San Diego County has recorded 20 cases of a fungus threat that the CDC rates worrisome.

So far this year, San Diego County has already recorded 20 cases of candida auris, the drug-resistant yeast that the US Centers for Disease Control and Prevention warned this week is spreading “to an alarming rate in America’s medical facilities.”

First reported in 2016, nationwide infection totals have grown from 476 in 2019 to 1,471 in 2021, according to the CDC. Locally, there were three cases reported in 2020 and 9 in 2021, followed by a significant jump in 2022 with 60 cases identified, according to the county health department. The 20 cases reported locally from January to March mark a step that will exceed last year’s total.

Dr. John Bradley, medical director of the Division of Infectious Diseases at Rady Children’s Hospital, stressed Wednesday that this threat does not have the reach that the coronavirus has had during the pandemic.

Healthy people, whether adults or children, he explained, can fight the infection with little long-term consequence. Those who are at risk are those with weakened immune systems and, above all, those who have recently been treated with antibiotics.

Candida auris, he said, colonizes the body’s mucous membrane surfaces and typically only invades the bloodstream, causing a life-threatening infection in patients with diseases such as cancer, known to impair the body’s ability to fight infection. Bacteria are usually very good at killing off these yeast cells, and they are naturally present on mucous membranes. But antibiotic treatment kills off the bacteria, opening up a niche that auris can fill.

Unlike the coronavirus, Bradley points out, sharing the air with an infected person isn’t enough for auris to spread.

“It’s not airborne, you can’t get it just by talking to someone, you have to touch a surface and touch a mucous membrane, so healthcare workers can potentially spread it from patient to patient if they don’t wash their hands.” Bradley said.

It was unclear Wednesday how many local auris infections have been fatal, although the CDC says that based on limited information, 30 to 60 percent of infected people die.

Dr. Cameron Kaiser, deputy director of public health for San Diego County, said it’s hard to know for sure what to make of the increased detections of candida auris in the region. This particular strain may be detected more frequently because medical professionals look for it more often. And it could also be that other similar types of yeast were actually auris, but the tests didn’t tell them apart from their cousins.

“It’s quite possible that it was there all along, but now we’re starting to notice it more,” Kaiser said.

He added that it’s reasonable to assume that some of those confirmed to have a Candida auris infection died, but each of them would also have been battling other serious health problems.

The risk, he noted, is not limited to hospitals.

“Acute rehabilitation centers, long-term care facilities, skilled nursing facilities, all of these places are likely to house the type of people that candida auris poses a threat to,” Kaiser said.

The county routinely investigates reports of these types of infections, but Kaiser declined to say whether those investigations have found evidence of lax infection control practices. In general, he said, if evidence of serious infection control lapses were found, it would be referred to the state for possible regulatory action.

On the front lines, doctors are adopting a more aggressive mode of treatment.

Since Candida auris is resistant to first-line antibiotics, Bradley says the most important thing for health professionals is to look for possible bloodstream infections in patients at risk and move more quickly to more aggressive drugs, which cause more serious side effects.

“It’s a huge concern and we’re taking it seriously,” Bradley said.

Rady, he said, has yet to have a case of candida auris. But she said the hospital plans to test incoming patients, especially those transferring from other medical centers, to see if their mucous membranes have been colonized.

Bradley said auris can cause red swelling on mucous membranes, such as those in the mouth, but penetration into the bloodstream usually causes only an unexplained fever.