1. Candidiasis
A primary or secondary mycotic infection caused by members of the genus Candida. The clinical manifestations may be acute, subacute or chronic to episodic. Involvement may be localized to the mouth, throat, skin, scalp, vagina, fingers, nails, bronchi, lungs, or the gastrointestinal tract, or become systemic as in septicaemia, endocarditis and meningitis.
Distribution: World-wide.
Text slide.

2. Candida
MOST COMMON invasive fungal infection in immunocompromised patients
4th most common cause of nosocomial blood stream infection
Species implicated in human disease most often:
C. albicans
C. tropicalis
C. parapsilosis
C. krusei (fluconazole resistant)
C. glabrata
C. lusitaniae (amphotericin B resistant)

3. Thick cell wall of mannan and glucan polysaccharides
Candida
Thick cell wall of mannan and glucan polysaccharides
Unicellular, budding (asexual) reproduction (blastospores)
Filament formation
Pseudohyphae (buds stay attached, constricted, chains of elongated blastospores)
Hyphae (buds germinate)

4. Cell wall Candida albicans

5. Candida Human commensal (endogenous) Environmental (exogenous)
skin, gastrointestinal, genitourinary tracts
5 - 15% carriage rate in normal people
increased carriage with use of antibiotics
Environmental (exogenous)
much less common
food, animals, soil hospital environment
outbreaks have occurred

6. Candida - Clinical Children with T-cell abnormality
Mucous membrane infections
Thrush (oropharyngeal)
Esophagitis
Vaginitis
Cutaneous infections
Paronychia (skin around nail bed)
Onychomycosis (nails)
Diaper rash
Balanitis
Chronic mucotaneous candidiasis
Children with T-cell abnormality

7. Candida - Clinical Urinary tract infection
Fungemia
Disseminated (systemic, invasive) infection
Immunocompromised patients
Cancer/chemotherapy
Neonatal candidiasis
Endophthalmitis (eye)
Liver and spleen
Kidneys
Skin
Brain
Lungs
Bone

8. Mucosal candidiasis
Oral thrush
Vaginal candidiasis

9. Cutaneous candidiasis
Diaper dermatitis
Balanitis

10. Cutaneous candidiasis
Onychomycosis and paronychia
Chronic mucocutaneous candidiasis

11. 056. Oral candidiasis in an infant showing characteristic patches of a creamy-white to grey pseudomembrane composed of blastoconidia and pseudohyphae of C. albicans. Note the mouth of normal newborn infants has a low pH which may promote the proliferation of C. albicans. The infections are usually acquired during the birth process from mothers who had vaginal thrush during pregnancy. Clinical symptoms may persist until a balanced oral flora has been established.
056

12. 057. Chronic oral candidiasis of the tongue and mouth corners (angular cheilitis) in an adult with an underlying immune deficiency. Note characteristic white pseudomembrane composed of cells and pseudohyphae of C. albicans.
057

13. 058. Angular cheilitis an intertrigo and fissuring caused by maceration of the corners of the mouth is frequently complicated by chronic infection with C. albicans. Note the white pseudomembrane-like colonies in the mouth corners of this adult patient. (Courtesy Dr G. Hunter, Adelaide, S.A.).
058

14. 059. Solar cheilitis in a young boy showing colonization of the lip by C. albicans. (Courtesy Dr G. Hunter, Adelaide, S.A.).
059

15. 060. Candida granuloma of the forehead and angular cheilitis of the mouth in a young girl with chronic mucocutaneous candidiasis. Note thick crusted lesions of the scalp and forehead. C. albicans was isolated.
060

16. 061. Interdigital candidiasis of the hands may develop particularly in persons whose hands are subject to continuing wetting, especially with sugar solutions or contact with flour. C. albicans was isolated. (Courtesy Dr G. Hunter, Adelaide S.A.).
061

17. 062. Interdigital candidiasis of the feet explains l% of cases of "athletes foot" and must be distinguished from tinea pedis caused by dermatophytes. C. albicans was isolated. Compare this slide with slide 251 showing T. rubrum infection of foot. (Courtesy Dr G. Hunter, Adelaide, S.A.).
062

18. 063. Intertriginous or flexural candidiasis of the groin may also mimic tinea cruris caused by a dermatophyte. Note erythematous scaling lesions with distinctive border and several small satellite lesions. C. albicans was isolated. (Courtesy Dr D. Hill, Adelaide, S.A.).
063

19. 064. Intertriginous or flexural candidiasis behind the knee showing an extensive erythematous scaling lesion and several smaller satellite lesions caused by C. albicans. (Courtesy Dr G. Hunter, Adelaide, S.A.).
064

20. 065. Satellite lesions of cutaneous candidiasis showing typical collars of scale. C. albicans was isolated. Note the presence of satellite lesions usually differentiates candidiasis from dermatophytosis.
065

21. 068. Chronic candidiasis (onychomycosis) of thumb nails showing destruction of nail tissue. C. albicans was isolated. (Courtesy Dr G. Hunter, Adelaide, S.A.).
068

22. 069. Chronic candidiasis (onychomycosis) of thumb nails showing destruction of nail tissue. C. albicans was isolated. (Courtesy Dr G. Hunter, Adelaide, S.A.).
069

