Candida auris

What is Candida auris?

Candida auris is a newly discovered harmful germ that can cause infections in hospitals and is seen as a serious worldwide health concern. It was first noticed as a new species of Candida, a type of fungus, in 2009 and has since been found in 35 countries (the only exception being Antarctica).

Candida auris can lead to severe infections with a high risk of death. It’s known to resist multiple drugs, showing varying levels of resistance to many standard antifungal drugs that are usually effective against other Candida infections. The growing number of infections and people getting Candida species that aren’t Candida albicans (another type of fungus) may be linked to the overuse of preventive antifungal medicines like fluconazole.

The labs that use yeast identification methods usually mistake Candida auris for other types of yeast, which makes it hard to detect and control this harmful germ. It can spread in hospitals, even those that follow infection prevention and control practices. In the United States, it’s compulsory to report cases of Candida auris to allow public health officials to keep track of and limit its spread.

What Causes Candida auris?

Candida auris is a type of yeast from the Candida genus. It got its name when it was first found in a patient’s external ear canal in a Japanese hospital. Studies on the yeast’s genetic material reveal it to be a unique species, with characteristics similar to other types of Candida such as Candida ruelliae, Candida haemulonii, C. duobushaemulonii, and C. pseudohaemulonii.

C. auris is a budding yeast, meaning it grows by producing new cells or buds. These cells may exist alone, in pairs, or in groups. The cells are oval or elongated in shape and measure between 2.5-5.0 micrometers. C. auris doesn’t usually create structures called hyphae or pseudohyphae, which are like branches in other fungi. Also, it doesn’t form germ tubes, which are extensions that help other types of fungi to grow. However, under certain conditions, like high-salt environments or when heat-shock proteins (proteins which help the cell to respond to stressful conditions) are depleted, it can grow pseudohyphae, structures somewhat like regular hyphae.

C. auris can grow well at 40 degrees Celsius, but it grows slowly at 42 degrees Celsius. It also shows different growth patterns depending on the substance it’s grown on. If grown on Sabouraud agar, a substance commonly used to cultivate fungi, C. auris forms smooth, white to cream-colored colonies. On another substance called CHROMagar, C. auris colonies could have a range of colors from pale to dark pink and sometimes beige.

Risk Factors and Frequency for Candida auris

The Candida auris, a type of yeast infection, has different variations around the world. Experts have identified four distinct groups that are tied to different geographical areas: South Asia, East Asia, South Africa, and South America. There’s possibly a fifth group from Iran. However, the exact number of people affected globally is not clear because it often gets misdiagnosed due to its similarity to other types of Candida species.

First identified in Japan in 2009, Candida auris has spread across the globe, with cases emerging everywhere except Antarctica. A 15-year study revealed no signs of the infection before 2009. But more recent research found examples of this infection in South Korea in 1996, 2004, and 2006 and Pakistan in 2008, suggesting it may have existed earlier than initially thought.

By 2018, reports of infections from Candida auris had come from many parts of the world. These include various countries in North America, Europe, Asia, and Africa.

As of March 2020, according to the Center for Disease Control and Prevention, 41 countries have reported cases of Candida auris. The infection usually spreads in hospital settings, but there have also been isolated cases.

• In the U.S., there were 1092 cases as of March 2020, particularly prevalent in New York City, New Jersey, and Illinois.
• Most of the U.S. cases are thought to have resulted from foreign strains, linked to the South American and South Asian variations.
• Though these foreign strains were involved, most patients caught the infection in U.S. healthcare settings, indicating that the infection was spreading within these facilities.

Signs and Symptoms of Candida auris

Candida auris infection, a type of yeast infection, can present in a similar way to other yeast infections. This infection can be found in various parts of the body such as the nose, throat, lungs, heart, blood, liver, abdomen, rectum, urinary tract, vagina, bone, armpits, groin, wounds, pus, ear, and brain.

Usually, these yeast cells present on non-sterile parts of the body like the urinary tract, skin, and lungs indicate that it’s just present on the skin and not necessarily causing an infection. If you have any medical devices inserted in your body, such as a port or catheter, any redness, swelling, or discharge needs to be checked out.

C. auris infections can cause a variety of problems, including blood infections, heart infections, urinary tract infections, surgical wound infections, skin abscesses at catheter sites, ear infections, meningitis, and bone infections.

