MIDTERM: AGENTS OF YEAST Flashcards
YEAST fungi can be classified into one of two groups:
yeasts and yeastlike fungi
Isolates that reproduce sexually, either by forming ascospores or basidiospores
Yeast
not capable of sexual
reproduction or whose sexual state has not yet been discovered
Yeastlike fungi
Most common recognized yeast pathogens
Candida spp.
species most commonly isolated from clinical material
Candida albicans
Since Candida spp. are a part of the normal flora in the _______, infections generally occur as the result of an opportunity
GI tract, mucous membranes and skin
Invasive disease by Candida spp. Develops when the host defenses are _____
compromised
_________ as a result of disease (e.g. AIDS) or treatment with high dose chemotherapy are common risk factors
Diabetes, immunosuppressive disease or therapy and neutropenia
Bloodstream infections including _______, are fostered by the use of indwelling vascular lines
fungal endocarditis
All candida spp. exist as _______
oval yeastlike forms that produce buds or blastoconidia
Candida spp. produce hyphae and pseudohyphae except for _____
Candida glabrata
notable consume of sugar
TREHALOSE (second most common species of Candida)
C. glabrata
Usually from the people who drools while asleep (e.g. infants)
ANGULAR CHEILITIS (PERLECHE)
With the presence of the saliva in that area, that tissue would
become soft allowing the candida to infect the area
Lateral fissure
occurs as fungal infectiion on esophagus
Esophagitis
may have dysphagia as a result for painful lesions
Esophagitis
Occurs more frequently as esophagitis and less commonly as gastritis
Gastrointestinal Candidiasis
Erosive lesions of the distal esophagus and stomach resulting in substernal pain which is aggravated by swallowing
Gastrointestinal Candidiasis
Fungal Infection in the vagina
Vulvovaginitis
The vagina naturally contains a balanced mix of yeast (Candida) and bacteria.
Vulvovaginitis
____ act to prevent an overgrowth of yeast
Lactobacillus
But when the balance is disrupted hence the overgrowth of Candida or the fungus causes the signs and symptoms of yeast infection
Vulvovaginitis
Vulvovaginitis Factors:
- Antibiotic
- Pregnancy ( HIGH ESTROGEN = GLYCOGEN )
- Uncontrolled diabetes ( INC GLUCOSE)
- Impaired immune system
Vulvovaginitis discharge:
cottage cheese- vaginal discharge
Difficult to diagnose because this yeast are frequently recovered from the urine as a result of vaginal contamination or colonization of the bladder in patients with indwelling catheters
Urinary Tract Infection
Severe infection of the upper urinary tract, including ______, a serious complication that occurs particularly in patients who have obstructive uropathy
necrosis of the renal papillae
Involves sources other than the skin or mucous membranes
INVASIVE CANDIDIASIS
Most invasive infections caused by Candida albicans result in bloodstream invasion with hematogenous spread of the organism
INVASIVE CANDIDIASIS
isolation of Candida spp. from at
least one blood culture specimen with hematogenous spread of the yeast to one or more organs
Candidemia
Fungal infection of the nails
OONCHONYCHOMYCOSIS
Infection is frequently due to dermatophyte while non dermatophyte (NDM’s) such as Candida spp.
OONCHONYCHOMYCOSIS
Attributed especially in immunocompromised patients
OONCHONYCHOMYCOSIS
OONCHONYCHOMYCOSIS
If dermatophyte is the cause- ____
Tinea unguium
OONCHONYCHOMYCOSIS
Non-dermatophyte- _____
Candidal onychomycosis
Infection of the skin around the fingernail or toenail
PARONYCHOMYCOSIS
The infection area can become swollen, red and painful, and a pus-filled blister (abscess) may form
PARONYCHOMYCOSIS
Common infection among immunocompetent individual
INTERTRIGINOUS CANDIDIASIS
Commonly seen in the axillae, groin, inter and submammary
folds, intergluteal folds, interdigital spaces and umbilicus
INTERTRIGINOUS CANDIDIASIS
INTERTRIGINOUS CANDIDIASIS
Factors:
- Moisture
- Heat
- Friction
- Maceration of the skin
CANDIDAL DIAPER DERMATITIS
Usually from the people who drools while asleep (e.g. infants)
ANGULAR CHEILITIS (PERLECHE)
With the presence of the saliva in that area, that tissue would become soft allowing the candida to infect the area.
