Over 220 cases of 'nightmare bacteria' were found in the US last year - here's why that's so terrifying

REUTERS/Fabrizio Bensch

An employee displays MRSA (Methicillin-resistant Staphylococcus aureus) bacteria strain inside a petri dish containing agar jelly for bacterial culture in a microbiological laboratory in Berlin March 1, 2008

• Antibiotic-resistant "superbugs" are spreading rapidly across the US, according to the Centers for Disease Control and Prevention.
• These germs contain antibiotic-resistant genes that can spread to other germs. Patients showing no symptoms can be unwitting vectors.
• Lab tests uncovered 221 cases in the US in 2017 alone.

"Nightmare bacteria" resistant to most antibiotics are popping up across the US, according to the Centers for Disease Control and Prevention.

Lab tests uncovered 221 cases of unusual antibiotic-resistant genes in bacteria across the US in 2017 alone, according to a CDC report.

Antibiotic-resistant bacteria are known as "superbugs." These superbugs can spread their genes to other bacteria as they constantly adapt to stay one step ahead of the antibiotics designed to target them.

AP Photo/CDC

This illustration made available by the Centers for Disease Control and Prevention shows the Shigella bacteria, a superbug that caused more than 200 illnesses in the US in 2015.

It's like a cat-and-mouse game on a microscopic scale.

Superbugs can spread rapidly as they constantly evolve to gain resistance to new forms of antibiotics, the CDC said.

Over one in ten people the CDC screened for the superbugs carried them, even when they showed no symptoms. These patients could act as unwitting vectors for spreading the germs if left untreated.

On top of that, 1 in 4 germs the CDC tested contained genes that allow them to spread antibiotic resistance to other germs.

"Once antibiotic resistance spreads, it is harder to control - like a wildfire," the CDC said in a report. These superbugs are responsible for the deaths of around 23,000 US residents each year, NBC News reports.

It's crucial to stop these superbugs from spreading as early as possible, and with aggressive measures. The CDC is developing a containment strategy to improve early identification of threatening superbugs, and direct patients to treatment.