The Birth of Antibiotic Resistance
Posted by Richard Conniff on September 11, 2013
Rob Dunn at North Carolina State University recently asked me to write a sort of introduction to MRSA. Here’s the result, now live at the Invisible Life project:
One of the most tantalizing moments in medical history took place in February 1941, as a policeman named Albert Alexander struggled to fight off a devastating infection at an infirmary in Oxford, England. A few months earlier, puttering around his rose garden, he’d gotten a minor scratch on his face. It would have been just a scratch, nothing to bother about, except that Staphylococcus aureusbacteria infected the wound and gradually took over his body. Now he was “oozing pus everywhere.”
By good luck, Alexander had landed in the one place in the world where penicillin was being developed, and on February 12, 1941, he became the first human ever treated with the new antibiotic. His condition improved dramatically. But the new drug was so scarce the medical staff had to recycle it from the patient’s urine for reinjection. Then the penicillin ran out before the infection was completely gone. A month later, Alexander was dead.
To those of us who take antibiotics for granted, the idea of dying from a scratch may sound like a bad joke. But it was commonplace before World War II, and every mother lived in fear of losing her child to “blood poisoning.”
It was a hazard because bacteria, and particularly Staphylococcus aureus, are everywhere. About 20 percent of us are normally long-term carriers of some form of staph, as it’s commonly known, and about 60 percent of us carry it intermittently, usually on the skin and in the nostrils. It’s harmless most of the time. But it can also turn deadly in the event of an injury or an illness.
The ability of penicillin to fight off these staph infections was one reason antibiotics seemed like such an astonishing miracle as they became widely available in the aftermath of World War II. Doctors and hospitals were soon prescribing antibiotics for almost any illness, and patients used them with abandon, often failing to complete the full course of a prescription once their symptoms disappeared. The inevitable result was that antibiotics quickly killed off the susceptible bacteria and cleared the field for bacteria that happened to be resistant.
Penicillin-resistant strains of Staphylococcus aureus proliferated, and in 1959 a drug company responded with the new antibiotic methicillin. It was a backup line of defense, specifically designed to fight the bacteria that penicillin couldn’t touch. But methicillin-resistant Staphylococcus aureus (or MRSA) strains appeared just two years later, and soon spread through Western Europe, the United States, and the world.
Though methicillin itself is no longer used in patients, the name MRSA has persisted for staph strains that resist penicillin, oxacillin, ampicillin and other antibiotics. Staphylococcus aureus is by no means the only pathogen to develop antibiotic-resistant strains. Resistant Salmonella and E. coli, for instance, are also common and deadly. But MRSA is the most notorious of these so-called Superbugs.
The majority of MRSA outbreaks have always occurred in hospitals and nursing homes, where antibiotic use in humans is most heavily concentrated. But in the 1980s, community-associated MRSA also began to appear from skin-to-skin contact or use of shared equipment in locker rooms, military barracks, dormitories, and jails. More recently, livestock-associated MRSA has become an issue, because of the meat industry’s heavy reliance on antibiotics. A 2011 study in U.S. supermarkets found MRSA on 25 percent of meat samples, and some of those bacteria were resistant to as many as nine different antibiotics.
The symptoms of MRSA resemble any other staph infection: It begins with swelling and reddening of the skin around a wound, often with small red bumps like pimples. From there it can progress to a deep, painful abscess oozing pus, sometimes followed by infection of the bloodstream, which can then seed the lungs or heart with the infection. Treatment can involve draining the wound, keeping it clean and dry, and, if a test shows that it’s MRSA, administering a new or more potent antibiotic to which the bacteria has not yet become resistant.
Failure to recognize MRSA or take it seriously—for instance, by not completing the full course of a prescription– can be deadly. In 2005, MRSA was a factor in the deaths of 6639 people in the United States, more than half the 11,406 staph-related deaths that year. Since then, health care facilities have made serious efforts to control these infections, reducing incidence dramatically. But incidence of community-related infections has not significantly diminished.
MRSA also remains a serious concern because of the continuing danger that resistance will spread to the relatively few antibiotics on the market that remain effective, especially because there are few promising new antibiotics in the drug company pipeline. We stand on the brink of a “post-antibiotic era,” Margaret Chan, director general of the World Health Organization, recently warned. That could mean “an end to modern medicine as we know it. Things as common as strep throat or a child’s scratched knee could once again kill.”
And in Britain in 2010, this once-and-future peril became real for a 73-year-old patient named George Emmerson. He arrived at a hospital in Yorkshire with a rapidly spreading infection. Doctors amputated a finger, and then an arm. But nothing they could do, and none of the antibiotics they administered, stopped the infection from progressing to full-blown sepsis, or blood poisoning.
The cause of death? Like the policeman Albert Alexander almost 70 years earlier—and on the other side of the antibiotic revolution—Emmerson had gotten a trivial scratch while puttering in his rose garden.