Rampant misuse of antibiotics poses growing global threat, experts warn
Some days, Dr. Amesh Adalja finds himself in the 1930s.
That happens when a patient is infected with bacteria immune to antibiotics, the miracle drugs that transformed medical care more than 70 years ago.
“This infection is eventually going to consume you, and there isn’t anything left on the shelf to try,” Adalja, an associate at UPMC’s Center for Health Security, tells the person.
Overuse and misuse of antibiotics are pushing the world toward what Centers for Disease Control and Prevention Director Tom Frieden calls “a post-antibiotic era.” At least 2 million people in the United States contract antibiotic-resistant infections each year, 23,000 of whom die, the CDC estimates.
“No army in the world, no al-Qaida (cell), poses any kind of threat the way this does,” said Tom Sanderson, co-director of the Transnational Threats Project at the Center for Strategic and International Studies in Washington.
For the first time in history, more than half the world’s people live in cities, where disease spreads easily among the concentrated population. About 52 million people pack China’s Pearl River Delta, an area the size of Baltimore and Washington, which are home to just 6 million, Sanderson said. Antibiotic resistance in these environments is a “time bomb,” he said.
Widespread antibiotic use began in the 1940s, said Dr. Brad Spellberg, a medical professor at the University of California at Los Angeles and author of “Rising Plague: The Global Threat from Deadly Bacteria and Our Dwindling Arsenal to Fight Them.”
Before then, skin infections killed about one in 10 people, he said. Pneumonia killed about one in three. Doctors learned in medical school that they couldn’t change the course of an illness and their job was to accurately diagnose. For a time in the early 20th century, the most common prescription was for bourbon, Spellberg said.
“We have kind of forgotten how bad it was,” Spellberg said.
Antibiotics enabled cancer chemotherapy, complex surgery, organ transplantation and other modern medical practices, Spellberg said. Without them, cutting a patient or weakening his immune system knocks down natural defenses against bacteria, inviting deadly infection.
In a post-antibiotic era, “the average life span will go down about 20 years” to where it was in the 1930s, Spellberg said.
Too much of a good thing
On grocery shelves in Latin America, boxes of penicillin and amoxicillin stand beside bottles of Pepto-Bismol and other over-the-counter medicines. University of Pittsburgh professors sometimes bring back the boxes as a joke for Brian Potoski, a pharmacy professor and member of the UPMC Presbyterian antimicrobial management program.
“People are taking antibiotics for the common cold,” which is caused by a virus, not bacteria, Potoski said. “Antibiotics do absolutely nothing for a virus.”
Exposure to drugs designed to kill bacteria enables them to develop resistance. They reproduce hundreds of times a day, mutating. Some develop mutations that shield them from antibiotics. They survive while vulnerable bacteria die. Eventually, the bugs left are immune to treatment.
Most pneumonia in Hong Kong, one of the world’s largest and most-visited cities, no longer responds to antibiotics because of “rampant” overuse, Potoski said.
The United States uses about 30 million pounds of antibiotics in a year, 80 percent of which is used in agriculture, primarily to help livestock grow, Spellberg said.
Developing a drug can take 10 years — a glacial pace compared to bacteria’s Darwinian agility.
“We’re never going to win a war against bacteria,” Spellberg said.
Partly, it’s a numbers game. Bacteria outnumber people by 10 to the 22nd power (a 10 with 22 zeroes). Taken together, the world’s bacteria outweigh humans by 5,000 to one. A person’s body is home to more bacterial cells than human cells.
“We think we dominate the planet, but we don’t. Bacteria do,” Spellberg said. “Maybe the goal should be to achieve a peaceful coexistence — not seek to kill them, but disarm them.”
Back to the future
People didn’t invent antibiotics; they discovered them.
“Bacteria have been using these to attack each other for 2 billion years,” Spellberg said.
Biologists underlined that point in 2012 when they pulled from a cave bacteria that were resistant to 14 antibiotics. The cave had been isolated for at least 4 million years.
Researchers were working on tailored treatments, including bacteria-hunting viruses called bacteriophages, when Alexander Fleming discovered penicillin in 1929. A bacteriophage works on one kind of bacteria; penicillin wiped out most of them.
“You could just write a prescription, the patient would get better, and you didn’t have to worry about it,” Adalja said.
As the drugs lose effectiveness, researchers such as Dr. Ankit Mahadevia are returning to their predecessors’ approach. Mahadevia co-founded a Cambridge, Mass., startup, Spero Therapeutics, last year. It is developing a drug that flips a “genetic switch” in bacteria, making them less virulent and dangerous. It gives the host’s immune system time to fight the bug.
Because Spero’s treatment does not kill the bacteria, the bacteria won’t breed resistance as quickly, Mahadevia said.
“If it’s life or death, these bugs have a lot of incentive to develop resistance,” he said.
Though he’s among a minority of scientists working on such treatment, Mahadevia believes the field will grow.
“There are a number of groups that are starting to look at this,” he said. “There really is no choice. We just have to.”
Mike Wereschagin is a Trib Total Media staff writer. Reach him at 412-320-7900 or [email protected].