Candida glabrata Overview

Table of Contents

• What is Candida glabrata?
• Habitat of Candida glabrata
• Morphology of Candida glabrata
• Pathogenesis of Candida glabrata
• Virulence Factors
• Clinical Manifestations of Candida glabrata
• Superficial infection
• Systemic Candidiasis
• Laboratory Diagnosis of Candida glabrata
• Specimens
• Staining and Microscopic Examination
• Cultural Examination
• Biochemical Tests
• Molecular Based Tests
• Treatment of Candida glabrata infections
• Prevention and Control of Candida glabrata infections

What is Candida glabrata?

Previously known as Torulopsis glabrata, Candida glabrata is a member of the order Moniliaes, family Cryptococcaceae, and class Fungi Imperfecti.

• One of the most prevalent species of candida, C. glabrata, coexists commensally with its human host.
• In healthy people, it does not result in illness.
• However, it has been shown that it can also lead to candidiasis in those with underlying illnesses that have immune system suppression, including as HIV/AIDS patients, diabetics, chemotherapy patients, organ transplant recipients, and patients undergoing inpatient surgery.
• As a result, it is a recognised pathogenic candidal species that causes candidiasis infections in hosts with compromised immune systems.
• It frequently results in urogenital tract infections and systemic infections when they enter the circulation, particularly in people with impaired immune systems.
•  Currently, C. glabrata is the second or third most common nosocomial cause of systemic or superficial (oral, esophageal, vaginal, or urinary) candidal infections.
• Azole, amphotericin B, or flucytosine are all effective treatments for C. glabrata infections.

Habitat of Candida glabrata

• C. glabrata is mostly found in human hosts but may also be found in a variety of situations.
• They frequently exist as typical microflora in the gastrointestinal tracts of animals.
• Additionally, it has been isolated from the oral cavity, genitourinary tract, alimentary tract, and respiratory tract of the human host.

Morphology of Candida glabrata

• Candida glabrata is a nondimorphic species that only has little blastoconidia, in contrast to other candidal species that are dimorphic in nature.
• It is the only species of Candida that does not produce pseudohyphae at temperatures over 37 °C.
• The blastoconidia of Candida glabrata are relatively tiny, measuring just 1 to 4 μm as opposed to the 4 to 6 μm of the blastoconidia of Candida albicans.
• When C. glabrata colonies are isolated on Sabouraud dextrose agar, they produce glistening, smooth, cream-colored colonies that are very tiny in size but yet resemble those of other Candidal species.
• In contrast to C. albicans colonies, which are green to blue-green, C. glabrata colonies on Chromagar, a distinct medium for Candidal species, create colonies that are pink to purple.
• In contrast to other Candidal species, which have a diploid genome, they contain a haploid genome with tiny RNA components.

Pathogenesis of Candida glabrata

• Despite their relatively low pathogenicity, their isolation from different patient samples suggests that they play a role in the adhesion, colonisation, and development of candida-related illnesses.
• Its poor virulence and pathogenicity have been linked to the absence of laminin, fibronectin, and pseudohyphae production, as well as adhesin receptor proteins.
• Although the immune system's defences against Candida glabrata are poorly understood, it has been established that this species causes systemic candidiasis and candidemia in humans.

Virulence Factors

• In order to bind with the adhesin receptors on the host cells, adhesion factors to epithelial and endothelial cells have been linked to the fungus' hydrophobic cell surface. However, compared to other Candida species, its adherence parameters are also modest.
• Candida glabrata generates far less protease than Candida albicans, according to data on protease synthesis.
• Phenotypic switching has been detected on Candida glabrata which allows it to switch colony phenotypes without affecting the genotype of the species, which has been associated with the virulence of its virulence among other Candidal species.

Clinical Manifestations of Candida glabrata

Superficial infection

• Oropharyngeal, esophageal, and vaginal candidiasis have all been linked to symptomatic mucosal infection by Candida glabrata in HIV/AIDS patients and other immunocompromised individuals.
• Acute pseudomembranous candidiasis, sometimes called oral thrush, is linked to oropharyngeal candidiasis.
• It manifests as asymptomatic erythematous forms and is the earliest indicator of HIV infection and AIDS progression.
• The spread of the illness from the oropharyngeal lining is linked to esophageal candidiasis.
• Common in females, pregnant people, and diabetics, vulvovaginal candidiasis is linked to mild to moderately severe candidiasis.
• Candida infection in the urinary tract, commonly known as candiduria, affects hospitalised patients with invasive catheters, those with diabetes mellitus, the elderly, and people who are weak and taking antibacterial treatments. However, Candida glabrata is not associated with complex hematogenous infections of the urinary tract.

Systemic Candidiasis

• Candida glabrata seldom causes systemic candidiasis, however in people with weaker immune systems, dissemination has been discovered in the circulation, particularly in patients who have undergone bone marrow transplants and long-term hospitalisations. It has been connected to the long-term use of fluconazole antifungals and antibacterials.
• It spreads to other organ systems and results in the blood infection known as candidemia, which is accompanied by a lingering fever, declining health, and resistance to antifungal medications.
• C. glabrata often causes fungemia.

Laboratory Diagnosis of Candida glabrata

Specimens

Swabs, respiratory wash, vaginal swabs, blood

Staining and Microscopic Examination

KOH wet mount is used to distinguish one Candida species from other Candida species.

Cultural Examination

• On Sabouraud dextrose agar, C. glabrata grows in colonies that are smooth, glossy, and cream in color—similar to other Candidal species, but smaller.
• Candida glabrata develops colonies on Chromagar, a distinct medium for Candidal species, that are pink to purple in contrast to C. albicans colonies, which are green to blue-green.
• They can also be cultivated on bacterial blood cultures to test for the fungi's hemolytic properties.

Biochemical Tests

Contrary to other Candida species, which may assimilate a variety of carbohydrates, Candida glabrata can only ferment and absorb glucose and trehalose.

Molecular Based Tests

Comparative chromosomal DNA study to recognise and distinguish between various Candida species and strains

• Polymorphism in Restriction Fragment Length
• chromosomal molecular weight by dividing the chromosomal strands into distinct bands for strain identification using pulse-field gel electrophoresis.
• Candida glabrata strains show electrophoretic karyotypying (EK) patterns with 10–13 bands.
• DNA probing and random amplified polymorphism.

Treatment of Candida glabrata infections

• Topical polyene medications such nystatin, amphotericin B, Clotrimazole, triazoles, itraconazole, and fluconazole are used to treat oropharyngeal candidiasis in HIV/AIDS patients.
• Fluconazole, itraconazole, and intravenous amphotericin B are treatments for esophageal candidiasis.
• Butoconazole, miconazole, and clotrimazole have high antifungal action for vulvovaginitis, whereas terconazole, itraconazole, and ketoconazole have moderate activity. Fluconazole is ineffective in treating vulvovaginitis.
• Amphotericin B or fluconazole are used to treat the symptoms of candidiasis.
• Amphotericin B, including candidemia, is the gold standard therapy for systemic candidiasis. Low dosages of fluconazole are also beneficial.

Prevention and Control of Candida glabrata infections

• For patients with candiduria infection, stop catheterization
• hospitalised patients receiving preventative antifungal therapy