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

1. MYCOLOGY
Dr. Ashish V. 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
immunosupressed and those on
steroid treatment


4. BASICS
Fungi are eukaryotes
 Have multilayered cell wall
 Bilayered cell 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
 Pityriasis versicolor
 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’s dextrose agar


19. Pityriasis versicolor
Areas of depigmentation or
hyperpigmentation on skin of trunk,
abdomen and upper limbs
 Diagnosis by skin scrapings – yeasts
seen


21. Tinea nigra
Infection of palms
 Black or brownish lesions
 Hyphae and 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 tinea or 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 accd to
source
Anthrophilic – human beings eg tinea
rubrum
 Zoophilic – animals – M canis
 Geophilic - soil


32. diagnosis

ectothrix
KOH mount
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
madura foot
 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 demostration of sclerotic bodies
on histology or KOH mount

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

46. 
Diagnosis by demostration of asteroid bodies

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

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

Oppurtunistic pathogens – 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. Oppurtunistic systemic mycoses

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

61. Aspergillosis

62. Enough of negativity……..