Invasive Candidiasis

What invasive candidiasis is

Candida yeasts live harmlessly on skin and in the mouth, gut and vagina. They cause common surface infections, covered on our candidiasis page. Invasive candidiasis happens when Candida gets past the body's barriers into sterile sites.

The most common form is candidemia, Candida in the bloodstream. From the blood, yeast can seed almost any organ. Invasive candidiasis can also start directly in the abdomen after bowel surgery or a gut perforation, without first appearing in the blood.

Candida species are among the most common causes of bloodstream infections in US hospitals. Candida albicans was historically the main species, but others such as C. glabrata (now Nakaseomyces glabratus), C. parapsilosis and C. tropicalis are increasing. Candida auris is an emerging, often drug-resistant species that spreads between patients in healthcare facilities and is a CDC urgent threat.

Forms of invasive candidiasis

Risk factors

• Stay in an intensive care unit, especially for more than a few days.
• Central venous catheters (central lines) and IV nutrition (total parenteral nutrition).
• Broad-spectrum antibiotics, which kill bacteria that normally keep Candida in check.
• Abdominal surgery, especially with leaks from the bowel, and acute pancreatitis.
• Low white blood cell counts (neutropenia) from chemotherapy or blood cancers.
• Organ or stem cell transplant.
• Kidney failure and dialysis.
• Diabetes.
• Very low birth weight premature babies.
• Injection drug use.

Symptoms

Symptoms are often nonspecific, because most patients are already unwell:

• Fever and chills that do not improve with antibiotics. This is the classic clue.
• Signs of sepsis: fast heart rate, low blood pressure, confusion.
• Organ-specific symptoms listed above.
• Occasionally, small painless red skin nodules.

Diagnosis

• Blood cultures: the main test, but they miss up to half of deep-seated infections and take days to grow.
• Cultures and tissue from infected sites: fluid from the abdomen, abscesses, urine or bone.
• Beta-D-glucan blood test: a marker of fungal cell walls that can support the diagnosis. False positives occur.
• PCR and newer rapid tests where available.
• Species identification and susceptibility testing to choose the right drug.
• Dilated eye exam by an ophthalmologist for anyone with candidemia, ideally within the first week.
• Echocardiogram (heart ultrasound) when cultures stay positive or there is a valve risk.
• Imaging (CT, MRI, ultrasound) to find abscesses or organ involvement.

Treatment for invasive candidiasis

Treatment starts promptly, often before cultures confirm the diagnosis in high-risk patients.

Antifungal medicines

• Echinocandins (caspofungin, micafungin, anidulafungin, and the once-weekly rezafungin) given by IV are the usual first choice.
• Fluconazole may be used if the yeast is susceptible and the patient is stable, often as a step-down to tablets after 5 to 7 days.
• Amphotericin B for resistant species or certain sites such as the brain.
• Voriconazole or other azoles in specific situations, including eye infections.

For candidemia without spread, treatment continues for at least 2 weeks after the first negative blood culture and symptoms resolve. Eye, heart, bone and abscess infections need weeks to months.

Source control

• Removing central lines whenever possible.
• Draining abscesses and repairing bowel leaks.
• Valve surgery for many cases of Candida endocarditis.

Candida auris

C. auris is often resistant to fluconazole and sometimes to other classes. Hospitals use strict isolation and cleaning to prevent spread. Echinocandins are the usual first treatment.

Outlook

Invasive candidiasis is serious. Death rates in hospital patients with candidemia are around 25 to 40 percent, partly because people who develop it are already very ill. Starting antifungals and removing infected lines early improves survival. Survivors may have lasting effects if the eyes, heart or bones were involved.

Prevention

• Careful hand hygiene and central line care in hospitals.
• Removing central lines as soon as they are no longer needed.
• Using antibiotics only when needed.
• Preventive antifungal medicine for selected high-risk patients, such as some transplant recipients and patients with blood cancers.

Frequently asked questions

What is the difference between candidemia and invasive candidiasis?

Candidemia means Candida yeast in the bloodstream. Invasive candidiasis is the broader term, covering candidemia plus infection of deep organs such as the heart, eyes, kidneys, bones and abdomen. Deep infection can occur with or without yeast being found in the blood.

What are the symptoms of invasive candidiasis?

The most common symptoms are fever and chills that do not improve after antibiotics, usually in someone who is already in hospital. Other symptoms depend on the organ involved, such as blurred vision with eye infection, belly pain with abdominal infection, or bone pain with spinal infection.

Who is at risk of invasive candidiasis?

People in intensive care, those with central lines or IV nutrition, after abdominal surgery, on broad-spectrum antibiotics, with low white blood cell counts, transplant recipients, people on dialysis and premature babies are at highest risk. Healthy people in the community rarely get it.

How is invasive candidiasis treated?

It is treated with IV antifungal medicine, usually an echinocandin, sometimes followed by fluconazole tablets. Infected central lines are removed and abscesses drained. Treatment lasts at least 2 weeks after blood cultures clear, and longer if organs such as the eye or heart are involved.

Is Candida auris the same as invasive candidiasis?

No. Candida auris is one species of Candida that can cause invasive candidiasis. It is concerning because it is often resistant to antifungal drugs, can colonize skin for long periods and spreads in healthcare facilities. Most invasive candidiasis is still caused by other Candida species.