23. 071. Young infant with chronic superficial candidiasis showing spread to the mouth area and conjunctiva. Note erythematous scaling lesions with well marginated borders and small satellite lesions on the chin showing typical collar of scaling. C. albicans was isolated. (Courtesy Dr G. Hunter, Adelaide, S.A.).
071

24. 075. Chronic candidiasis of the scalp in a child with an underlying immune deficiency caused by C. albicans.
075

25. Candida - Laboratory Diagnosis 1
Specimens - Blood, tissue (biopsy or autopsy), sterile fluid, urine, CSF, skin, respiratory secretions
Microscopy (direct on specimen - except blood and urine)
Gram stain, Calcofluor
Histopathology (tissues)
H & E - stain poorly
GMS, PMS - stain well

26. Candida - Laboratory Diagnosis 2
Culture (all specimens)
Colony morphology
White, smooth, creamy, sometimes wrinkled
Laboratory identification
Unique color on chromagar
Chlamydospore production (terminal vesicle)
Germ tube production (in horse serum)
beginning of true hypha (no constriction)
C. albicans - Germ tube positive
Other Candida - Germ tube negative
Carbohydrate assimilation and fermentation (API 20C, Vitek2, RapID and reference)
Urea and nitrate
Microscopic morphology on Cornmeal Tween 80

27. Candida species Candida albicans Sabouraud Agar
Morphology: Creamy white yeast,
may be dull, dry irregular and
heaped up, glabrous and tough
Chromagar
producing green pigmented colonies
on specially designed medium to
speciate certain yeasts based on
color they produce

28. Candida species
Germ tube: inoculation of yeast in horse serum incubated at 370C for 2 to 3 hours
Germ Tube: Positive
Germ tube is a continuous filament
germinating from the yeast cell without constriction at the point of attachment.
e.g. C. albicans, C. dubliniensis
Germ Tube: Negative
Shows constriction at the attachment site
e.g. other Candida species, esp. C. tropicalis

29. Candida species Candida albicans Oxgall Agar large round and thick
walled chlamydospores
Cornmeal Agar
clusters of
blastospores along
pseudohyphae at regular
intervals
x400
x1000
x400
x1000

30. 076. Skin scraping mounted in 10%KOH from superficial candidiasis showing clusters of budding yeast cells and branching pseudohyphae.
076

31. 077. Direct smear of urine from a patient with candidiasis of the kidney showing C. albicans in mycelial or tissue phase with blastoconidia budding from the pseudohyphae.
077

32. 078. Periodic Acid-Schiff (PAS) stained section of post-mortem oesophagus showing invasion of blood vessel by C. albicans. Note blastoconidia and branched pseudohyphae.
078

33. 079. Candida albicans on Sabouraud's dextrose agar showing typical cream coloured, smooth surfaced, waxy colonies.
079

34. 080. Microscopic morphology of C
080. Microscopic morphology of C. albicans showing budding spherical to ovoid blastoconidia.
080

35. 081. Screening test for the identification of C. albicans
081. Screening test for the identification of C. albicans. Production of germ tubes by C. albicans in serum or plasma after 2-3 hours incubation at 37OC. Note characteristic germ tubes.
081

36. 082. Germ tube negative Candida species showing no production of germ tubes in plasma after 3 hours incubation at 37OC. Budding blastoconidia only are seen.
082

37. 083. Confirmatory test for C. albicans
083. Confirmatory test for C. albicans. Production of large round, thick-walled vesicles (often incorrectly referred to as chlamydoconidia) on Difco chlamydospore agar. Trypan blue in the medium is absorbed strongly by these terminal vesicles. Numerous small blastoconidia and pseudohyphae are also present.
083

38. 084. Uni-Yeast-Tek plate showing common assimilation tests and dalmau plate culture used for the identification of yeasts. Note morphological studies are essential for the satisfactory identification of yeasts. Also note the negative urease test indicating the ascomycetous nature of Candida albicans, the test organism.
084

39. 086. Auxacolor yeast identification strip showing the identification of Candida.

40. 087. CHROMagar Candida plate showing chromogenic colour change for C
087. CHROMagar Candida plate showing chromogenic colour change for C. albicans (green), C. tropicalis (blue), C. parapsilosis (white) and C. glabrata (pink).
087

41. 092. Candida dubleniensis and Candida albicans on CHROMagar.

42. 093. Candida dubleniensis and Candida albicans on Bird Seed Agar.

43. Candida - Treatment Remove infected intravenous lines
Antifungal therapy for systemic infection
Amphotericin B IV
Azoles (fluconazole, itraconazole, voriconazole, posaconazole) orally, intravenous
Flucytosine (only with Ampho B because of resistance)
Echinocandins (caspofungin, micafungin)

44. Candida antifungal resistance
Primary (inherent) resistance
C. lusitaniae (amphotericin B)
C. glabrata (fluconazole)
C. krusei (fluconazole)
Secondary (acquired) resistance
Fluconazole, other azoles
Amphotericin B
5-FC

45. Candida antifungal susceptibility testing
Testing methodology
Reference broth microdilution (CLSI)
Commercial broth microdilution with alamar blue (Sensititre, YeastOne)
E-test
Disk diffusion (CLSI
Vitek 2

46. Candida antifungal susceptibility testing

47. Candida antifungal susceptibility testing