Unlike other yeasts, which usually live in the digestive tract, C. auris likes to live on the skin. It can form a layered biofilm, which thrives best under conditions similar to armpit skin. The yeast can be spread from one person to another, and people can become colonized with it a few hours to days after exposure. Infections can then follow within days to months after the yeast first colonizes the skin.

The risk factors for getting a C. auris infection are much like those for other yeast infections.

• Having a central venous catheter
• Having an indwelling urinary catheter
• Being immunosuppressed (for example, having HIV, blood cancers, solid tumors, being a recipient of a transplant, having low neutrophil count, or having had chemotherapy or corticosteroid therapy)
• Having diabetes
• Having chronic kidney disease
• Being exposed to broad-spectrum antibiotics or antifungal medicines within the last 30 days
• Having concurrent bacteremia or candiduria
• Receiving parenteral nutrition
• Having a blood transfusion
• Receiving hemodialysis
• Having surgery within the last 30 days
• Being admitted to the ICU

Testing for Candida auris

Checking for a Candida auris infection starts with taking a sample from the suspected area of infection. This could be a variety of places such as blood, urine, the nose or throat, lung mucus, chest cavity, heart, digestive fluid, belly fluid, stool, vagina, bone, underarm or groin area, wounds or surgery area, pus, ear, and brain or spine fluid. These samples are sent for tests to see if the infection is present.

It’s crucial to understand whether these samples show a real infection, especially if taken from areas of the body that are not sterile and might naturally have some Candida present. Usually, it takes 1 to 3 days for Candida species to grow in test systems, and another 1 to 2 days for it to be fully identified under lab conditions.

Identifying Candida auris is not always easy. It’s often mistaken for other Candida species due to similarities in appearance and behavior. Although certain physical characteristics of Candida auris can help clue in to its presence, these signs alone are not enough to confirm the diagnosis.

The most accurate form of identification uses a technology called Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS), which uses laser light to analyze the components of the Candida to accurately differentiate Candida auris from other species. Initially, this technology might misidentify Candida auris as another type of Candida based on its characteristics but once the Candida auris is added to the identification database, the labeling becomes accurate.

There are other molecular methods also in use based on sequencing certain regions of the ribosomal DNA. A rapid molecular test has been developed that can spot 15 different fungal pathogens, including Candida auris. This method is reliable and accurate, although it’s not available in all healthcare centers, which can make diagnosing and managing Candida auris challenging.

Additional molecular techniques, like Amplified Fragment Length Polymorphism (AFLP), are used to analyze Candida auris samples. AFLP has been particularly useful for mapping where different types of Candida auris are found around the world.

Treatment Options for Candida auris

One of the biggest challenges in handling invasive C. auris infections is its resistance to most anti-fungal drugs and its ability to develop resistance over time. Research shows a high percentage of C. auris strains are resistant to standard anti-fungal medications.

In a study in India involving 350 C.auris samples, 90% were resistant to azoles, a common type of antifungal drug. In addition, 8% were resistant to polyene (another type of antifungal), and 2% were resistant to echinocandins. About 25% of the samples were resistant to multiple antifungal drugs.

Early laboratory research shows promising results using a combination of two anti-fungal drugs, voriconazole and micafungin, for drug-resistant C. auris. However, the same success was not seen with other drug combinations.

Currently, there is no standard treatment for C. auris infection. Most cases are handled individually, guided by lab tests that match the C. auris strain to the most effective drug. Infectious disease specialists are highly recommended as consultants in these cases.

The US Centers for Disease Control and Prevention (CDC) suggests starting treatment with echinocandins (an antifungal group) until lab tests can identify the most effective drug. This is because many C. auris strains are resistant to other common antifungal drugs. C. auris treatment should only begin if the patient shows symptoms and should be avoided for patients carrying C. auris without any signs of illness.

Besides medication, management of C. auris also requires removing any central venous catheters or other internal devices as soon as possible. This is due to the risk of C. auris entering the body via these devices and causing infection. Patients with a blood infection should have their blood checked regularly and follow the recommended treatment.

Infections in the central nervous system or urinary tract might require different treatment due to the limitations of echinocandins in those areas. For instance, in urinary tract infections, the older antifungal drug amphotericin B may be used. And in central nervous system infections, amphotericin B and another antifungal, 5-flucytosine, are typically used, with changes made based on lab testing on the C. auris strain.

