Maryn McKenna is the author of a new book called Superbug: The Fatal Menace of MRSA.
MRSA (Methicillin Resistant Staphyoloccus Aureus) kills more people every year than AIDS. In the US alone 19,000 die from it each year, and another 369,000 are hospitalized because of it. The World Health Organization calls MRSA the most important health issue of the 21st century.
I interviewed McKenna about her book and MRSA. You can read it below. You can also listen to the audio recording of my interview. I invite you to subscribe to a podcast feed (RSS, Subscribe in iTunes) of all my interviews with authors and other people, along with individual podcast episodes I find interesting. I'm using a service called Huffduffer to maintain the podcast feed — it's really cool.)
The following interview has been slightly edited for clarity.
Superbug is a really interesting book and it seems like it's becoming more and more timely. What makes MRSA so dangerous?
That question has a micro-answer and a macro-answer. The micro-answer is that MRSA (a lot of people just say "mersa") is a form of staph bacteria that have become resistant to almost all of the antibiotics that we use in medicine every day. It's been doing that over about 60 years, largely without our really noticing or understanding how big a threat it has become. It's a threat to people who are in hospitals, but in recent years it's also become a threat to people out in the everyday world. It kind of takes people by surprise. It often affects, for instance, people in gyms or kids who play sports.
The macro-answer is that MRSA is the leading edge of a really international epidemic of drug-resistant organisms that are getting worse and worse, both because they're getting more resistant and also because we've, for the most part, stopped making antibiotics. So as as the bugs get more resistant, were running out of ways to treat them, because there's no new drug coming along. And as if that weren't all bad enough, it takes in not just human medicine and how we use drugs there, but also increasingly how we use and misuse drugs in farming around the world.
How do people generally get MRSA?
It kind of depends on where you are. There are three overlapping epidemics that have happened in the last 50 years. The first was in hospitals. If you think about it, if you were a bacterium, then a hospital patient, especially a very sick hospital patient, would would be a pretty sweet target. Someone who is in an ICU, for instance, has a lot of breaks in the immune protection of their skin, because they've had surgery or have IVs or central lines plugged in. They are probably pretty debilitated. They're being given a lot of drugs that suppress their immune systems, and they are touched and visited by a lot of people who they can't get away from. There's a lot of opportunities to be infected. So people who are in hospitals tend to get infected by other people in hospitals or by hospital equipment. And those bugs are usually transferred from other people or from the equipment by healthcare workers.
The trickier part is that people also get MRSA in the real world. And the way that that happens is that the kind of bacterium that MRSA is — Staphylococcus aureus — is what's called a commensal — a bacterium that lives with us all the time. Probably a third of the population walks around any day with regular, drug-sensitive staph. It's on their skin, in their nostrils and other warm, damp, salty places on their bodies. Most of the time it doesn't make us sick. Probably about 1 1/2 or 2% of the population — about 5 million people — have MRSA on their bodies. It lives on our skin and doesn't really bother us until one of several things happens: maybe there is a kind of glitch in our particular immune system, maybe we get a scrape or cut the way somebody would if they play sports, or maybe we get a particular strain of the bacteria and it's particularly good at breaking through intact skin. That's how the community, the outside hospital cases, happen.
There's also a third kind of MRSA epidemic that has just emerged in the past couple of years, which has happened specifically in people who work with farm animals, mostly pigs. Pigs, it turns out, are carrying a strain of MRSA that sort of wandered into them and became resistant to the antibiotics that are used in farming (in addition to the regular human antibiotics) and then passed that back to farm workers and their families and to veterinarians. And in some countries in Europe that spread from there into healthcare workers and the general population, too.
Has MRSA been around for millions of years, or is it a result of less dangerous forms of staph adapting to overuse of antibiotics?
Photo of MSRA bacteria by Michael Taylor/Shutterstock
No one knows how long staph has been around. It was named back in the 19th century, but if you look at staph genetically, it has probably been around as long as we have. The reason microbiologists say that is because, of all the bacteria that are in close contact with humans, staph is uniquely good at developing workarounds for our immune systems. And it has so many different kinds of workarounds and protections that the hypothesis is that it's been living with us for a very, very long time.
MRSA, on the other hand, is a recent phenomenon, and it's really something we created. The first cases of MRSA were identified in England in 1961 and the reason that they're there is because staph had already become resistant to penicillin. Penicillin started being used in the 1940s. Staph very quickly became resistant to it. In 1960, in response to that, a drug company that existed at the time came out with a new drug, a kind of augmented penicillin, called methicillin. Methicillin is the "M" in MRSA. Staph became resistant to methicillin within 11 months of the drug coming on the market. The reason why we still use the acronym MRSA with "M" for methicillin is because the essential structure of methicillin is copied in dozens of other drugs that we now use and MRSA became resistant to all of those as well. But it really is sort of an unintended consequence of our drug development that staph became resistant to that drug and then to all those other related drugs across the years.
What is the current treatment for someone who comes down with an MRSA infection?
That's a really tricky question, for a couple of different reasons. First, because the bug is so diverse with those differences of cases happening in different settings, and second, because we're really running out of antibiotics. So if you are someone who gets an MRSA infection in the hospital — if you are an ICU patient or a burn unit patient — you're probably going to be really, really sick. You're probably going to get MRSA in a form that affects your blood, or the inside of your bones, or the valves of your heart. For those kind of infections there really only are one or two kinds of drugs that still work. And the particularly troubling thing is that of the three drugs that still work now — two are 50 years old. Only one of them is a really new drug.