Lateral fissure
occurs as fungal infectiion on esophagus
Esophagitis
may have dysphagia as a result for painful lesions
Esophagitis
Occurs more frequently as esophagitis and less commonly as gastritis
Gastrointestinal Candidiasis
Erosive lesions of the distal esophagus and stomach resulting in substernal pain which is aggravated by swallowing
Gastrointestinal Candidiasis
Fungal Infection in the vagina
Vulvovaginitis
The vagina naturally contains a balanced mix of yeast (Candida) and bacteria.
Vulvovaginitis
______ act to prevent an overgrowth of yeast
Lactobacillus
But when the balance is disrupted hence the overgrowth of Candida or the fungus causes the signs and symptoms of yeast infection
Vulvovaginitis
Vulvovaginitis
Factors:
- Antibiotic
- Pregnancy ( HIGH ESTROGEN = GLYCOGEN )
- Uncontrolled diabetes ( INC GLUCOSE)
- Impaired immune system
Vulvovaginitis discharge
Cottage cheese- vaginal discharge
Difficult to diagnose because this yeast are frequently recovered from the urine as a result of vaginal contamination or colonization of the bladder in patients with indwelling catheters
Urinary Tract Infection
Severe infection of the upper urinary tract, including _________, a serious complication that occurs particularly in patients who have obstructive uropathy
necrosis of the renal papillae
Involves sources other than the skin or mucous membranes
INVASIVE CANDIDIASIS
Most invasive infections caused by Candida albicans result in bloodstream invasion with hematogenous spread of the organism
INVASIVE CANDIDIASIS
isolation of Candida spp. from at
least one blood culture specimen with hematogenous spread of the yeast to one or more organs
Candidemia
Fungal infection of the nails
OONCHONYCHOMYCOSIS
Infection is frequently due to dermatophyte while non dermatophyte (NDM’s) such as Candida spp.
OONCHONYCHOMYCOSIS
Attributed especially in immunocompromised patients
OONCHONYCHOMYCOSIS
OONCHONYCHOMYCOSIS
If dermatophyte is the cause- ___
Tinea unguium
OONCHONYCHOMYCOSIS
Non-dermatophyte-
Candidal onychomycosis
Infection of the skin around the fingernail or toenail
PARONYCHOMYCOSIS
The infection area can become swollen, red and painful, and a
pus-filled blister (abscess) may form
PARONYCHOMYCOSIS
Common infection among immunocompetent individual
INTERTRIGINOUS CANDIDIASIS
Commonly seen in the axillae, groin, inter and submammary
folds, intergluteal folds, interdigital spaces and umbilicus
INTERTRIGINOUS CANDIDIASIS
INTERTRIGINOUS CANDIDIASIS
Factors:
- Moisture
- Heat
- Friction
- Maceration of the skin
Also known as DIAPER RASH
CANDIDAL DIAPER DERMATITIS
Candida grows best in warm, moist such as diaper
CANDIDAL DIAPER DERMATITIS
More likely to occur in babies who are not kept clean and dry
CANDIDAL DIAPER DERMATITIS
Common in CHILDREN
CANDIDAL DIAPER DERMATITIS
VIRULENCE FACTORS of C. albicans:
Adhesins
Invasins
Biofilm formation
C. albicans invasuon process:
Adhesion
Uptake
Penetration
Yeast cells stick to host cells using adhesins, triggering a switch to hyphal form and growth towards the host.
Adhesion
Invasins facilitate host cell engulfment of the fungus through stimulated endocytosis.
