Candida species

Candida species are a group of yeasts (a type of fungus) that are commonly found in the environment and on or inside the human body. These organisms are part of the normal microbiota, meaning they live harmlessly on the skin, in the mouth, digestive tract, and genital area of many healthy people.

Under certain conditions, Candida can overgrow and cause an infection. These infections, known as candidiasis, are more likely to occur when a person’s immune system is weakened or after antibiotics disrupt the normal balance of bacteria.

What are the most common Candida species?

The most common species is Candida albicans, but other species, such as Candida glabrata, Candida tropicalis, and Candida krusei, are becoming increasingly common.

What types of infections can Candida cause?

Candida can cause both mild and severe infections, depending on the individual’s overall health and the location of the infection.

Common superficial infections:

• Oral thrush – white patches in the mouth or throat, often with pain or trouble swallowing.

• Vaginal yeast infections – itching, thick white discharge, discomfort during urination or sex.

• Skin infections – red, itchy rashes in moist areas such as the groin, underarms, or under the breasts.

• Urinary tract infections (UTIs) – may cause burning, urgency, or cloudy urine.

Invasive and severe infections:

• Candidemia – infection in the bloodstream, often seen in people who are hospitalized or have weak immune systems.

• Infections in organs – such as the liver, kidneys, eyes (endophthalmitis), or bones (osteomyelitis).

• Esophageal candidiasis – often seen in people with HIV or weakened immune systems, causing pain when swallowing and chest discomfort.

Who is at risk for Candida infections?

Anyone can get a Candida infection, but the risk is higher in people with:

• Weakened immune systems (due to cancer, HIV, or chemotherapy).

• Diabetes.

• Recent antibiotic use.

• Long hospital stays, especially in the ICU.

• Medical devices like catheters, feeding tubes, or central lines.

• Recent surgery, especially involving the gastrointestinal tract.

• Preterm infants with low birth weight.

• Poorly controlled blood sugar or recent use of steroids.

What is Candida auris?

Candida auris is a newer and more serious species of Candida that is resistant to many medications. It can cause life-threatening infections, especially in people in long-term care facilities or hospitals. It spreads easily from person to person and is difficult to eliminate from healthcare settings.

Since its first case in the U.S. in 2016, the number of infections has been increasing. The U.S. Centers for Disease Control and Prevention (CDC) is closely tracking C. auris.

How is Candida diagnosed?

Diagnosis depends on where the infection is:

• Swabs or scrapings from the mouth, vagina, or skin can be examined under a microscope.

• Urine or blood cultures may be done to detect Candida in the urinary tract or bloodstream.

• Tissue samples may be tested in more serious cases.

Candida usually appears under the microscope as oval, budding yeast cells, sometimes with pseudohyphae (chains of elongated cells). Special stains such as PAS or silver stains may be used to help detect Candida in tissue samples.

Laboratories can also use:

• Culture tests on special media (e.g., CHROMagar).

• PCR testing for rapid identification.

• Germ tube testing to distinguish C. albicans from other species.

• MALDI-TOF mass spectrometry for precise species identification.

Candida species in your pathology report

If Candida species are mentioned in your pathology report, it means that yeast organisms consistent with Candida were seen in the tissue or fluid sample that was examined. This may be based on what the cells look like under the microscope, the results of special stains, or a culture.

Candida may be described in several ways, such as:

• Budding yeast with pseudohyphae – common in Candida albicans infections.

• Fungal organisms consistent with Candida – seen with routine or special stains like PAS or GMS.

• Positive culture for Candida species – from urine, sputum, blood, or tissue samples.

In some cases, Candida may be present as part of the normal microbiota and not cause disease. In other cases, especially when Candida is found in tissue or a normally sterile site (like blood or an organ), it suggests a true infection.

Your doctor will interpret this finding in the context of your symptoms, immune status, and other test results to decide whether treatment is needed.

How are Candida infections treated?

Treatment for Candida depends on the type and location of the infection:

Mild or superficial infections:

• Topical treatments like clotrimazole, miconazole, or nystatin.

• Oral fluconazole may be used if symptoms are more severe or widespread.

Invasive infections:

• Fluconazole is often the first choice.

• Echinocandins or amphotericin B may be used for resistant strains or severe infections.

• Some Candida species are harder to treat:

  • C. krusei is naturally resistant to fluconazole.

  • C. glabrata often shows reduced response to common antifungals.

Your doctor will choose the most effective treatment based on the type of Candida, the location of infection, and your overall health.

Questions to ask your doctor

• What type of Candida infection do I have?

• How serious is the infection?

• What treatment is recommended, and how long will it last?

• Are any further tests or follow-up appointments needed?

• How can I prevent future Candida infections?