Morphology, Pathogenesis, Lab Diagnosis and Treatment - Candida albicans

1. Dr. S. MEENATCHISUNDARAM
ASSOCIATE PROFESSOR
DEPARTMENT OF MICROBIOLOGY
SNMV COLLEGE OF ARTS AND SCIENCE
COIMBATORE
https://orcid.org/0000-0002-8691-449X
95496
https://scholar.google.com/citations?user=IkdZ5XsAAAAJ&hl=en
MYCOLOGY – CANDIDA ALBICANS

2. INTRODUCTION
 Candidiasis (candidiasis, moniliasis) is an infection of the skin, mucosa, and rarely of the
internal organs, caused by a yeast-like fungus Candida albicans, and occasionally by other
Candida species.
 Several species of the yeast genus Candida are capable of causing candidiasis.
 They are members of the normal flora of the skin, mucous membranes, and
gastrointestinal tract.

3. Candida albicans
 Family: Sachharomycetaceae
 Phylum: Ascomycota
 Approximately 200 species
 About 20 associated with pathology in humans and animals

4. Candida albicans
 Ubiquitous yeast
 Found on many plants
 Normal flora of GI tract of mammals and mucocutaneous membranes of humans
 Present in all areas of human GI tract
 Common species in GI tract
 C. albicans
 C. tropicalis
 Candida parapsilosis
 C. glabrata

5. Candida albicans
 Polymorphic yeast, i.e., yeast cells, hyphae and pseudo hyphae are produced
 Ability to assume various forms may be related to the pathogenicity
 Yeast form:
 10-12 microns in diameter
 gram positive
 grows overnight on most bacterial and fungal media
 pseudo hyphae may be formed from budding yeast cells that remain
attached to each other.
 Spores may be formed on the pseudo mycelium, called chlamydospores
and can be used to identify different species of Candida.
MORPHOLOGY

6. Candida albicans
MORPHOLOGY
Candida albicans:
yeast form and pseudohyphae
Gram stained smear of Candida albicans

8. Candida albicans
 Disease: Candidiasis
 Clinical manifestations may be acute, sub acute, chronic or episodic
 Can cause various forms of infections, ranging from superficial manifestations
involving skin, nails and mucosal surfaces, to deep seated infections involving
various internal organs to disseminated disease
 Diseases subdivided into 2 large groups:
Mucocutaneous candidiasis
Deep seated candidiasis
Clinical significance

9. Candida albicans
3 Forms
 Cutaneous infections
 Nail infections
 Mucosal infections
Mucocutaneous candidiasis

10. Candida albicans
Candidal intertrigo (lntertriginous candidiasis)
 Most common form
 Organisms colonize skin folds, particularly in moist and macerated sites (axilla, groin,
inter and sub, mammary folds, umbilicus)
 Form erythematous lesions with vesicles
 (elevation of skin with clear fluid) and pustules
 (elevation of skin with purulent fluid) in combination with pruritis (severe itching)
Cutaneous candidiasis
Intertrigo (intertriginous dermatitis) is an inflammatory condition of skin folds,
induced by heat, moisture and lack of air circulation. Intertrigo frequently is worsened
by infection, which most commonly is with Candida.

11. Candida albicans
Erosio interdigitalis
 Skin folds between the fingers become macerated (having undergone reddening, loss
of skin) and itchy
 Associated with excessive exposure to moisture
 Common in dishwashers, barlenders, fruit cannery workers
Perianal rash (Diaper candidiasis)
 Involves infants wearing nappies
 Rashes seen in perianal area
 Infection may be secondary to pre-existing inflammatory condition

12. Candida albicans
Chronic mucocutaneous candidiasis
 Relatively rare condition
 Most severe clinical form of superficial candidiasis
 Cause: C. albicans
 Characterised by the presence of persistent lesions, with high rate of recurrence,
starting in early childhood and persisting throughout the individual's lifetime
 Lesions at various skin site, not limited to skin folds
 Warty lesions termed as candida granuloma

13. Candida albicans
 Agent: C. albicans (major), C. parapsilosis,
C. guilliermondii
 Characterised by prominent swelling, redness, pain
 Paronychia: infection of nail folds (fold of skin
supporting nail at its base)
 Onychia: infection of nails
Affected nails become discoloured, eroded, brittle,
detached from nail bed and painful
Nail infections (Paronychia and Onychia)

14. Candida albicans
 Most frequent
 Major agent: C. albicans
 Others: C. glabrata, C. guilliermondii, C. parapsilosis,
C. tropicalis
 Several different clinical forms
 Acute pseudomembranous candidiasis (oral thrush)
 Acute atrophic candidiasis
 Chronic atrophic candidiasis
 Chronic hyperplastic candidiasis
 Angular cheilitis
Oral candidiasis

15. Candida albicans
 Characterised by white-grey lesions on the gums,
tongue, or oral mucosa, can appear as single lesion or as
confluent large plaques
 Lesions covering large area may be painful and disturb
food intake
 May spread to the oesophageal mucosa, and cause
dysphagia
 Generally occurs in AIDS patient, cancer patient,
debilitated individuals, elderly people and in infants of
the mothers with vaginal candidiasis
Oral thrush

16. Acute atrophic candidiasis
 Characterised by painful, erythematous mucosa,
particularly on the tongue
 May cause loss of tongue papillae, affecting food
intake.
Chronic atrophic candidiasis
 Known as denture stomatitis
 Occur in elder individuals wearing dentures
 Characterised by erythema and/or oedema of the
mucosa under the dentures. (denture is a removable
replacement for missing teeth and surrounding
tissues)
 Not painful
Candida albicans
Acute atrophic candidiasis
Chronic atrophic candidiasis