Uptake
The combination of adhesion, physical force, and fungal enzymes may enable active penetration through host cell
barriers.
Penetration
Yeast cells can form biofilms on both living and non-living surfaces, consisting of yeast cells below and hyphae above
Biofilm formation
Additional factors:
phenotypic switching
Candida albicans can change its
surface features and biofilm formation abilities
phenotypic switching
Procurement of appropriate clinical material followed by direct microscopic examination and culture
MICROCOSCOPIC TEST
Scrapings of mucosal or cutaneous lesions may be examined directly after treatment with _______
10% - 20% potassium hydroxide (KOH) containing calcofluor white
Tissue specimens, scrapings and swabs from the mouth or vagina should be inoculated unto primary fungal isolation media
______ (the presence of filamentous extension from the edges of the colony is a macroscopic indication that pseudohyphae are being produced)
with or without cycloheximide
In Histologic sections, all Candida spp. Stain poorly with H&E but stains well with _____
PAS, Gomori Methenamine Silver and Gridley fungus dtains
Used to detect the characteristic chlamydoconidia produced by C. albicans; method is satisfactory for definitive identification of C. albicans when the germ test tube appears negative
CORNMEAL TWEEN 80 AGAR
Morphologic features of the common Candida spp. are distinct enough to provide a presumptive identification
CORNMEAL TWEEN 80 AGAR
Most generally accepted and economical method used in the clinical laboratory to identify yeasts; 80% of the yeasts recovered from clinical specimens are Candida albicans.
GERM TUBE TEST
Provides sufficient identification of the organism within 3 hours
GERM TUBE TEST
hyphae-like extensions of young yeast cells showing parallel sides, aseptate and will not constrict at their point of origin
germ tube
Candida spp positive in germ tube test:
C. albicans
C. dubliniensis
germ tube test (+) C. dubliniensis @ _____
35⁰ C
germ tube test (+) C. Albicans @ _____
35 ⁰ C & 42 ⁰ C
look like germ tubes but are septate pconstricted at the point of their origin
pseudohyphae
produce “pseudo-germ tubes” which are constricted at the base or point of germ tube origin
Candida tropicalis
c. tropicalis in pseudohyphae = _____
blastoconidial germination w/ constriction
Most commonly used conventional definitive identification of yeasts recovered in clinical laboratory
CARBOHYDRATE ASSIMILATION TEST
All candida spp. use glucose in CAT
CARBOHYDRATE ASSIMILATION TEST
Colony of C. Albicans:
smooth, white, creamy, domed
colonies
C. albicans and other spp. may also undergo ______, in which a single strain may change reversibly among several different morphotypes
phenotypic switching
Most frequent infection caused by Candida albicans; presents topically as an _______, sometimes
accompanied by a creamy, white exudate or scaling
erythematous lesion of the skin
Moist conditions such as ______ in adults, are precursors to infectio
diaper rash in infants and infection of skin folds (intertrigo)
Common sites are those in groin, between fingers and toes, under the female breast and in the axilla
intertriginous candidiasis
Workers who immerse their hands in the water for long periods of time are also at risk for
infection of the skin of the hands, the nails _____ or the nail bed ____
onychomycosis; paronychium
Manifest as the appearance of creamy white patches overlying erythematous buccal mucosa
(thrush/white stuff on the mouth/white cottage-cheese like patches on the mouth);
Oral Candidiasis/Moniliasis
is recognised as an indicator of
immunosuppression ( HALLMARK OF FAILED IMMUNE SYSTEM )
thrush
Symptoms usually minimal, _____ may occur in heavy infection
dysphagia
______ is a common initial infection in patients with HIV and frequently is a marker of immune failure in these patients
Oral candidiasis
Characterized as an inflammatory condition that affects the commissures of the mouth, causing break in the tissue with redness, crusting, and scaling.
ANGULAR CHEILITIS (PERLECHE)
This is often caused by the accumulation of saliva in the
fissures
ANGULAR CHEILITIS (PERLECHE)
