The human body naturally hosts various microorganisms, including different species of the yeast Candida. These yeasts commonly cause fungal infections, often called yeast infections. While most infections are caused by Candida albicans, Candida glabrata is becoming increasingly common and presents unique challenges. This organism raises questions about its transmission, particularly whether it can be passed through sexual contact. This article clarifies the nature of C. glabrata, its primary transmission pathways, and the clinical issues associated with its management.
Defining Candida Glabrata
Candida glabrata is a yeast species that is part of the normal microflora, naturally residing on and within the human body, particularly in the gastrointestinal tract, mouth, and genital area. For most healthy individuals, this yeast is a harmless commensal organism, held in check by the immune system. However, C. glabrata is an opportunistic pathogen, causing infection only when conditions allow it to overgrow or when a person’s defenses are weakened.
C. glabrata is the second or third most frequently isolated cause of candidiasis after C. albicans, and its prevalence is rising significantly in clinical settings. Unlike C. albicans, which can switch between a yeast form and thread-like hyphae, C. glabrata grows only as a yeast. This difference in morphology contributes to its unique behavior and ability to evade parts of the immune response.
Infections caused by C. glabrata are often more problematic than those from C. albicans, especially in hospital environments. It is frequently associated with severe, systemic infections, such as those in the bloodstream, and is a significant concern for individuals with compromised immune systems.
Transmission Pathways and Sexual Contact
The short answer is that C. glabrata is generally not classified as a sexually transmitted infection (STI), unlike diseases such as chlamydia or gonorrhea. C. glabrata infection, like other forms of candidiasis, is primarily an endogenous infection, arising from an overgrowth of the yeast already residing in the person’s body. This overgrowth often occurs when the balance of the local microbial environment is disturbed.
Factors that predispose an individual to an overgrowth of C. glabrata include the use of broad-spectrum antibiotics, which eliminate competing bacteria, and conditions that weaken the immune system, such as diabetes, HIV, or cancer treatment. Prolonged hospitalization, the presence of indwelling medical devices like central venous catheters, and recent surgical procedures are also significant risk factors. The infection is often a consequence of internal factors rather than external transmission.
While not an STI, sexual activity can still play a role in the transfer of the organism. Any type of sexual contact can facilitate the physical transfer of the organism from one mucosal surface to another, such as from the gastrointestinal tract to the genital area, or between partners. However, this transfer does not automatically result in an infection, as symptom development requires a favorable environment for the yeast to multiply. For the vast majority of cases, the infection originates from the host’s own existing yeast population, not from a partner.
Clinical Management and Antifungal Resistance
Infections caused by C. glabrata are clinically challenging due to the organism’s intrinsic and acquired resistance to common antifungal medications. A significant issue is its reduced susceptibility to azole drugs, particularly fluconazole, which is often the first-line treatment for yeast infections caused by C. albicans. This intrinsic low susceptibility means C. glabrata can often survive treatment with standard doses of fluconazole, leading to treatment failure.
The mechanism of resistance involves the organism’s ability to pump the drug out of its cells before it can be effective, a process mediated by the overexpression of specific drug transporter genes. Because of this resistance profile, clinicians must often rely on alternative antifungal drug classes, primarily echinocandins, such as caspofungin or micafungin, for initial treatment of serious infections. These drugs target the fungal cell wall, interfering with its structural integrity.
Managing C. glabrata infections requires antifungal susceptibility testing. This laboratory test determines which antifungal drugs are effective against the specific strain isolated from the patient. Identifying the susceptibility pattern is a critical step because resistance to both azoles and echinocandins is increasingly reported, posing a substantial threat to successful treatment.