Finchfetch Microorganisms -

Culture Medias

1 Nickerson’s Medium or Bismuth Sulfite Glucose Glycine Yeast (BSGG) This medium is used to stimulate the production of germ tubes, a characteristic of Candida albicans.

2 Cornmeal Agar with Tween 80 It is used for the identification of Candida species by promoting the formation of chlamydospores, which is a characteristic of Candida albicans.

3 CHROMagar Candida This differential medium allows for the isolation and identification of Candida species based on colony color. Candida albicans usually forms green colonies on this medium.

4 RPMI 1640 Medium It is a rich medium that contains inorganic salts, glucose, amino acids, vitamins, and other nutrients that promote the growth of yeast cells.

5 Potato Dextrose Agar (PDA) Potato Dextrose Agar (PDA) consists of a nutrient-rich substrate, made from dehydrated Potato Infusion and Dextrose, ideal for robust mycological propagation. Agar provides the solidifying medium. Acidification, typically using sterile tartaric acid, adjusts the pH to 3.5 +/- 0.1 to create a more selective environment by inhibiting bacterial proliferation. Additionally, Chloramphenicol is incorporated as an antimicrobial agent to further suppress bacterial contamination, thereby facilitating the selective isolation of fungi.

6 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.

About

Candida albicans is a fungus that lives on your body in small amounts, located in your mouth, skin and intestines. Candida is yeast that is responsible for infections like thrush and vaginal yeast infections if it is off-balance with healthy bacteria in your body. Infections are common and treated with antifungal medications. Though usually a harmless part of the human microbiota, C. albicans can become pathogenic under certain circumstances. Opportunistic infections are more common in hosts with compromised immunity, those experiencing neutropenia, or those receiving broad-spectrum antibiotic or steroid treatments. Invasive medical procedures can also heighten the risk of infection., C. albicans ability to cause disease is supported by various virulence factors. These include a fibronectin receptor and a hydrophobic molecule on the surface, which promote adherence to the epithelium of the host, aiding its survival within the host. Further, its ability to switch phenotypes and produce aspartyl protease and phospholipase increase its pathogenic potential. In summary, the pathogenesis of C. albicans is primarily attributed to its morphological versatility, opportunistic behavior, and an array of virulence factors that facilitate adherence, colonization, and tissue invasion in the host.

Characteristics

Candida albicans, a gram-positive, diploid yeast-like fungus, C.albicans can exhibit a range of morphological states depending on the environmental conditions. It is distinctive in its ability to form yeast, pseudohyphae, or true hyphae, and these adaptations are central to its ability to invade tissues. One unique characteristic of C. albicans is its ability to generate chlamydospores. These are large, thick-walled structures typically measuring 7-13 micrometers in diameter, predominantly found at the ends of hyphae or along pseudohyphae.

Manifestation

Candida albicans is implicated in a host of infections affecting both healthy individuals and those with compromised immunity. When C. albicans grows excessively, it can lead to an infection known as thrush, characterized by a white cottage cheese-like film. This acute infection is also known as pseudomembranous candidiasis. Among the various diseases caused by C. albicans, the following are key: - Oropharyngeal candidiasis or oral thrush, a common issue among individuals with HIV/AIDS. - Vulvovaginal candidiasis or vaginal thrush, prevalent in pregnant women and those with diabetes. This infection can arise due to the suppression of vaginal lactobacilli by antimicrobial treatments, leading to an overgrowth of C. albicans and resulting in Candida vaginitis. - Candidemia or disseminated infections, pneumonia, and meningitis, primarily seen in patients with compromised immunity or serious illness. Other conditions associated with Candida include paronychia, onychomycosis, endocarditis, eye infections, and intertriginous candidiasis.

Laboratory Diagnosis

Laboratory diagnosis of Candida albicans infection depends on the disease presentation and type of sample collected such as urine, vaginal discharge, CSF, sputum, blood or mucosal exudates. Microscopy can reveal Candida yeast cells in both unstained wet preparations and Gram-stained preparations. In the latter, C. albicans appears as gram-positive budding yeast cells (blastoconidia) or pseudohyphae with regular constriction points. Culture techniques are generally effective for detecting Candida species, and C. albicans grows well on Sabouraud dextrose agar and other common bacteriological media. After 24-48 hours of incubation at 25-37°C, colonies appear as cream-colored and pasty with a distinctive yeast smell. C. albicans can be recognized by hyphal elements radiating from colonies on blood-containing media within 48 hours, resembling feet or stars. These colonies may be mistaken for Staphylococcus spp, hence careful examination, possibly through wet mount or Gram staining, is necessary when analyzing high vaginal swab cultures. The carbohydrate fermentation test can differentiate C. albicans from other Candida species, such as C. tropicalis, C. parapsilosis, C. krusei, and C. glabrata. Moreover, a simple germ tube test can presumptively identify C. albicans. Molecular methods, including Fluorescence In Situ Hybridization (FISH) techniques like the Yeast Traffic Light PNA FISH assay, can identify and differentiate Candida species within an hour from positive blood cultures, providing quick and accurate identification for optimal treatment.