2. Prepared by Dr. Jamal Bayed
Salim, Ph.D Microbiology and
Immunology, University of
Kassala, faculty of medicine and
health sciences.

3. Mycology-1
Is study of fungi and the
diseases they cause .
Structure & growth of fungi
Fungi are eukaryotes and
differ from bacteria in that :

4. 1. Their cell wall contain
chitin which is not sensitive
to antibiotics .
2. The fungal cell
membrane contain
ergosterol on which
antifungal drugs act .

5. There are two types of
fungi
1. Yeasts : grow as
single cell and reproduce
by budding .
2. Molds: grow as long
hyphae

6. that can be septate or
non septate , and Form
Mycelium .

7. some are dimorphic i.e
at 26˚C they exist as
molds and at 37˚C they
occur as yeast

8. Fungi are aerobes , that
exist in the environment .
some fungi reproduce
sexually forming sexual
spores : Zygosporese ,
ascospores and
basidospores .

9. some fungi form asexual
spores (candida) e.g:
arthospores ,
chlamidospores
blastospores ,
spongiospores .

10. pathogenesis of fungal
disease :
fungi can cause :
1. superficial infections .
2. subcutaneous infection .
3. Deep systemic infection .

11. The pathogenesis by one of
3 ways :
1. Mycotic infection and
granuloma formation .
2. Mycotoxicosis : caused
by ingested toxins .
 3. Allergies to fungal
spores .

12. antigens stimulated
immune Response to
form granuloma .

13. The serious infections
are associated with low
cell mediated immune
response .

14. Lab rotary Diagnosis :
General approach :
Specimen : depends on the
infected site :
skin scraping
Nail clipping
Hair

15. oral swabs
vaginal swabs
Grains
sputum , or bronchial
lavage
Tissues

16. 1. Microscopically
examination : directly
after staining .
2. Culture of organism
on sabouraud ‘s media .

17. 3. serological tests .
4. DNA probe tests .

18. Important fungal disease
Type of
infection
Disease Organisms
1. Cutaneous Tinea versicolor Malassezia
Dermatophytosis
(ring worm)
Microsporum
Tricophyton
Epidermophton

19. 2. Subcutaneous Mycetoma Many fungi
& bacteria
3. Systemic Histoplasmosis Histoplasma
4. Opportunistic Candidiasis
Aspergillosis
Cryptococcosis
Candida
Aspergillus
Cryptococcus

22. INTRODUCTION
It is superficial
infection of skin and
keratin associated
tissue i.e. hair and
nail,

23. by a group of
fungi know as
Dermatophyte.

24. They are filamentous
fungi .these three
structures due to their
keratin content, they are
keratinophilic
&keratinlytic

25. And keratinases
that breakdown
keratin for their
growth.

26. Dermatophytosis
is one of the most
prevalent disease.
It is not life
threatening

27. or deblitating
and there is no
systemic
involvement.

28. It is
infectious
and can occur
in epidemics.

29. Classification
There are three big genera
of dermatophytes:
1. Microsprum 17 spp →
2. Trichophyton 21 spp →

30. 3. Epidermophyton
2 spp.
They all belong to
the deutromycetes

31. Microsporum spp.
The most important
are:
M.canis, M.audouinii,
M.gypseum.

32. Trichophyton spp:
T.mentagrophyt
es, T.rubrum,
T.violacium

33. T.tonsurans,
 T.verrucosum,
T.schoenlini,
T.soudanenses.

34. Epidermophyton
sp:
Only one
important
E.floccosum

35. There are some
clinical and
mycological
differences:
Clinically:
1. site of infection

36. Microsporum:
infects skin and hair
but not nails.
Trichophyton: infect
skin hair and nails.

37. Epidermophyton:
infects skin and nail
but not hair.
2. UV light from
wood’s lamb on the
lesion:

38. In M.canis and in 16%
of M.audovnii they
florescent, green –apple
colour.
T.schonledoes doesn’t
florescent but gives a
reddish colour.

39. Mycological
Differences:
This depend on the
production of Macro
and Microcondia and
the presence of other
special structures:

40. EPIDEMIOLOGY
Dermatophytosis ,
(dermatomycosis), is
a cosmopolitan
disease and can occur
in epidemics.

41. Its prevalence depends
on the climate and
habits of the people .
It is more in hot climate
with high humidity.

42. It’s mostly a
diseases of poor
societies with
overcrowding ,
malnutrition and
immunosupprestion
.

43. The lesions is
known as Tinea or
ring worm , because
it’s round scaly ,
painless and may be
itchy.

44. It’s named according
the site of infection e.g.
T.capatis : in skull eye
borows and lashes
T. manus : in hands and
in inter cleft

45. T.barbae: in beared and
moustage
T.ungium: in nails
onconychomycosis
T.pedis : in foot ( Athlete
foot)

46. T.crusis: in groin and
and external genitalia
and can be STD.
Any age group can be
infected , but infection

47. of the scalp is the
more common in
children than adults .
On the other hand
skin and nail
infections are
commoner in adults .

48. Male: Female ratio =
3:1.
Sources of infection are
man , animal and soil.
Man: anthropophilic
fungi e.g. M.audounii
and T.schoenleinii.

49. Animal: zoonotic
infection from zoophilic
fungi e.g. M.canis from
cats and doges,
T.verocosum from
cattle.

50. Soil:
saprophytic or
geophilic e.g
M.gypseum.

51. MODE OF SPREAD:
Incidence is increased
by over crowding ,
Malnutrition and
trauma.

52. In T.capatis, hair combs
, head cops and barber
clippers sharing.
In T.corporis spores are
Transmitted through
under wears .

