This document discusses systemic mycoses, specifically histoplasmosis and cutaneous mycoses. It provides details on: - Histoplasmosis, caused by the dimorphic fungus Histoplasma capsulatum, which can cause acute or chronic pulmonary infection or disseminated infection. It is commonly found in the Americas. - Cutaneous mycoses (ringworm), caused by dermatophytic fungi of the genera Trichophyton, Microsporum, and Epidermophyton. These fungi infect skin, hair, and nails. Diagnosis involves microscopic examination of skin/hair samples and culture. - Laboratory diagnosis and treatment of both conditions with antifungal drugs like amp

1. MEDICAL MICROBIOLOGY:
Topic:systemic
mycoses-
histoplasmosis ,
cutaneous mycoses
Submitted by :
R.priyanka , 2nd
msc microbiology

2. SYSTEMIC MYCOSES:
 Systemic mycoses are deep mycotic infections .It causes
infection in inner parts of the body .
eg. Lungs , blood etc.,
 Inhalation of air borne spores produced by casual moulds
 Present as saprophytes in soil and on plant material
 There are caused by dimorphic fungi occurs mainly in
american continent
 Two types :
 Primary mycoses
 Opportunistic mycoses

3. Histoplasmosis
 General characteristics:
 Histoplasmosis is the most prevalent pulmonary mycoses
of humans and animals
 Infection is initiated by inhalation of the fungal conidia
 Dr.samuel Darling discovered histoplasmosis .This disease
is also called the ‘Darling’s disease’
 Two colonial forms are produced during cultivation . They
are typeAor albinotype and typeB or the brown type
 Both phenotypes produce identical yeasts and tissues
forms

4. Histoplasmosis:

5.  H.capsulatum is a facultative intracellular parasite .
 H. capsulatum is an antigen extracted from H.
capsulatum
Pathogenesis:
 The aetiological agent enters into the lungs through
inhalation
 Conidia develops into yeasts after settling of
H.capsulatum mycelium in the alveoli
 Yeast cells are engulfed by alveolar macrophage
 Within macrophage , yeast cells are able to multiply
and are disseminated to the reticuloendothelial tissues
such as liver , spleen, bonemarrow, and lymph nodes
through blood stream

6.  Tissue reaction may involve an early infiltration of
neutrophils and lymphocytes
Three types:
 Acute pulmonary histoplasmosis:
 Symptoms range from a mild flu like illness that clears
spontaneously to a moderate or severe diseases
 Incubation period varies from one to several weeks
 Symptoms are fever, cough ,chest pain , dsypnea, hoarseness,
night sweats and weight loss.
 Chronic pulmonary histoplasmosis:
 It is the most often seen in males. It is considered to be an
oppurtunistic complication of lung disease
 Symptoms are low grade fever, a productive cough ,
progressive weakness, and fatigue

7.  Disseminated histoplasmosis:
 Dissemination may be completely benign and in apparent
except for the calcified lesions usually in the organs of
reticuloendothelial tissues
 It may be acute and progressive
 Symptoms are splenomegaly , hepatomegaly , weight loss,
anaemia, and leucopenia
Laboratory diagnosis:
specimen:
blood [ buffycoat]
bonemarrow
sputum
scraping from the superficial lesions
Pus from the sinustract

8.  Pathogenesis:
Acute pulmonary
histoplasmosis
Chronic
pulmonary
histoplasmosis
Disseminated
histoplasmosis

9. microscopy:
smears of infected specimen fixed with methanol and
stained with wright or giemsa stain will reveal
characteristicsally ellipsoidal yeast cells inside the
macrophage
culture:
in endemic area, specimen should be inoculated at least
four media which are
sabouraud’s with antibiotics incubated at 25-30 ̊c
brain heart infusion agar with 5%sheep blood without
antibiotics incubated at37 ̊c
brain heart infusion agar with 5% sheep blood with
antibiotics cycloheximide incubated at 25- 30 ̊c
 PH of the media should be neutral , incubated at least for 4
weeks because the etiological agent grows very slowly

10.  Skin test:
histoplasmin skin test is a valuable tool in epidemiology .
Within two weeks after infection , most persons test positive
Serology:
two tests are widely used for diagnosis. They are
complement fixation test and immunodiffusion test
Treatment:
amphotericin B is the drug of choice . A total of 1.5g is
recommended

11. Cutaneous mycoses:
 General characters:
 “ ringworm “ diseases of the nails , hairs , and or
stratum corneum of the skin caused by a group of
keratinophilic fungi called dermatophytes
 40 species in the genera trichophyton, microsporum,
epidermophyton
 Causative agent of ringworm varies case to case
 Natural reserviors – humans , animals and soil
(anthrophilic, zoophilic, and geophilic)
 Infection faciliated by moisture , warmth, specific skin
chemistry

12. Cutaneous mycoses:

13.  Long infection period followed by localized inflammation
and allergic reaction to fungal proteins
 Dermatophytosis = tinea = ringworm
Pathogenesis:
dermatophytosis
classification: three groups types
clinical
etiological
ecological

14.  Clinical:
tinea corporis:
small lesions occuring anywhere on the body
Tinea pedis:
 Athlete foot , infection of toe webs and soles of feet
Tinea ungulum :
 Nails , clipped and used for culture
Tinea capitis:
 Head frequently found in children
Tinea barbae:
 Ringworm of the bearded areas of the face and neck

15. Tinea
corporis Tinea
pedis
Tinea ungulum
Tinea
capitis
Tinea barbae
Clinical:

16. Etiology [ 3 genera ]:
trichophyton
microsporum
epidermophyton
Trichophyton:
 Infection on skin , hair, and nails
- ectothrix: more or less parallel rows of anthrospores
produced on the surface
- endothrix: growth inside hair shaft only
eg : black dot , flavus hair
 species are Trichophyton ruburum
Microsporum:
infection on skin and hair [ not cause of tinea ungulum]
 species are Microsporum canis

17.  Epidermophyton :
 Infection on skin and hairs [ not cause tinea capitis ]
 Species are Epidermophyton floccosum
Ecology:
 To determine the source of infection :
anthrophilic
zoophilic
geophilic
Anthrophilic :
 Associated with human only , person to person
transmission through contaminated objects [ comb , hat
etc]
 Eg , M.audonil , T. tonsurans

18.  Zoophilic:
 Associated with animals . Direct transmission to humans by
close contact with animals
 Eg, M.canis , T. verrucosum
Geophilic :
 Usually found in soil [ soil saprophytes ] transmitted to
humans by direct exposure
 eg, M.gypseum , T. ajelloi
Laboratory diagnosis:
 Clinical:
appearance
wood’s lamp[ uv ,365nm]
Lab:
A. direct microscopic examination [10-25%koH]
B. Culture.

19. mycobiotic agar
sabouraud dextrose agar
selective media – containing cycloheximide and
chlorampenicpol
 Incubate at 25 ̊c
 Identification based on the conidia
Treatment :
 Therapy consists of through removal of infected and dead
epithelial structure and application of a topical anti- fungal
chemical or antibiotic
 Treatment of dermatophytes includes topical antifungal
agents
 Tolnaftate , micronazole applied for several weeks