3. MYCOLOGY??
It is a branch of Microbiology that deals with study
of FUNGI.
Mycology derived form the Greek word “Mycos” meaning
“FUNGUS”
Medical Mycology deals with the Etiology, Pathogenesis,
Detection, Prevention and Treatment of FUNGAL
INFECTION
4. FUNGI
1. Fungi are Eukaryotic Protista that differ from bacteria and other
Prokaryotes.
CHARACTERISTICS
*They posses rigid cell wall containing CHITIN,
MANNAN , other POLYSACCHARIDES.
*Their Cytoplasmic Membrane Contains STEROL.
*They posses true nuclei with a nuclear membrane
and paired chromosomes.
*They divide Asexually, Sexually or by both
processes.
*They may be Unicellular or
Multicellular.
5. CLASSIFICATION OF FUNGI
• Based on Morphological Forms
• Based on Sporulation
• Based on type of infection
• Based on site of Infection
prodced by fungus.
7. CLASSIFICATION BASED ON MORPHOLOGICAL
FORMS
1.YEAST
They are unicellular fungi.
They grow as round or oval shape.
They reproduce by an asexual process
called Budding ,in which cell form
protuberance which enlarge and
eventually separate from the parent
cell.
8. Filamentous (HYPHAE like ) structures
are not seen in tissues or in culture.
They don’t produce Germ tube or
pseudohyphae.
SACCHAROMYCES CEREVISIAE
also known as BAKER’S YEAST OR
BREWER’S YEAST use for several
centuries for making Wine and Beer.
(a)CRYPTOCOCCUS NEOFORMANS in India pink
preparation (b) round , budding yeast cell
9. IN CULTURE ,Macroscopic appearance of
colony is Pasty,resembling bacterial
colonies.
Example -
SACCHAROMYCES CEREVISIAE CRYPTOCOCCUS NEOFORMANS
10. 2.YEAST LIKE FUNGI
• Unicellular Fungi
• Reproduce by Budding and Fission.
• They may be oval ,spherical forms
or filamentous forms.
Example-
• Colonies in culture Pasty Appearance.
In CANDIDA ,bud remains attached to
mother cell, elongates and undergo
repeated budding to form chains of
repeated cells called
PSEUDOHYPAHE
a) Oval budding cell of candida albicans in Gram Smear
b) Pseudohyphae
c) Oval, budding yeast cell
11. 3.FILAMENTOUS FUNGI OR MOULDS
SEPTATE
They grow as long branching
filament of 2-10 micron meter
width called “HYPHAE”
HYPHAE are of two types-
• HYPHAE having cross wall or
septa ,they are multicellular.
ASEPTATE
They devoid of septa called
Coenocytic(mutlinucleated).
12. HYPHAE grow continuously and
form a branching tangled mass of
growth called MYCELIUM.
• Reproduce by Asexual means (
Spore formation),some exhibit
Sexual reproduction.
Based on growth pattern in culture
medium ,the mycelia may be
categorised into two categories.
• AERIAL MYCELIUM-part of mycelium
which project above the surface of
culture medium
• VEGETATIVE MYCELIUM –part of mycelium
that grows on the surface of culture media.
13. HYPHAE may be Racquet shaped ,
Nodular, Pectinate,Spiral ,Root like or
Chandelier.
Example-
• DERMATOPHYTE
• ASPERGILLUS
• RHIZOPUS
• MUCOR
• PENICILLIUM
ASPERGILLUS MUCOR
RHIZOPUS
14. 4.DIMORPHIC FUNGI
They exist as Hyphal form Molds in the environment at ambient temperature
25.C and as a Yeast in human tissues at body temperature 37.C
Example-
• BLASTOMYCES DERMATITIDIS
• PARACOCCIDIOIDES
BRASILIENSIS
• COCCIDIOIDES IMMITIS
• HISTOPLASMA CAPSULATUM
• SPOROTHRIX SCHENCKII
• PENICILLIUM MARNEFFEI
HISTOPLASMA CAPSULATUM
MYCELIAL
(filamentous) form
YEAST form in tissue
section
15. 2.BASED ON SPORULATION
Also called Taxonomical basis of classification.
Classify on basis either they exhibit, whether Asexual or Sexual Spores.
They divide into 4 phyla on the basis of spores.
1.PHYLUM ZYGOMYCOTA they are
lower fungi produce Sexual Spores
Called ZYGOSPORE,and posses
Aseptate hyphae.
2.PHYLUM ASCOMYCOTA –they produce
Sexual Spores called ASCOSPORES ,and
posses Septate hyphae.
MUCOR
17. 3.BASED ON TYPE OF INFECTION
This depends on the pathogenic potential
of the fungus and the immune status of
the host.
