I just read an alarming piece on what the world will look like, possibly soon, when the efficacy of our current arsenal of antibiotics really starts to fade. There are already dozens of diseases that can resist some of the drugs we use to fight bacterial infections (antibiotics don’t work on viruses), and some can resist nearly all the drugs we have. But that is only the current state of affairs. The pace of antibiotic resistance is accelerating, as the bugs do a better job of evolving defenses against our drugs than we do coming up with new ones. We are rapidly moving toward a post antibiotics world. Among the risks we really ought to worry about, a lot, this one is near the top of the list.
The piece, Imagining the Post Antibiotics Future, is by my friend Maryn McKenna, one of the leading science journalists writing about this truly scary but overlooked threat. (Maryn also wrote the important book Superbug, the Fatal Menace of MRSA - multidrug resistant staph aureus) She summarizes how most of modern medicine depends on our ability to control infections. The list of what will become rare in a post antibiotics world is truly scary; most surgeries – of any kind, most medical treatments (like chemotherapy for cancer) that suppress the immune system, treatment of burns, kidney dialysis, hip and knee replacements and other prosthetic implants, implantation of cardiac or other medical devices, and treatment of all sorts of diseases in newborns, whose immune systems are not fully developed at birth.
We are living longer lives thanks to the way antibiotics have empowered modern medicine. If we run out of infection fighters that work, we literally could be looking at shortened average human life span. And don’t take the word of Ms. McKenna or me. Listen to what some of the top public health experts in the world say about this: (from Maryn’s piece)
“A post antibiotic era means, in effect, 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.”
Dr. Margaret Chan, Director General of the World health Organization.
Maryn notes that the chief medical officer of the United Kingdom, Dame Sally Davies, calls antibiotic resistance as serious a threat as terrorism , and published The Drugs Don’t Work. A Global Threat in which she foresees a world where infection is so dangerous that, as Maryn summarizes, “anyone with even minor symptoms would be locked in confinement until they recover or die. It is a dark vision, meant to disturb. But it may actually underplay what the loss of antibiotics would mean.”
So why, if the top medical authorities in the world take this so seriously that they are making such dire public warnings, are we not sufficiently worried? We get all up in arms about industrial chemicals and other environmental threats that are infinitesimal compared to the loss of antibiotics. We fret about fracking, and Fukushima and nuclear radiation. We demand legislation to protect us against people who text and drive. Where is the fear of this profound and imminent threat to your health and mine?
Well, this risk doesn’t ring a lot of the psychological alarm bells that make things feel scary. It doesn’t feel as imminent as, say, a possible terrorist attack, and risks that may happen down the road don’t worry us as much as the threats of the moment. This peril is abstract – an idea – which makes it more vague and less threatening than concrete risks like a plane crash or mass murder, which are personalized with actual human victims and real-world images. It is not associated with dying in a particularly dreadful way - with lots of pain and suffering - like our fear of anything that might cause cancer (which fuels our fear of many environmental threats).
And because it doesn’t ring many of the most important psychological risk perception alarm bells, the loss of effective antibiotics doesn’t get as much coverage in the news media, which is in business to get our attention, so they highlight news we’re more likely to pay attention to. So we aren’t aware of the risk, (or if we are, it’s kind of on the back burner behind all those other bogeymen), and psychologically, any risk that is more ‘available’ to our consciousness, …essentially the bigger brighter blips on our radar screen…is going to worry us more.
This is one of those truly frightening examples of what I write about, the Risk Perception Gap, when we worry too much, or too little, and the gap between our fears and the facts becomes a huge risk all by itself. So please, PLEASE, read Maryn’s piece. And please also read the chapter I wrote on this issue in my first book, RISK A Practical Guide for Deciding What’s Really Safe and What’s Really Dangerous in the World Around You, which I provide below, free. It describes the issue of antibiotic resistance in more detail. It will help you understand the problem. The statistics in that chapter may be a bit out of date. It’s ten years old. They‘re probably worse.
And please, please, share this with anyone you care about. This truly is a big threat to all of us, and it needs much more prominence on our risk radar screens. There is a race between bacteria and the medicines we use to control the harms some of those bugs do, and the bugs are winning. Losing has truly dire consequences.
When penicillin became commonly available in 1941, it was widely believed to be the wonder drug that would keep people safe from all sorts of bacterial infections. It looked like we had won the war on germs. Hardly. Within two years, doctors began reporting cases of a common bacterium, Staphylococcus aureus, which somehow could resist the effects of penicillin. Almost as soon as antibiotics became available, bacteria began developing ways to resist them.
