Last week, U.S. military researchers said they had identified the first patient in the United States to be infected with bacteria resistant to an antibiotic that was the last resort against drug-resistant germs. The patient has recovered, but the case raised the specter of superbugs that could cause untreatable infections.
The idea of people dying from infections once easily cured may seem outlandish. But it is happening — killing about 23,000 people in the United States a year — and experts warn that things will get worse because bacteria are becoming resistant to antibiotics faster than we can make drugs to fight back.
We have ourselves to blame, for overusing the drugs in people and squandering them on livestock. Now, a dangerous form of drug resistance has reached the United States, leaving us one step away from infections that are completely untreatable.
Q: What is antibiotic resistance?
A: It used to be infectious diseases were the biggest killers of Americans, illnesses such as tuberculosis and pneumonia. The invention of antibiotics, which were developed for medical use in the 1940s, changed that. But they became overused, and the bugs they were invented to fight started to develop ways of resisting them.
For some years, infectious-disease doctors have been warning that unless we rein in use of antibiotics in both people and livestock, there will come a day when they will be powerless against the most ferocious bugs, turning the clock back to the early years of the 20th century.
Q: What is CRE?
A: CRE, which stands for carbapenem-resistant Enterobacteriaceae, is the most fearsome family of germs because it is resistant even to last-resort antibiotics.
The only drug that reliably treats CRE is colistin, an old and inexpensive drug that came on the market more than 50 years ago. Last week, researchers reported they had discovered a gene in a bacteria that makes bugs resistant to colistin. It was found in a strain of E. coli in the urine of a patient in Pennsylvania.
The patient was successfully treated, but if that gene makes its way into a strain of CRE, the bug would be unstoppable. “We depend on colistin for the worst of the worst,” said Dr. James Johnson, a professor of medicine and an infectious-disease expert at the University of Minnesota. “If it is knocked out, in most cases we really have nothing.”
Q: How has antibiotic resistance changed medicine?
A: Johnson says the spread of resistant bugs means doctors are having to blast patients’ infections with increasingly stronger antibiotics. That has led to more patients coming in with infections caused by C. difficile, a gut germ that flourishes when the patient has taken a lot of antibiotics. (The germ was estimated to cause almost half a million infections in the United States in 2011, and 29,000 people died within 30 days of the initial diagnosis.)
Doctors now frequently send patients home with setups for intravenous antibiotics because pills no longer do the trick. Sometimes the specter of resistant infections can delay or cancel surgeries.
Q: Why aren’t there more new antibiotics?
A: Most drug companies are not eager to make them. Compared with other drugs, antibiotics are not big moneymakers, and some manufacturers have gotten out of the business.
Most people take antibiotics just once in a while, for a short time — unlike drugs for blood pressure, high cholesterol or diabetes, which most patients will take every day for the rest of their lives.
Infectious-disease experts are working with Congress and the Food and Drug Administration (FDA) to try to find ways to create financial incentives for drug companies to invest in Answers to tough questions about antibiotics, superbugs new antibiotics.
Q: Is there anything I can do to protect myself?
A: A few simple steps can help reduce your risk of picking up a dangerous bug, says Dr. Brad Spellberg, chief medical officer for Los Angeles County/USC Medical Center. Wash your hands frequently. If you get sick, try not to use antibiotics.
“What you should be doing is saying to the doctor, ‘Do I really need these antibiotics?’ ” he said.
Since hospitals are incubators of dangerous germs, if you end up in one, try to get out as fast as you can. As for whether to avoid meat raised with antibiotics, Spelling says there is some evidence that such meat is more likely to have resistant germs, but those are avoidable with proper cooking.
Q: Is there any real harm in taking an antibiotic for a cold?
A: There are several risks. An important one is based on the fact that healthy people normally carry billions of bacteria in their noses, throats, skin, genitals and gut. Antibiotics change the balance of those microbes, killing off susceptible ones and allowing drug-resistant ones to flourish.
Even after a person finishes a course of antibiotics, the excess of drug-resistant bacteria can persist for months. If those drug-resistant bacteria find their way into the urinary tract, they can cause a drug-resistant infection that may be difficult to treat.
In addition, people constantly pass bacteria to their close contacts, so they may put others at risk.
Q: Why are antibiotics given to livestock?
A: The vast majority of antibiotic use in the United States is in livestock — cows, pigs, chickens, sheep, even farmed fish — either for medical reasons, such as treating or preventing disease, or to promote growth. Most antibiotics used for humans are also used for livestock, said Dr. Karin Hoelzer, a veterinarian and microbiologist at the Pew Charitable Trusts who has studied antibiotic resistance.
Q: How can the use of antibiotics in animals pose a risk to humans?
A: There are several ways. The genes that produce resistance to antibiotics can be easily transferred between bacterial species. So resistant bacteria can pass their resistance to other strains.
Humans can come in contact with resistant bacteria through eating insufficiently cooked meat or other food products. Manure from animals fed antibiotics is commonly used as fertilizer for crops.
Farmworkers and people who work in slaughterhouses may also come in contact with the bacteria, providing an opportunity for genes to be exchanged.
Q: Have bacteria resistant to the antibiotic colistin been found elsewhere?
A: Colistin-resistant bacteria have been found in humans or livestock in countries on every continent, including China, Malaysia, South Africa, Egypt, Italy and several South American nations. Scientists have also reported finding colistin resistance in CRE in some countries, said James Spencer, a senior lecturer in microbiology at Bristol University in England. Spencer co-authored a 2015 study that reported for the first time the colistin-resistance gene in a form that could be easily transferred to other bacteria. The study looked at the presence of the gene in food animals in China.
Q: Has the FDA regulated the use of antibiotics in agriculture?
A: Under FDA policies that will take effect Jan. 1, antibiotics considered “medically important” for humans will no longer be approved for use to promote growth in livestock. The policies also require that a veterinarian supervise the use of antibiotics in feed or water for livestock. Many of the drugs are sold over the counter and do not require the involvement of a veterinarian.
Compliance is voluntary. But the 25 drug companies that manufacture about 283 antibiotics approved for use in livestock have all agreed to change their drug labels to reflect the requirements. Some critics, however, say they are concerned the new policies will leave loopholes that could allow food producers to circumvent them.