17. Chronic hyperplastic candidiasis
 Also known as candida leucoplakia
 Rarer condition
 Characterised by white plaques, can appear on
various sites of oral mucosa
 Can't be removed like pseudomembranous form
 May transform into a malignant state
Angular cheilitis
 Characterised by erythema and fissures at the
folds of the corners of the mouth
 May be associated with denture stomatitis or
oral thrush
Candida albicans
Chronic hyperplastic candidiasis
Angular cheilitis

18. Vaginal candidiasis
 Common infection in females of reproductive age group, primarily during the fecundly period
 Prevalence : 5 – 20%
 Prevalence increases in particular groups like pregnant or diabetic women, using oral
contraceptives (hormonal effect) and after antibiotic treatment
 Cause: C. albicans, C. glabrata, C. tropicalis
 important feature: recurrence of infection
 Transmission: sexual transmission to male partners
Syndrome
 Complaints of vulvovaginal pruritis and discharge (thick curd like or thin)
 Erythema of the vulvovaginal mucosa and also of perianal area
 Lesions on the mucosal surface are basically adherent plaques
 May cause pain and discomfort during sexual intercourse
Candida albicans

19. Deep seated candidiasis
 Infection of visceral organs and: possibly to multiple organs or disseminated disease
 includes
Candidiasis of GI tract
Candidiasis of respiratory system
Candidiasis of CNS
Candidiasis of renal and urinary system
Candidiasis of cardio vascular system
Hematogenous disseminated disease
Ocular infection and a variety of other specific manifestations
Candida albicans

20. Candidiasis of GI tract Oesophagitis
 Painful dysphagia (Difficulty swallowing (dysphagia) means it takes
more time and effort to move food or liquid from your mouth to your
stomach) and chest pain
 White patches on oesophageal mucosa as in oral candidiasis
 May be associated with oral candidiasis
 10 – 30 % of All DS patients with oral candidiasis may also have
candida
Candidiasis of GI tract
 Though being normal flora of GI tract, clinical involvement of mucosal
surfaces of the stomach and/or intestine with mucosal white plaques
and ulcerations are found
 Plays an important role in the pathogenesis of disseminated
candidiasis
Candida albicans
Candida esophagitis
Esophagitis, also spelled oesophagitis, is a disease characterized by inflammation of the esophagus.
It connects the pharynx to the stomach; swallowed food and liquids normally pass through it.

21. Candidiasis of respiratory system
 Involves lungs
 Bronchopneumonia originates from hematogenous spread of the fungus as a part of a
disseminated infection or from introduction of pathogen into the lungs
CNS Candidiasis
 Risk group- AIIDS patients and pre-term infants
 Seen as part of disseminated candidiasis, involving meninges, abscess formation in brain tissues
Candida albicans

22. Endocarditis
 Primarily seen in IV drug users and in individuals with impaired heart valves
 Also may occur in patients after cardiac surgery procedures or as a sequelae of
anticancer therapy
Candida albicans

23. Urinary Tract Infections
 Urinary tract infections are ascending or hematogenous
 Infection of the urinary tract via the hematogenous or ascending routes may produce
cystitis, pyelonephritis, abscesses, or expanding fungus ball lesions in the renal pelvis.
 The clinical findings in disseminated infections of the kidneys, brain, and heart are
generally not sufficiently characteristic to suggest C. albicans over the bacterial pathogens,
which more commonly produce infection of deep organs.
Candida albicans

24. Eye Infections
Endophthalmitis appears as white cotton on retina
 Candida endophthalmitis has the characteristic funduscopic appearance of a white
cotton ball expanding on the retina or floating free in the vitreous humor.
 Endophthalmitis and infections of other eye structures can lead to blindness.
Candida albicans

25. A. Specimens:
 Specimens include swabs and scrapings from superficial lesions, blood, spinal fluid,
tissue biopsies, urine, exudates, and material from removed intravenous catheters.
B. Direct microscopy:
 Tissue biopsies, centrifuged spinal fluid, and other specimens may be examined in Gram-
stained smears for pseudohyphae and budding cells.
 Wet films or Gram-stained smears from lesions or exudates show budding gram-positive
cells.
 As Candida can be seen on normal skin or mucosa as well, only its abundant presence is
of significance.
 Demonstration of mycelial forms indicates colonization and tissue invasion.
Candida albicans

26. C. Culture
Cultures are obtained on Sabouraud’s dextrose agar (SDA) and on ordinary
bacteriological culture media, e.g. blood agar at room temperature or at 37°C. Colonies
are creamy white, smooth and with a yeasty odor. Gram-stained smear from colonies
shows gram-positive budding yeast cells
Candida albicans

27. D. Identification:
The following tests are done to differentiate C. albicans from other species.
i. Germ tube test:
C. albicans has an ability to form germ tubes within two hours when incubated in
human serum at 37°C (Reynolds Braudephenomenon)
Candida albicans

28. D. Identification:
ii. Chlamydospores:
Chlamydospores develop in a nutritionally deficient medium, such as cornmeal agar at
20°C. They can be seen at the end of pseudohyphae.
iii. Carbohydrate fermentation and carbohydrate assimilation tests.These are
used in identification of C. albicans and other species of Candida.
Candida albicans
Candida albicans - Chlamydospores

29. E. Serology:
The detection of circulating cell wall mannan, using a latex agglutination test or an
enzyme immunoassay, is much more specific.
F. Skin test:
Delayed hypersensitivity to Candida is so universal that skin testing with Candida
extracts is used as an indicator of the functional integrity of cell-mediated immunity.
Candida albicans

30.  Commonly treated with antimycotics; include topical clotrimazole, topical nystatin,
fluconazole, and topical ketoconazole
 Amphotericin B, 5-fluorocytosine and clotrimazole may be used for disseminated
candidosis.
TREATMENT