Four people have died, and all antibiotics are ineffective: "Super fungus" is first seen in the United States spreading from person to person

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Source | the Scientist et al.

Compiled by Qi Yiyin

"Superbug" infections that are resistant to multiple antibiotics often occur in patients who have been treated with antibiotics. However, the United States recently reported the first cases of human-to-human transmission of "superbugs", indicating that such bacteria may have spread in American medical institutions.

The Centers for Disease Control and Prevention (CDC) announced on July 23 that earlier this year, drug-resistant Candida auris was found in patients in long-term care facilities and hospitals in Washington, D.C., and Texas, none of whom had received antifungal treatment. The cases in the two places occurred simultaneously and independently, but the patients in the same area had used the same medical facilities.

Multidrug resistance

Candida auris was first discovered in a patient's ear canal secretions in 2009, so its name comes from the Latin word for "ear", but it can also colonize various parts of the human body, including the nostrils, groin, armpits and rectum. Healthy people can carry this bacteria without symptoms, but if the body's immunity is weakened, it can invade the blood and wounds. People at highest risk of infection are those who are receiving care in nursing homes or medical institutions and have various catheters inserted into their bodies. The mortality rate of invasive infection with Candida auris is approximately between 30% and 60%. This data has a large uncertainty because the number of cases is small and many patients have more serious diseases themselves.

Candida auris is often multidrug resistant. The U.S. CDC divides antifungal drugs used to treat invasive infections into three categories: azoles, polyenes, and echinocandins. Currently, bacteria resistant to azoles and polyenes are relatively common, but only about 1% of infections are resistant to echinocandins. About a third of strains of Candida auris are resistant to two classes of antifungal drugs, and some strains are even resistant to all three classes of drugs.

Cases of C. auris infection in healthy individuals are still extremely rare, but it remains a serious threat to hospitalized patients. Because outbreaks of C. auris can easily occur in healthcare settings, it is important to quickly identify C. auris infection in hospitalized patients so that healthcare facilities can take specific prevention and isolation measures to prevent its spread.

However, Candida auris is difficult to identify using standard laboratory methods. It does not have easily recognizable phenotypic characteristics that distinguish it from other Candida species, which makes it difficult for medical institutions to intervene in a timely manner. Currently, the commonly used identification methods mainly include matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification and genome sequencing.

Urgent Threat

According to an announcement from the US CDC, pan-resistant Candida auris strains that are resistant to all three types of treatment have been discovered before, but the infected people were all patients who had received echinocandin drugs, while none of the patients discovered this year had received the drug.

According to the announcement, from January to April 2021, 101 cases of Candida auris infection were found in Washington, D.C., of which 3 people carried pan-resistant strains. They all suffered from other serious diseases and were treated in a long-term care facility. In Texas, 22 infections were found during the same period, of which 2 people carried pan-resistant strains and 5 people carried strains resistant to both echinocandins and fluconazole (a broad-spectrum azole antifungal drug). No epidemiological link has been found between the cases in the two places. According to The Dallas Morning News on July 23 local time, 4 patients infected with Candida auris in Texas have died.

“The concern is that the patients at risk are no longer limited to the small number of people who have already been infected and treated with medication,” Meghan Lyman, a co-author of the CDC bulletin, told The New York Times.

If infected with a pan-resistant strain, patients can only be treated with high-dose combinations of multiple antibiotics. "If you were to imagine a nightmare scenario of the spread of drug-resistant pathogens, this would be it," Cornelius Clancy, an infectious disease physician at the Pittsburgh Health Care System in Virginia, told the New York Times. "Untreatable fungal infections would pose a serious threat to immunocompromised organ transplant recipients and critically ill patients in intensive care units."

“We need to do a better job of surveillance and infection control, especially when grouping patients together,” says Michael Phillip, an epidemiologist at NYU/Langone Health. “We should definitely be concerned about C. auris, but we can’t lose sight of the bigger picture, because there are a lot of other resistant bacteria out there that we should be concerned about.”

Currently, the US CDC has listed five drug-resistant bacteria, including Candida auris, as urgent threats, and 11 bacteria as "serious threats." The COVID-19 pandemic will add more variables to the fight against drug-resistant bacteria: patients who are hospitalized due to COVID-19 and need to rely on ventilators to breathe are at a much higher risk of contracting drug-resistant bacteria.

References:

1. https://www.cdc.gov/mmwr/volumes/70/wr/mm7029a2.htm

2. https://www.the-scientist.com/news-opinion/cdc-warns-of-person-to-person-transmission-of-resistant-fungus-69019

3. Huashan infection experts take you to the auris, public account "Huashan infection"

https://mp.weixin.qq.com/s/kqTqsdIMYzVYtv4CnXc_sg

4. https://www.cdc.gov/drugresistance/solutions-initiative/stories/cdc-response-to-global-threat.html

5. https://www.cdc.gov/drugresistance/biggest-threats.html

6. https://www.dallasnews.com/news/public-health/2021/07/23/2-collin-county-hospitals-grapple-with-superbug-fungus-outbreaks-that-have-killed-4-officials-say/

This article is reproduced from the public account "Scientific Research Circle"