reported from Madurai–a/k/a
madurafoot
Multiple sinuses are seen in foot
discharging pus onto surface
Pus contains ‘sulfur granules’which
are colonies of fungi

41. Chromoblastomycosis
Cauliflower like lesions on lower limb
Fungi are in soil, enter at site of
trauma
Seen in bare foot agricultural workers

43. Diagnosis by demostrationof sclerotic bodies
on histology or KOH mount

44. SPOROTRICHOSIS
Fungus found on thorns
Infection seen in gardeners
Nodules are seen in skin, along
lymphaticsand lymphnodes
Upper limb
Caused by fungus Sporothrix
schenckii

46. Diagnosis by demostrationof asteroid bodies

47. RHINOSPOROIDOSIS
Polyps around nose, mouth or eye
Majority cases from Sri lanka
Agent RhinosporoidiumSeeberi

50. SYSTEMIC MYCOSES

51. Systemic mycoses
Affect multiple body systems, usually spread through
blood stream
Two groups
True pathogens –cause disease in healthy
•Histoplasma
•Blastomyces
•P. marneffei
Oppurtunisticpathogens –cause disease in
immunosupressed
•Candida
•Aspergillus
•Zygomycetes
Other
•Cryptococcus neoformans

52. CRYPTOCOCCUS
NEOFORMANS
Yeast
Found in feces of pigeons/birds
Most often seen in patients with HIV

53. Fungus is inhaled
Can cause pneumonia, meningitis,
skin ulcers etc.
Diagnosis by demonstration of
capsulated budding yeast in
CSF/sample
India ink is used to demostrate
capsule

55. Negative staining –India ink

56. Histoplasma
Grows as mold in nature, yeast in
tissues
Most common in USA
In India found in west bengal
Found in bird feces
Inhaled –lung infection, may spread

59. Oppurtunisticsystemic mycoses

60. Candidosis
Common in immunosupressed
Can affect kidneys, liver, spleen
Diagnosis by blood culture, tissue
biopsies

61. Aspergillosis

62. Enough of negativity……..