1.Primary Pathogenic: caused by Dimorphic Fungi.
These infection may be either superficial,cutananeous,deep or
systemic fungal infection.
Example- COCCIDIOIDES IMMITIS.
2.Opportunistic pathogens: Fungi can
cause infections by various mechanism in
immunocompromised individual .
Example-
ASPERGILLOSIS,CRYPTOCOCCOSIS
18. 4.BASED ON SITE OF INFECTION
Infections occur as three major groups .
1.SUPERFICIAL MYCOSES- These involve
the superficial surfaces of body (dermis).
2.SUBCUTANEOUS MYCOSES-These
involve the subcutaneous tissues (dermis
and cutis).
3.DEEP OR OPPORTUNISTIC MYCOSES-
These are generally inseminated, generally
acquired by inhalation.
19. 4.SYSTEMIC MYCOSIS- these are
characterised by the involvement of multiple
organ . Mostly they are caused by the
SAPROPHYTIC FUNGI which spread by
inhalation of spores leading to Pulmonary
infection.
36. PATHOGENESIS
Fungal infection can be classified
according to the tissue involved
• Superficial Mycosis
• Subcutaneous Mycosis
• Systemic Mycosis
• Opportunistic Mycosis
37. SUPERFICIAL MYCOSES
Superficial mycoses are the fungal infections involving the
skin, hair, nail and mucosa.
examples include:
• Tinea versicolor
• Tinea nigra
• Piedra
• Dermatophytoses
38. Tinea versicolor / Pityriasis versicolor
• It is caused by lipophilic fungus
Malassezia furfur , which is
characterised by flat- round
scaly hypopigmented to hyperpigmented
patches of skin.
• Patches mainly seen on trunk region –
Chest, abdomen, and back.
• Lesions are confined to superficial
layers of skin
(stratum corneum)
39. Tinea nigra
• It is characterised by painless
, black, nonscaly patches
present on palm and sole .
• It is caused by a black
colored yeast like fungus
Hortaea werneckii.
• Females are more commonly
affected than males.
40. Piedra
• It is characterised by nodule
formation on the hair shaft, which
may either be black or white in
color.
• It is of 2 types;
Black piedra – characterised by
black colored , gritty,firmly
attached nodules on the hair
shaft.
It is caused by Piedraia hortae.
41. • White piedra –
It is characterised by soft, grey- white nodules
which are less firmly attached to the hair shaft.
It is caused by Trichosporon beigelii.
Trichosporon beigelii produces creamy white
colonies.
42. Dermatophytoses (or tinea or ringworm)
• It is the most common superficial
mycoses affecting skin, hair,and
nail.
• These include:
Trichophyton species: infect
skin, hair and nails
Microsporum species: infect
skin and hair
Epidermophyton species:
infect skin and nail.
43. Classification:
1. Anthropophilic dermatophytes
-cause mild lesions
-infect human only
- respond poorly to treatment
2. Zoophilic dermatophytes
- infect animals
3. Geophilic dermatophytes: soil
-humans get infected when contact with soil
44. . Lesions on nails: fungi invade the nails through
lateral/ superficial nail plates then spread
throughout the nail.
Types of clinical diseases:
• Tinea capitis
• Tinea corporis
• Tinea cruris
• Tinea pedis
• Tinea unguum
• Tinea barbae
• Tenia faciei etc.
45. SUBCUTANEOUS MYCOSES
Subcutaneous mycoses are the mycotic infections of the skin,
subcutaneous tissue and sometimes bone, resulting from
inoculation of saprophytic fungi of soil or decaying matter.
They are mainly confined to the tropics and subtropics.
46. Mycetoma
• Mycetoma, also known as maduramycosis
or madura foot is a chronic , slowly
progressive granulomatous infection of the
skin and subcutaneous tissues.
• Clinically manifested as a triad of swelling,
discharging sinuses and presence of
granules in the discharge.
47. Clinical features:
- more common in males than females
- lower limbs are commonly affected than
upper limbs.
- sometimes, underlying bones may be
involved.
Mycetoma is of two types:
1. Eumycetoma – caused by fungal agents
such as Madurella mycetomatis
2. Actinomycetoma – caused by bacterial
agents such as Nocardia.
48. Sporotrichosis
• It is also known as Rose picker’s
disease /Gardner’s disease/
carpenter’s diseae
• Caused by a thermally dimorphic
fungus, sporothrix schenckii.
• It is pesent on woods and plants
(rose) and mode of infection is
traumatic inoculation.
• It presents as subcutaneous
noduloulcerative lesions.
• It is common in tropical countries
with high humidity.
