Candida glabrata is a yeast, a single-celled fungus, naturally present in the human body, often harmlessly as part of the normal microflora in the gastrointestinal and genitourinary tracts. However, it is an opportunistic pathogen that can cause infections, especially in individuals with compromised health, making its clinical understanding important in healthcare settings.
Characteristics and Clinical Significance
Candida glabrata commonly resides on human mucosal surfaces, such as the mouth, gastrointestinal tract, and genital area. Unlike some other Candida species, it does not typically form hyphae, which are filament-like structures often associated with increased invasiveness. Its ability to cause disease is linked to adherence to host tissues and medical devices, and its capacity to form biofilms, which are protective communities of cells.
A defining characteristic of Candida glabrata is its inherent reduced susceptibility to azole antifungal drugs like fluconazole. This intrinsic resistance means that even before exposure, many C. glabrata strains are less affected by these drugs compared to Candida albicans. This reduced susceptibility poses a challenge for treatment, as standard antifungal therapies may be less effective, often necessitating alternative drug choices.
Common Infections and Symptoms
Candida glabrata can cause a range of infections, varying in severity from superficial to life-threatening systemic conditions. One serious manifestation is candidemia, a bloodstream infection where the yeast enters the bloodstream. Symptoms can be vague, often presenting as fever and chills that do not respond to antibiotic treatment for bacterial infections.
It is also a common cause of urinary tract infections (UTIs), particularly in hospitalized patients. Symptoms of UTIs may include a frequent urge to urinate, painful or burning urination, and sometimes cloudy or blood-tinged urine, along with lower abdominal discomfort. Less commonly, it can cause oral candidiasis (thrush), characterized by painful white patches in the mouth. Vaginal yeast infections may present with itching, burning, irritation, and abnormal vaginal discharge.
Risk Factors for Infection
Several factors increase susceptibility to Candida glabrata infections. A weakened immune system is a primary risk factor, seen in conditions such as organ transplantation, cancer patients undergoing chemotherapy, and individuals with HIV/AIDS. When the immune system is compromised, the body’s natural defenses are less capable of controlling the yeast’s growth, allowing it to proliferate and cause disease.
Prolonged use of broad-spectrum antibiotics can disrupt the natural balance of microorganisms in the body by eliminating beneficial bacteria. This disruption creates an environment where Candida glabrata, which is not affected by antibacterial drugs, can overgrow. The presence of indwelling medical devices, such as urinary catheters or central venous catheters, also significantly increases risk. These devices provide surfaces for the yeast to adhere to and form biofilms, making them harder for the immune system and antifungal drugs to reach. Underlying medical conditions like diabetes, especially when blood sugar levels are not well-controlled, also predispose individuals to infections. High glucose levels create a more favorable environment for yeast growth and impair immune function.
Diagnosis and Treatment Approaches
Accurate diagnosis of Candida glabrata infection typically begins with laboratory testing. Culturing samples from the suspected site of infection, such as blood, urine, or tissue, is a common method to identify the presence of the yeast. Once Candida glabrata is isolated, antifungal susceptibility testing is performed. This testing is crucial due to the yeast’s known reduced susceptibility to many antifungal drugs, particularly azoles. Susceptibility testing determines which antifungal medications are most likely to be effective against the specific strain of C. glabrata causing the infection.
Treatment approaches for Candida glabrata infections emphasize the use of antifungal agents to which the specific strain is susceptible. Given its reduced susceptibility to azoles, other classes of antifungal drugs are often preferred as initial treatment. Echinocandins, such as caspofungin, micafungin, or anidulafungin, are frequently recommended as first-line therapy for invasive infections due to their potent activity.
Amphotericin B is another effective option for severe or resistant cases, though its use may be limited by side effects. Treatment plans are typically individualized based on the results of susceptibility testing, the severity and location of the infection, and the patient’s overall health. In some cases, a combination of antifungal drugs might be considered, especially for persistent or highly resistant infections.