Candida Species

Epidemiology Most common fungal pathogen 4th most common nosocomial infection 75% of women may become infected at least once in their lifetime Common infection in patients with AIDS , cancer ( ex:-leukemia) Most common fungus affecting immunecompromised

Mycology Yeast like fungus There are 6 species that infect man C. tropicalis, C. glabrata, C. parapsilosis, C.kusei, & C. lusitaniae The most common species is Candida albicans Found in mouth , vagina and intestinal tract in small colonies suppressed by immune system and other flora

Candida albicans

Morphology solitary, unicellular reproduction via budding rounded shape moist & mucous colonies

Pathogenesis Surface molecules that permit adherence of the organism to other structures (eg, human cells, extracellular matrix, prosthetic devices) Acid proteases and phospholipases that involve penetration and damage of cell envelopes Ability to convert to a hyphal form (phenotypic switching)

Virulence assay of different C. albicans strains using the skin equivalent

Figure 1. skin equivalent before infection

Figure 2. Infection with pathogenic clinical isolate of C. albicans. After 48 h the yeast penetrates the skin equivalent and destroys the tissue

Figure 3. Infection with non-pathogenic C. albicans Figure 3. Infection with non-pathogenic C. albicans. This strain is not able to penetrate into the tissue and thus behaves as a virulent as shown in the mouse model of systemic infection

How Does It Cause Disease ? Effects on immune system Disturb immune system Stimulate the body to form autoantibodies Induce endocrinopathies IgA protease Contain glycoproteins that stimulate mast cells to release histamine and prostaglandins

How Does It Cause Disease Effects of its growth It assimilates all sugars except lactose. It depresses the activity of lactase. Dietary carbohydrates are fungal growth promoters and associated with increased adherence of Candida species to mucosal epithelial cells. Release of toxic fungal metabolites.

Risk Factors of Infection Physiological:- Pregnancy, age (elderly & infants) ,Diet high in sweets, fruit juices, alcohol Trauma:- Infection, burn wounds. Haematological:- Neutropenia, cellular immunodeficiency (leukemia, lymphoma, AIDS, aplastic (anemia

Risk Factors of Infection Endocrinological:- Diabetes mellitus, Addison’s disease, hypoparathyroidism Iatrogenic:- Chemotherapeutics, corticosteroids, oral contraceptives, antibiotics catheters, surgery Others:-Intravenous drugs, malnutrition, malabsorption, Chronic Stress

Diseases by C. albicans Thrush Esophagitis Cutaneous candidiasis Genital candidiasis Deep candidiasis Note:- Esophagitis and Deep Candidiasis occur only in immuncompromised patients

Thrush Common in infants (Considered normal unless it lasts longer than a couple of weeks.) Diabetics are more likely to get oral thrush because the extra sugar in their saliva acts like food for Candida. High antibiotics doses or prolonged use increases the risk of oral thrush. Antibiotics kill some of the healthy bacteria that help keep Candida from growing too much. Poorly fitting dentures are increases the risk of thrush. Common in immunocompromised hosts,such as those with HIV infection.

multiple white plaques on lips, gingivae, tongue, and palate Thrush appears as whitish, velvety lesions in the mouth and on the tongue. Underneath the whitish material, there is red tissue that may bleed easily. The lesions can slowly increase in number and size. Oral thrush multiple white plaques on lips, gingivae, tongue, and palate

Oropharyngeal Thrush Features Pseudo membranous

Oropharyngeal Thrush Features Atrophy of tongue

Oropharyngeal Thrush Features Angular chelitis

Candida Esophagitis

Cutaneous Candidiasis This child has a large rash caused by Candidiasis, affecting the skin around the mouth. There are also other lesions that aren't connected to the large lesion, called "satellite lesions".

Vulvovaginal Candidiasis (VVC) Vulvar component often dominant Women are often misdiagnosed as having VVC when they really have - Genital herpes - Contact dermatitis - Lichen planus - Atrophic vaginitis - Recurrent BV (Bacterial Vaginosis)

Vulvovaginal Candidiasis

Deep Candidiasis Four forms of invasive candidiasis Catheter related candidemia Acute disseminated candidiasis Chronic disseminated candidiasis Deep organ candidiasis

Candidemia Onchomycosis Nail infections are much more difficult to cure and can last a lifetime without proper treatment

Candidemia Hematogenous seeding Spread to the eye Can cause blindness

Laboratory diagnosis Specimen Scrapings of surfaces

Visualization of pseudohyphae (mycelia) and/or budding yeast (conidia) Laboratory diagnosis Slide preparations Visualization of pseudohyphae (mycelia) and/or budding yeast (conidia) KOH or saline

Staining Laboratory diagnosis Lacto phenol blue Gomoris methylamine sliver stains (GMS)

Laboratory diagnosis Culture Sabourauds glucose agar medium Brain heart infusion.

Serology CFT Latex agglutination ELISA Fluorescent Abs Laboratory diagnosis Serology CFT Latex agglutination ELISA Fluorescent Abs

Laboratory diagnosis Other Diagnostic Methods Skin test PCR

Candida culture

Immunofluorescence

Treatment of Candida albicans Dietary :- Eliminate all sugar: –fruit juice –white flour –refined grains Eat a higher protein, lower carbohydrate and high fiber diet. Avoid fermented foods including alcohol.

Treatment of Candida albicans Antifungal drugs:- Amphotericin B (Fungizone) Clotrimazole (Mycelex) Fluconazole (Diflucan) Itraconazole (Sporanox) Ketoconazole (Nizoral) Nystatin (Mycostatin)