• It is also present in the soil and
hence walking barefoot also
predisposes to infection.
49. Chromoblastomycosis
• It refers to slow growing chronic
subcutaneous lesions caused by goup of
phaeoid fungi (i.e. darkly pigmented fungi)
that produce a characteristic morphology
called sclerotic body.
• Agents include : Fonsecaea, Phialophora
cladosporium and Rhinocladiella.
• It affects more males than females.
• Treatment: cryotherapy or laser therapy
followed by antifungals like itraconazole.
50. Rhinosporidiosis
• It is caused by Rhinosporidium
seeberi.
• It produces large friable polyps in
the nose (most common site),
conjuctiva, bronchus, larynx, eyes
genitalia.
• Source of infection : stagnant water
bodies.
- infection occurs via inhalation of
spores while bathing in
contaminated rivers and ponds.
51. • Fungi that are able to cause systemic illness in healthy people
are rare and confined to specific geographic location across the
world.
• Fungal infection of internal organs.
• Primarily involve the Respiratory System.
• Infection occurs by inhalation of air-borne conidia.
• Change in temperature determines the form. The fungus is a
mold when grown at 25 C but grows as yeast at body
temperature (Thermal Dimorphism).
SYSTEMIC MYCOSIS
52. PRIMARY SYSTEMIC
MYCOSIS
• Infections of internal organs of the body.
• Caused by dimorphic fungi
• The following are the types of Systemic mycosis :
1. Blastomycosis
2. Coccidiomycosis
3. Histoplasmosis
4. Paracoccidioidomycosis
53. 1. BLASTOMYCOSIS
• Caused by : Blastomyces dermatitidis.
• Inhalation of conidial spores.
• Primary infection : Pulmonary blastomycosis.
• Secondary infection : May spread to other organs including skin
(Cutaneous mycosis).
• Osteoarticular blastomycosis : Occurs in about 30% of patients
with the spine, pelvis, cranial bones, ribs and long bones most
commonly involved.
54.
55. Diagnosis
• Specimens : Bronchial secretion, urine, Scrapings from infection,
Sputum, Skin Scrapings, Bone marrow, Pleural fluid , Blood and
cerebrospinal fluid.
• Microscopic Examination :
- 10% KOH and Parker ink or calcofluor white mounts.(Skin, Body
fluids).
- Positive direct microscopy demonstrating characteristics yeast- like
cells.
• Culture : On Blood or Sabouraud agar must be incubated for several
weeks.
• Treatment :
- Amphotericin B
56. 2. Coccidiomycosis
• Caused by : Cocxidiodes immitis (Dimorphic)
• Inhalation of Arthrospores.
• Primary infection : Lungs.
• Secondary infection :
- May spread to other organs including skin.
- Other silent infections – severe pneumonia, lesions in
skin,
bones , joints, and meninges.
57.
58. DIAGNOSIS
• Specimens : Bronchial secretion, urine, Scrapings from infection, Sputum,
Skin Scrapings, Bone marrow, Pleural fluid , Blood and cerebrospinal fluid.
• Microscopic Examination :
- 10% KOH and Parker ink or calcofluor white mounts.(Skin, Body
fluids).
- Positive direct microscopy demonstrating spherules with endospores.
• Culture : On Blood or Sabouraud agar must be incubated for several
weeks.
• Treatment :
- Amphotericin B
- Anoralazole derivative may be used
59.
60. 3. HISTOPLASMOSIS
• Caused by : Histoplasma capsulatum (Dimorphic fungus).
• Natural habitat : Soil .
• Grow as a filamentous form in culture.
• In human tissues it forms : Yeast cells.
• Inhalation of Spores ( Conidial ) into the respiratory tract.
• It affects the reticulo-endothelial system(RES).
• Observed commonly in AIDS patients.
61. DIAGNOSIS
• Specimens : Bronchial secretion, urine, Scrapings from infection, Sputum,
Skin Scrapings, Bone marrow, Pleural fluid , Blood and cerebrospinal fluid.
• Microscopic Examination :
- 10% KOH and Parker ink or calcofluor white mounts.(Skin, Bodyfluids).
- Positive direct microscopy demonstrating characteristics yeast-like
cells.
• Culture : On Blood or Sabouraud agar must be incubated for several
weeks.
• Treatment :
- Amphotericin B
62.
63. 4.
PARACOCCIDIOIDOMYCOSIS
• Caused by Paracoccidioidies brasiliensis (Dimorphic fungus).
• Inhalation of Spores.
• Natural habitat : soil.
• Primary : Chronic granulomatous infection are found in the lung
• Occasionally infect Gastro intestinal mucosa.