On the other hand, if you get MRSA out in the everyday world because you picked it up from a gym bench or because you're a kid who picked it up from another kid in a football practice, what happens to you, or how you get treated, kind of depends on how the bug develops in your system. Some people only get abscesses — kind of walled-off collections of pus, and sometimes you don't even need use drugs for those. You just need to cut it open and let it drain. Some people get fairly minor infections of the skin, and there are older drugs that have never been used for staph before that we're starting to look at now that might be useful.
But there are people who, even with these outside world infections, get incredibly sick. The most common form is called necrotizing pneumonia where it gets into the lungs and pretty much melts them. And then you are reliant on those two or three remaining drugs that are running out of usefulness.
Are there any new treatments that are on the horizon that kind of take a different approach from antibiotics, that tap into the way people's natural immune systems work or anything like that?
People ask me a lot: "Are there botanicals you can use? Is there anything in herbal medicine?" And it's possible that for some of them, like minor skin infections, certain forms of medicinal honey for instance, might be effective. The problem is that none of these botanically based or herbal-based remedies have really been studied in any kind of scientific way. And what that means is that when you try to apply it as an individual person or even if you're a doctor out in the community who wants to try something there's no evidence for you to rely on so you're kind of in the dark and every person starts from zero.
Another really interesting thing that kind of got abandoned in the West but still hangs on in the countries of the former Soviet Union is something called phage therapy. Phages are viruses that affect bacteria. They're actually one of the vehicles for which bacteria become resistant because when those viruses infect bacteria they sometimes bring along with them DNA from other bacteria. Back in the former Soviet Union, from the 1930s to the 1950s and even 60s, people developed phage therapy as an alternative two Western antibiotics, because it's pretty low-tech and it's affordable. The problem is again, there's not much evidence. And it hasn't been systemized or industrialized in any way so every person's therapy has to be tuned to them individually. There are people in the US and Canada who have gone over on their own to the former Soviet Union, to the Republic of Georgia, for instance, and have sought out phage therapy on their own for really, really resistant infections that don't respond to drugs, and they report amazing success. But again, it is not something that's in any kind of system and so everybody has to undertake it for themselves.
Wow, that sounds like something we should look into, actually.
I think that the whole sort of "lost history" of phage therapy is so interesting. It was really getting somewhere right around the time that the Soviet Union collapsed and the whole scientific establishment of the Soviet Union was suddenly starved for money and broke apart. So possibly a great opportunity that was lost there and we need to go back and find those people who are still doing it, who are probably still in pretty poorly-resourced settings and give them a hand or partner with them or figure out what they're doing. Because even if it works in a sort of unpredictable way, or if it's a way that has to be tailored to individuals, we have so few other options now for the most resistant infections. I talk to doctors every week who tell me that they have had a patient in a medical center for whom literally nothing worked. It was, for them, essentially back to the pre-antibiotic era. And they have to tell families "I'm sorry, but here we are in the midst of this enormously technological medical center and I have nothing that can help your family member." It's stunning. It's something you can't believe could happen in the 21st century, and yet it does.
What's the best way to keep yourself safe from getting an MSRA infection?
That again has a two-part answer, because there are things we can do as individuals to keep it away from us and our families. Those solutions don't do anything to solve the larger problem, which is really a question of big institutional action. So what we do to protect ourselves? Staph and MRSA is a bacterium that lives on your skin. The Centers for Disease Control here in the US has identified certain situations in which you are more vulnerable to infection. They call them the four C's. And they are:
Lack of cleanliness. It's a good idea to wash your hands. And if you have somebody who's in a healthcare setting you should really harass the healthcare workers to make sure they are washing their hands. Health care workers aren't evil, they're not stupid, they don't intend to make people sick, but they have very technical and very demanding jobs, and it's very easy for them to get distracted.
Cleanliness also applies to some of the other seats in the four C's. Crowding makes you much more vulnerable. This is a bacterium that lives on skin. Your contact with other people's skin or in a setting where there's a lot of skin around can affect you. For instance, prisons and jails are now very crowded. There's a ton of MRSA in prisons and jails, which is a really troubling issue that I talk about in Superbug, and it hasn't received a lot of attention. It's particularly troubling because people in prisons and jails don't stay there. It's overcrowded and people cycle in and out a lot and bring MRSA back into their families and neighborhoods.
There's also skin-to-skin contact, that's another C, and that's especially important for athletes, both for professional athletes and student athletes. There have been really serious cases of MRSA and some of the major sports leagues. There are NFL players and basketball players who have effectively lost their careers over MRSA infections, and some of the most serious community infections have happened to kids who been playing football. They start practice in August, so it's hot. They might be wearing their pads at football practice but they might not be wearing tights and long jerseys and so forth. They crash into each other, and one gets scraped, and there you are.
The fourth thing is contaminated surfaces. That could be a surface someone has touched or someone who has MRSA on their skin. It applies to everything in a hospital — like the curtains in an emergency room cubicle, or the stethoscope, or the keyboard of the portable computers that they push in and out of hospital rooms. It also applies to things like the benches in the gym. Since I started reporting of this book a couple of years ago, I always wear long pants at the gym now. I never wear shorts. Because I worry that I might forget to wipe down the gym bench before I get on it with the dumbbells. And that's just my personal protective thing. So if you think about contaminated surfaces you think about cleanliness, your grandma was right, you should wash your hands a lot. That really does a lot to keep down the personal risk.