Melissa Golden/The New York Times

Dr. Shawn Lockhart, a fungal disease specialist, holds a microscope slide with inactive Candida auris, in Atlanta, Aug. 23, 2018. The rise of Candida auris embodies a serious and growing public health threat: drug-resistant germs.

April 18, 2019

Resisting Drug Resistant Pathogens: The Fight Against Candida Auris

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As health systems worldwide battle drug-resistant pathogens, Cornell physicians and researchers are fighting against the mysterious and growing threat of Candida auris, a fungus that can cause fatal bloodstream, wound and ear infections.

As of February 28, 2019, the Center for Disease Control confirmed 587 cases of C. auris in the United States, over 300 of which are in New York State. Between 30 percent and 60 percent of people with C. auris have died, although other conditions may have played a role in these deaths.

People at elevated risk for fungal infections, including C. auris, include those with HIV/AIDs, organ transplants or cancer. Additionally, people who have received stem cell transplants, are hospitalized or are taking medications that weaken the immune system are susceptible.

Dr. Matthew McCarthy,  who treated C. auris patients at Weill Medical Center, cautioned against widespread panic about the infection.

“There’s fungi all around us, but they typically only infect people who have weakened immune systems – people who are already sick,” McCarthy told The Sun.

C. auris can be spread from person-to-person or through contact with contaminated equipment or surfaces, although the transmission mechanism is currently unknown. The C.D.C. has expressed concerned about C. auris because it has caused outbreaks in hospitals and nursing homes, is difficult to diagnose with standard laboratory equipment and is often resistant to multiple drugs.

“With fungi, there are just very few antifungal classes (types of antifungal medication) available, so when an organism becomes resistant to a major one, that’s a huge problem,” said Prof. Craig Altier, population medicine and diagnostic sciences, in an interview with The Sun.

The difficulty of developing antifungal drugs is in part due to similarities between human and fungal cells, making finding a drug that kills fungi without being toxic to people difficult.

“Almost all of the enzymes in fungi are similar to those in humans or animals,” said Altier.

McCarthy described some of the options for treating infections in immunocompromised patients.

“In some cases, patients have weakened immune systems, so you try to bolster their immune system. If someone is getting chemotherapy, you may have to hold their chemotherapy to treat an infection. You can give people infusions of granulocytes, which are white blood cells, to temporarily help their immune system,” McCarthy said.

McCarthy declined to comment on Weill Medical Center’s protocols for drug resistant pathogens and the actions they are currently taking to safeguard against C. auris, citing worries about misunderstandings by the public.

“If every hospital started reporting all the different superbug cases they had, it would make people very scared but wouldn’t convey that most cases are treated quite successfully,” McCarthy said.

The C.D.C. also does not tell the public the names of hospitals where drug-resistant pathogen cases are treated. Some patient rights groups take issue with the general policy of silence regarding drug-resistant pathogens.

Lisa McGiffert of the Patient Safety Action Network told The New York Times that “[Patients] might not get up and go to another hospital, but patients and their families have the right to know when they are at a hospital where an outbreak is occurring.”

C. auris is part of a larger health crisis of antimicrobial-resistant drugs. Overuse of antibiotics, antiviral and antifungal medications kill drug-susceptible pathogens while leaving antimicrobial drug resistant pathogens to grow and multiply. In the United States alone, 23,000 people die due to antibiotic-resistant infections each year.

To treat the issue of drug-resistant pathogens, the C.D.C. and the F.D.A. are working on prevention through education and policy change.

The C.D.C. website emphasizes that “antibiotics are not always the answer” because antibiotics do not treat viruses, are not needed to treat many common infections and their use contributes to the development of antibiotic-resistant bacteria. The C.D.C. is working with clinicians, patients and other health organizations to promote appropriate use of antibiotics and limit the rise of resistant pathogens.

It is not only humans who are over-prescribed for antibiotics; farm animals have, in the past, received medication to promote growth rather than to treat disease. The F.D.A. created the Veterinary Feed Directive in 2017, which requires that, if medically important antimicrobial drugs are to be used for production animals, they must be prescribed by a licensed veterinarian.

According to Altier, overprescription of antifungal drugs for people and animals is less of an issue than antibiotic overprescription. However, excessive use of antifungal drugs on agricultural crops may contribute to the emergence of drug resistant fungi.

Through collaboration between the private sector, the public, and medical professionals, Altier thinks we can resist drug resistant pathogens.

“This is all a shared responsibility. We are going to need to make new antibiotics and companies need to take that on. We also need doctors that prescribe antibiotics judiciously, and veterinarians who don’t overuse them on animals and people who don’t go to the doctor and ask for an antibiotic for a viral infection. We all need to work together on this,” Altier said.