What else can Candida auris be?

When a doctor is trying to diagnose Candida auris, a type of fungal infection, they will need to consider other infections that might have similar symptoms:

• Other types of Candida infections, such as those by Candida albicans, Candida glabrata, Candida tropicalis, Candida paratropicalis, and Pichia kudriavzevii
• Aspergillosis, another type of fungal infection
• Bacterial sepsis, a serious body-wide infection
• Cryptococcosis, a disease caused by a specific type of fungus
• Septic shock, a severe infection that can cause organ failure

These are more common than Candida auris infection but Candida auris is found more often in people with weakened immune system. However, it can also infect healthy individuals. Simply looking at the symptoms isn’t enough to identify the specific type of Candida infection.

Certain characteristics of Candida auris, like the way it looks in a culture, its ability to survive in high heat (up to 42C), and salty conditions, can help doctors tell it apart from other types of Candida. However, these shouldn’t be the only methods used to identify the infection. Other methods, like molecular identification, are the standard way to confirm a diagnosis of Candida auris.

What to expect with Candida auris

Infections linked to C. auris, a type of fungus, have a rather high mortality rate when compared to infections from other types of Candida (a group of yeasts). The mortality rate due to C. auris infections can vary widely from 30% to 72%. The reason for this variation could be due to many factors like the severity of the infection, age, risk factors present, and other illnesses a person may have.

These infections can affect anyone from premature babies to the elderly. However, it’s been observed that children have a better chance of surviving these infections. Early detection of the Candida auris fungus and a quick start of suitable anti-fungal treatment can significantly increase the chances of survival.

Possible Complications When Diagnosed with Candida auris

The complications arising from an invasive Candida auris infection can differ based on the extent of the infection, the pre-existing health conditions of the patient, and the levels of resistance to treatment. Candida auris most frequently causes a bloodstream infection, known to the wider audience as a blood-borne disease. As the infection spreads, it may affect various organs, leading to their dysfunction. On the other hand, what starts as a localized infection may expand to become a widespread bloodstream infection and lead to severe outcomes including sepsis, a system-wide infection, and failure of multiple organs like the kidneys, heart, lungs, eyes, brain, liver, and spleen, and ultimately, in severe cases, death.

• Multiple organs dysfunction
• Sepsis
• System-wide infection
• Varied organ failures (kidneys, heart, lungs, eyes, brain, liver, spleen)
• In severe cases, death

Preventing Candida auris

Due to its high ability to spread and resistance to antifungal drugs, C. auris was labeled as a public danger by the Centers for Disease Control and Prevention (CDC). This fungal disease became a mandatory report in the US in 2016. The CDC has also provided guidance on how to control and prevent the spread of this infection.

In disciplining the spread of C. auris, clean hands are crucial. Health workers should always clean their hands as per existing protocols. They can use alcohol-based or chlorhexidine hand rubs when their hands are not visibly dirty. Gloves and gowns should also be worn, but gloves should never replace the need for hand cleanliness.

The strategies to control this infection have been adapted from the methods used to manage other types of infections and drug-resistant diseases that can easily spread within hospital settings. Actions to control the infection must be applied to anyone who is infected or carrying the infection, as both groups can potentially spread it.

In different healthcare facilities, precautions to prevent transmission are in place. Such measures include wearing gloves and gowns, placing a patient in a single room or with a group of patients who have the same infection, but not with those who have other drug-resistant diseases. Patients can be carriers of the C. auris infection for several months even after they’ve been treated, so it’s advised that they should be kept isolated for the duration of their hospital stay.

Patients who have been in hospital for a long time or reside in nursing homes might need to be screened for the infection three months following their most recent positive test and if they’ve stopped their antifungal treatment for at least a week. If the patient has had two negative tests for the infection a week apart, they can be released from isolation.

C. auris can survive on different surfaces in healthcare settings. Therefore, daily cleaning of a patient’s room and all care-receiving areas is paramount. Shared equipment must also be cleaned and disinfected thoroughly. Some disinfectants and ultraviolet light may not be effective against C. auris, but studies have shown promising results for sodium hypochlorite and hydrogen peroxide. Rooms cleaned with these two substances have proven to be effective in curbing the spread of the infection.