53. In T.pedis spores are
shared in common
bathes or by wearing
occlusive shoes.
Infections caused by the
another anthrophylic
fungi

54. are usually mild but tend
to be chronic , dry
and scaly , do not
respond well to
treatment and re cure
after treatment.

55. Where as zoophilic
infections are aggressive
, extensive with more
inflammatory reaction,
but better response to
treatment and no
recurrence.

56. PATHOGENESIS:
In scalp:
Spores germinate in the
stratum and they grow
in the hair Follicle to
produce keratinase that

57. renders the Hair
fragile and
easly breaks
leaving an area
of alopicia.

58. When spores lie
between the hair
sheath and shaft it is
called ectothrix .
spores as it is the
case in microsporum
spp .

59. Endothrix spores when
they grow inside the
hair shaft e.g. some spp
Of Trichophyton
In T. schoenleinii there
are no ecto or endothrix

60. spores but only
hyphae grow
inside hair shaft ,
sometimes with
arthrospores.

61. CLINICAL FEATURES:
Tenia capatis:-
more in children and can
spread in an epidemic form
 It is not a debilitating or
life – threatening condition.

62. there is destruction to
hair follicle and
accumulate of
arthrospores and dead
tissue depris at the
opening of the hair
follicle

63. known as scatulum ,
when removed an
oozing surface and area
of alopecia , this
condition is known as
favus.

64. It starts during
Childhood and tend to
continue in adult life if
not treated and may
lead to permanent
alopecia .

65. A solitary lesion with
loss of hair and
inflammatory reaction
+pus is called Kerion
, caused by M.canis
and T.verecosum

66. it responds
well to
treatment and
does not recur.

67. In T.capatis Multiple
lesions may occur and
extend down to the
neck and reach the
external ear canal and
cause otomychosis.

68. In Tinea Manus :
usually starts in the
moist inter digital
spaces which
become macerated.

69. It’s more common in
people who immerse
their hands in water for
long periods.
Tinea pedis or Athelete
foot due to moisture

70. And usually between the
4th and 5th for it can be
in a form of dry fissure
or wet when it is moist
soggy with white

71. macerated skin and
spread to inter or
subdigital spaces and to
the sole of the foot .
T.pedis is chronic ,
difficult to treat and
recurs the treatment.

72. Tinea unguium
(onychomycosis)
infection starts in the
outer surface of the nail
which becomes irregular
, thickened and fragile ,
then to nail bed

73. and multiply where
depris of epithelial cells,
hyphae and spores
accumulate in very
severe chronic condition

74. The fungal Antigens
cause allergy in a form
 of vesicular eruption . ,
mostly in the
palms , and usually
bilateral

75. and symmetrical with no
fungal element in it, It is
called the
dermatophytid or
“Íd”reaction.

76. DIAGNOSIS:
Clinically:
history and examination by
wood’s light. site.
LABORATORY DIGNOSIS:
Speciment: skin scraping,

77. scalp scraping or nail
clipping.

78. Method: disinfect the
area with 70% alcohol,
use sterile gauzes and
not cotton wool .
Then with a blunt
scalped scrape and take
broken hair by a forceps.

79. Scrap the depris under
the nail .
keep on a clean sheet of
paper and fold it and
make a label for it:
name, Age, Date, Site .

80. Direct microscopy:
 on a clean slide put part
of specimen and add
20% KOH ,cover glass
avoiding air bubblers,

81. then pass through
flame three times
to enhance
dissolution of
keratin by KOH,

82. then leave at 37˚c
for half and hour
and put under the
microscope x10-
x40-x100 .

83. What do you see?
 In skin scrapings:
epithelial cells and
 segmented hyphae
and some times
arthropores.

84. The presence of
the hyphae and
arthrospores is
diagnosis.

85. Nail: epithelial cells of
nail are flattened.
Hair: Endo-or
ectothrix spore+
hyhpae + epithelial
cells.

86. CULTURE:
 Dermatophytes grow on
sabouraud’s agar+
 cycloheximide to
suppress other
 contaminant fungi +

87. chlorophenicol
 “to suppress bacteria
“ At 26˚c and
37˚c until growth is
seen To differentiate
by:-

88. Rate of the grouth :
 Most are slow
growers; M.canis 5 –
7 days;
 T. violaceium 3
weeks.

89. 2. Configuration “
colonial morphology:
rough, smooth,
powdery etc . …

90. 3. Pigments Production:
T.rubrum:
 red- pink, Diffuse.
T.violacium:
 a violet, localized.

91. T.schoenlinii and T.
soudanense produce
yellow pigments that
diffuse all over the
medium , more in the
periphery than the
center .

92. 4. Needle-mount:
To see the organism
as it is growing after
staining with lacto
phenol cotton blue (
L.PCB) .

93. Note the presence
of Macro and
Microconidia and
other special
structures.

94. TREATMENT:
Topical antifungal or
without systemic agents.
Imidazole derivatives :
Clotrimazole, Econozole ,
Bitanozole ,Ketoconazole.

95. Turbinatin (lamisil)
These are applied
(tow weeks after
clinical cure to
ovoid recurrence.

96. In cases of T.capatis,
T.ungium, recurrence
or chronic infection
A systemic antifungal
is added:

97. 1. Griseofulvin tabs:
 1gr daily after a
fatty meal, Its
abroad spectrum
antifungal

98. epithelial cells ,thus it is
given until replacement
of skin is complete .
S: headache and
abdominal upset.

99. 2.Ketoconazole(Nezoral)
tabs:
 1tab (200mg) once daily.
 In cases of skin
infection usually2weeks
of treatment are enough

100. In scalp : 4 – 6
weeks.
In nail : 6 month –
1gr. (especially. If toe
nail)………………………
……….

122. Microconidia(T.rubrum)

123. Macroconidia of Trich.