I’m not generally prone to fear, but two pages into Maryn McKenna’s Suberbug: The Fatal Menace of MRSA, a chill ran down my spine. McKenna opens her book with a story about a teenager named Tony who scraped his elbow after taking a tumble in the school gym. His elbow healed, but days later his left knee began to swell and throb. He developed a fever and body aches. Bay the time he was taken to a hospital, Tony was in septic shock. The ICU staff pumped him full of drugs and surgeons sliced through his body, draining infection from his hand, knee and thigh that reached all the way to the bone. “They told me he was the sickest child on that ICU,” his mother recalled. “They didn’t expect him to live.”
A healthy boy developing a life-threatening infection within a matter of days is scary scenario to imagine; even scarier is that vancomycin, the “drug of last resort” used to treat Tony’s infection, wasn’t killing the bacteria as quickly as they needed it to. And even more terrifying? The knowledge that strains of MRSA are already developing resistance to vancomycin. As imperfect of a tool the antibiotic is, we don’t have very many attractive alternatives at our disposal to fight bacterial infections of this potency, either.
So what kind of superbug was able to cause this level of damage to Tony’s otherwise healthy body? I had heard of “antibiotic resistance,” but hadn’t heard the term “methicillin-resistant Staphyloccocus aureus” (MRSA) before reading this book. Staph itself is quite common; roughly one-third of us carry it on our skin at any given time without it hurting us. MRSA is a particular strain that can invade surgical wounds and small cuts, causing infection that is difficult to treat with antibiotics. It has been resistant to penicillin for decades, and has become resistant to several other semi-synthetic penicillins that drug makers have created in the meantime. Our ability to develop and bring new antibiotics to market isn’t keeping pace with the bacterium’s ability to evolve and survive regardless of what it’s hit with.
As McKenna points out, our inability to match MRSA’s current rate of growth with drugs leaves us instead to explore ways to slow down the bacterium’s contagion and evolution. She identifies four spheres where the bug thrives: in hospitals, in sports facilities, in prisons, and on farms. The chapter covering this last sphere, ominously titled “Into the Food Chain,” also made me shiver.
Much of the book is set in the United States, but this chapter lends an interesting perspective as it explores how other countries are dealing with rising rates of MRSA. The Netherlands, which has had success controlling MRSA in hospital populations with its stringent “search and destroy” protocol, has also been proactive in its agricultural policy, banning the use of antibiotics in animal feed. McKenna traces the genesis of this policy, as Dutch doctors and scientists begin to identify a connection between MRSA on pigs and MRSA in humans.
In the 1950s it was discovered that continually feeding livestock small doses of antibiotics made them grow faster. Since then, it’s a practice that’s been used by farmers to increase margins and help maintain the health of animals confined in close quarters. As McKenna says, administering such small doses “kill off only vulnerable bacteria and leave the Darwinian battleground clear for the tough ones.” Concentrated animal feeding operations (CAFOs) are ripe ground for bacteria evolution, as are the manure lagoons they create. And MRSA has been found across the food system: on pigs brought to slaughter, in vegetables treated with manure fertilizer, and in samples of meat from butcher shops and supermarkets. The potential for cross-species transmission is unknown, as is the magnitude of consequences should this happen. What is fairly clear, however, is that the subtherapeutic use of antibiotics in livestock could seriously jeopardize our ability to treat human staph infections in the future. As Tara Smith, a microbiologist from the University of Iowa said, “It’s never a good thing to have a high percentage of a population colonized with MRSA, whether it’s animals or humans.”
One of the challenges public health campaigns addressing these issues are going to face is the level of scientific literacy needed to understand the problem. I’ve taken college-level biology classes but still found myself re-reading (or simply skimming over) some of McKenna’s microbiology-oriented passages. She nevertheless does an effective job conveying the complexity of the issue without dumbing it down, and offers enough human stories in between to remind us why this is important.
After reading Superbug I’m eager to learn more about agriculture’s contribution to antibiotic resistance. The 17-page chapter on the subject barely whetted my appetite, and left me with as many questions as it answered. It’s clear there are still many unknowns, particularly where our food chain is involved. This book helps lay a groundwork of understanding, which will be important for us to have as the issue of antibiotic resistance grows in urgency. This will likely happen far before any of us are ready for it.