What You Need to Know About the Deadly Superbug Infection Resistant to All FDA-Approved Antibiotics

— -- The rise of drug-resistant bacterial superbugs has been a concern of public health officials for years, and now the U.S. Centers for Disease Control and Prevention has reported a worst-case scenario: a woman with a bacterial infection that was resistant to all FDA-approved treatments.

A Nevada woman died in September after being infected with a drug-resistant bacterium, Klebsiella pneumonaiae, that was resistant to all antibiotics available in the U.S., the CDC reported on Friday.

The woman was in her 70s when she arrived at a hospital in August 2016 with signs of sepsis. She had been in India years before and had been treated for a broken leg and bone infection, according to the CDC. After doing tests, her doctors found the bacteria — which belong to a class of drug-resistant bugs called carbapenem-resistant Enterobacteriaceae (CRE) — were resistant to all forms of FDA-approved antibiotics. The patient died in September after going into septic shock, according to the CDC.

The woman's extremely rare infection has focused attention on the increasing problems surrounding these drug-resistant infections and the lack of antibiotics available to treat them.

Fewer New Antibiotics Being Developed

No matter how effective an antibiotic is at killing bacteria, new drugs will be needed as the bacteria mutate and grow more resistant to existing drugs.

"Antibiotic resistance occurs as part of a natural evolution process. It can be significantly slowed but not stopped," the CDC notes on its website. "New antibiotics will always be needed to keep up with resistant bacteria as well as new diagnostic tests to track the development of resistance."

However, the number of drug applications for novel antibiotics being developed by pharmaceutical companies have been dropping steadily over the last three decades, according to the CDC.

From 1980 to 1984, there were nearly 20 FDA drug applications approved for new antibiotics, but from 2005 to 2009, there were fewer than five applications approved, according to the CDC.

In 2013 the CDC said developing antibiotics and diagnostic tests was one of its four core actions to stop antibiotic-resistant infections from increasing.

CRE Infections Are an Urgent Threat

In 2013 the CDC characterized CRE infections as an urgent threat, meaning the bacteria are an "immediate public health threat that requires urgent and aggressive action."

The bacteria cause 9,000 drug-resistant infections per year and 600 related deaths, according to the CDC.

While most CRE bacteria are still susceptible to one or more antibiotics, in the infection of the woman in her 70s reported by the CDC the bacteria were resistant to all FDA-approved antibiotics — an extremely rare case.

Common E. coli and Klebsiella bacteria are among CRE strains.

Doctors Can Attempt to Treat Even Drug-Resistant Infections

When a patient has a drug-resistant bacterial infection, doctors sometimes have to use harsher antibiotics or high doses in order to fight the infection.

If a patient has a drug-resistant infection, doctors work with a lab to test different doses of various antibiotics in an effort to overwhelm and kill the bacteria, said Dr. William Schaffner, an infectious-disease expert at Vanderbilt University Medical Center.

However, antibiotics can be taxing on patients, especially if they are older and have underlying medical conditions.

"This is the kind of calculation you do with every patient," Schaffner said. "Patients with underlying illnesses present a certain kind of challenge."

The CDC authors reported that an intravenous version of the antibiotic fosfomycin is available in other countries but is not approved for use in the U.S. It's unclear if the patient's doctors attempted to get an FDA exemption to use the drug and treat the patient.

Long Exposure to Antibiotics and Long Hospital Stays Can Be Dangerous

While this recently reported case is frightening, it is also unusual. The patient had been in and out of hospitals in India for two years after fracturing a femur and developing a bone infection.

Long hospitals stays, especially in India, and exposure to different antibiotics can increase the likelihood of eventually developing a drug-resistant bacterial infection. As travel around the globe is becoming more common, it's increasingly important for doctors to find out where their patients may have acquired an infection, Schaffner said.

"India has a notorious reputation for this [type of bacterium,]" he said. "Travel-related questions are becoming much more important ... and just reinforce that we are a very small world."