The Centers for Disease Control and Prevention (CDC) can’t stop microbes from mutating and becoming resistant to even our strongest drugs. But it is working harder than ever to come up with an effective containment strategy to stop the spread of these lethal bacteria.

In 2017, the CDC’s Antibiotic Resistance Laboratory collected 5,776 “highly resistant” germs from all 50 states in the U.S. and Puerto Rico. Of these, 221 had evolved to carry a rare and formidable resistance gene. These are “nightmare bacteria”; bugs that are extremely difficult to treat, or can’t be treated at all.

Doctors have worried about them and predicted their development for years, as bacteria become accustomed to current generations of antibiotics.

As might be expected, the CDC is spooked by these bacteria. If they spread, as infections are want to do, the agency is tasked with stopping them, and that’s no easy task.

On April 3, CDC Principal Deputy Director Anne Schuchat announced the agency’s latest containment strategy, which recommends an aggressive response to the appearance of even a single case of drug-resistant infection. The germs usually appear in hospital settings, so the CDC says health care workers should be prepared to contain the drug-resistant microbes before they can travel beyond a hospital’s doors.

“When there’s a fire somebody needs to put it out,” said Schuchat.

At present, these “nightmare” germs are still rare and haven’t yet spread widely. But Schuchat said they’re still a threat.

“The bottom line is that resistance genes with the capacity to turn regular germs into nightmare bacteria have been introduced into many states,” Schuchat said.

Preparing hospitals everywhere to contain the spread of nightmarish pathogens is necessary because the failures of antibiotic drugs to treat these bacterial infections isn’t just a problem now. It will also be a problem in the future.

“With antibiotics, unlike other drugs, their efficacy goes down,” Eili Klein, an antimicrobial resistance researcher at John Hopkins Medicine, said in an interview. “Even the strongest penicillin from 50 years ago is less effective than it is now.”

Most, but not all, of highly-resistant bacteria are found in hospital settings, but if they get out, there might be little treatment recourse.

“The average person on the street is perhaps unaware of the clinical difficulty with resistant bacteria,” Shahriar Mobashery, a biochemist who researches antibiotic resistance at the University of Notre Dame, said in an interview.

“People assume that there’s always treatment,” he said. “But that’s not necessarily true. It’s not a fact that we can bank on.”

At the CDC announcement, Schuchat spoke about what effective containment looks like. She gave the example of medical workers at a nursing home in Iowa who found a patient suffering from a urinary tract infection with “unusual resistance.”

Curiously, the patient had not recently visited a hospital nor had surgery, and had spent years in the same nursing home. The bug, it seemed, may have come from inside the nursing home itself.

A containment team, wearing gloves and gowns, tested 30 other patients — none with symptoms — and found the germ had spread to five other people. Understanding exactly who carried the resistant bacteria allowed the health officials to contain the germ therein, said Schuchat. The rare bug never left the nursing home.

The CDC’s containment plans don’t rely upon any novel technologies; but they require vigilance. Health care workers must know how to identify resistant bugs, and any unusual germs must be promptly sent out to local or state testing labs. This may sound like simple, or even obvious protocols, but the CDC is taking it seriously. “Antibiotic-resistant germs can spread like wildfire,” their report reads.

The troubling irony here is that humanity is creating its own potential nightmare.

“The root of all resistance is the misuse of antibiotics,” said Klein. This means overexposing microbes, which can be quick to adapt, to our limited drug options. This is predominantly done through the misuse of antibiotics.

“Bacteria doesn’t distinguish between appropriate and inappropriate use,” said Klein. Both exposures add to bacterial resiliency, and in some cases, the creation of nightmarish superbugs.

“I’m assuming they’re calling it nightmare bacteria because these are the infections keeping people up at night,” said Klein. “Those nightmare scenarios where you can’t treat anybody.”