• The fungus can disseminate hematogenously or
lymphogenously into the skin, mucosa or lymphoid organs.
64.
65. DIAGNOSIS
• Specimens : Bronchial secretion, urine, Scrapings from infection, Sputum,
Skin Scrapings, Bone marrow, Pleural fluid , Blood and cerebrospinal fluid.
• Microscopic Examination :
- 10% KOH and Parker ink or calcofluor white mounts.(Skin, Body
fluids).
- Positive direct microscopy demonstrating 20-60 um , round, narrow
base
budding yeast cells with multiple budding.
• Culture : On Blood or Sabouraud agar must be incubated for several
weeks.
• Treatment :
- Amphotericin-B
- Itraconazole
66.
67. OPPORTUNISTIC MYCOSIS
1. CANDIDIASIS
• 70% of all human Candida infections are caused by Candida
albicans.
• The rest by : C. parapsilosis , C. tropicalis, C. kruzei.
• Candida is a normal inhabitant of human and animal mucosa.
• Candidiasis usually develop in person whose immunity is
compromised.
• The mucosa is affected most often.
• Skin is mainly infected on the moist, warm parts of the body.
• Secondary infections of the lungs , kidneys and other organs.
68.
69. DIAGNOSIS
• Specimens : Bronchial secretion, urine, Scrapings from infection, Sputum,
Skin Scrapings, Bone marrow, Pleural fluid , Blood and cerebrospinal fluid.
• Microscopic Examination :
- 10% KOH and Parker ink or calcofluor white mounts.(Skin, Body
fluids).
- Grocott’s methenamine silver(GMS) or Gram stain (Tissue sections).
• Culture : On Blood or Sabouraud agar must be incubated for several
weeks.
- After 48 hours of incubation on agar mediums, round, whitish,
rough
surfaced colonies form.
• Treatmet : Topical – Nystatin and Azoles
- Amphotericin B with 5- fluorocytosine
70.
71. 2. ASPPERGILLOSIS
• Aspergilloses are most frequently Caused by Aspergillus
fumigatus, A. flavus , A. niger.
• By inhalation of Spores or Ingestion of products contaminated
with Aspergillus.
• Pathway of entry : Bronchial system , but the organism can also
invade the body through injuries in the skin or mucosa.
• Aspergillosis of respiratory tract is common.
• Cerebral Aspergillosis
72. DIAGNOSIS
• Samples Collection : Sputum, Bronchial washings and Tracheal aspirates
• Microscopical Examination :
- Sputum, washings and aspirates make wet mounts in 10%
KOH and Parker ink or Gram stained smears.
- Tissue sections should be stained with H&E ,GMS.
• Culture : Sabouraud Dextrose agar
• Treatment :
- High dose of Amphotericin B
- Azoles
73. 3.CRYPTOCOCCOSIS
• Caused by Cryptococcus neoformans (Encapsulated Yeast).
• The individual cell is surrounded by a polysaccharide capsule
several micrometers wide.
• Normal habitat : Soil . Frequently found in bird droppings.
• The organisms are inhaled and enter the lungs , resulting in a
pulmonary cryptococcosis
• Pathogen can reach to Brain(CNS) and can cause Cryptococcal
Meningitis.
• Commonly found in immuno compromised patients. Ex – AIDS.
77. Questions
Ques 1- Which of following organisum is not been isolated artificial culture media?
a) Crytococcus neoformans
b) Rhinospordium seeberi
c) Histoplasma capsulatum
d) Penicillium marneffi
Ques 2 – Which of the following added in SDA to suppress the growth of saprophytic fungi?
a) Cycloheximide b) Chloromphenicol c) Gentamicin
d ) Amhotericin B
Ques 3 - Which of the following statements is not true for DERMATOPHYTE?
a) The fungi affect the keratinised layer of skin
b) They affect the hair and nail
c) They may be geophilic
d) They do not grow at room temperature
78. Ques 4- The following are saprophytic fungi associated with infection in
immunocompromised individual except
a) Candida albicans
b) Aspergillus fumigatus
c)Cocciodes immitis
d) Rhizopu Arrhizus
Ques 5- Fungal agent that does not infect nail-
a) Trichophyton b) Epidermophyton
c) Microsporum d) Candida albicans
Ques 6- Fungi which do not have Sexual stage-
a) Zygomycota b) Ascomycota
. c) Basidiomycota d) Fungi imperfecti
79. Short Answer Questions-
Ques 7- Write a short note on Dermatophytoses.
Ques 8- What are Dimorphic fungi? Explain with an Example.
Long Answer Questions-
Ques 9- Discuss the Clinical Manifestations and Laboratory diagnosis of
Sporotrichosis.