We are in a race, between the development of new and more effective antibiotics, and the ability of bacteria to adapt in ways that defeat those drugs. Many experts say the bacteria are winning.
Here’s the problem. Microbes like bacteria produce a wide variety of chemicals, some of which kill or impair competitors. When we identify those chemicals and synthesize them into drugs, they become antibiotics. Penicillin, for example, is based on a secretion from the mold Pencillium notatum that kills bacteria by destroying their ability to build a cell wall.
But the bacteria want to protect themselves. Whether those chemicals come from neighboring bacteria or from human-made drugs, bacteria are always evolving new ways to fight off those chemicals. They have a fantastic ability to mutate, to form new versions of themselves, and sometimes the mutations help them resist the effects of the antibiotics.
Even one single bacterium that finds a way of fighting off antibiotics has a survival advantage over other cells of the same species that don’t have the resistance trait. When we take antibiotics for that germ, the cells with resistance survive, and the ones without it die. Then, with the weaker competitors gone, the surviving resistant bacteria cells thrive and multiply, passing the resistance trait on to their offspring. They become the variation of the species that survives over time, and our drugs lose their effectiveness.
Bacteria can accomplish these mutations in several ways. They can actually swap parts of their DNA between species. So a resistance trait that arises in one bacterium can quickly be passed to other types. Also, bacteria are prolific reproducers. A single bacterium cell in an optimal growing environment can produce as many as 68,719,476,736 copies of itself in just 12 hours! On average, about one in every million times a cell divides and passes its DNA on to its offspring, something goes wrong and a mutation occurs. So a single bacterium cell can undergo tens of thousands of mutations in just a matter of hours! If one of those mutations creates a trait that helps fight off an antibiotic, the drug that used to work on that germ either won’t work as well, or it might not work at all. And remember, bacteria can swap pieces of DNA between species. So this new resistance trait in germ A can start showing up in Germs B, C, D, and so on.
But the bacteria are getting help, from us. The widespread overuse, and misuse, of the antibiotics that are supposed to keep us healthy, accelerates the process.
How? Let’s say you get an ear infection and take amoxicillin, an antibiotic commonly prescribed for that malady. The drug should work. But if even just one cell of the ear infection germs has mutated and developed a resistance trait, it will survive. And if that bacterium has shared its resistance trait DNA with other species of bacteria, they’ll survive too. And they’ll flourish, because the drug has killed off the “weak” germs, which are no longer around to compete for food and resources. So the resistant strains proliferate and pass their resistance traits to their own offspring, or share their resistance genes with yet other bacteria. As antibiotics kill off the bacteria they work on, they increase the likelihood of new strains that can resist them.
In most developed countries, people take far more antibiotics than we need. In the United States, between 160 and 260 million prescriptions for antibiotics are written each year. But experts say that between one third and one half of these prescriptions are unnecessary. They’re prescribed to people who have viral infections. Antibiotics don’t kill viruses. But when we’re sick, we want “the pill” that will make us better. Most doctors acknowledge they prescribe antibiotics to patients simply because the patients demand them.
Now remember what we said a moment ago. Every use of antibiotics encourages the growth of resistant strains. So the massive mis-prescribed use of antibiotics in America contributes to the problem. (By the way, it is potentially worse in many countries overseas, where you can get many antibiotics over the counter, without a prescription.)
We’re helping the germs in other ways too. Let’s say we’re supposed to take our prescription antibiotics for, say, ten days, but we feel better after five. We stop taking the drug. We’ve killed the weaker germs in the first few days, enough so we feel better. But stronger bacteria that have even a partial ability to resist the drug might have survived. The full ten days of the medicine would have killed them off. Instead, these slightly more resistant bacteria survive, and spread the resistance trait that helped them fight off the first few days of the drug.
And that’s not all. Another way we’re helping the bacteria is, believe it or not, in hospitals. Think of this one as the ‘shotgun’ approach. Broad-spectrum antibiotics, which kill several different kinds of germs, are commonly used in hospitals, even when a more targeted drug that only kills the specific bacterium causing the illness would be enough. Yes, that increases the likelihood the patient will get better. But broad-spectrum drugs kill off more weak species of bacteria, eliminating the competition for the resistant strains that are left behind.
Yet another way that humans are accelerating antimicrobial resistance is the use of antibiotics in farm animals. As much as half of all the antibiotics produced for use in the United States are used on farm animals, mostly at low doses over a long period, to keep the animals healthy and encourage growth. But the low doses allow resistant strains of bacteria to out-survive the weaker ones in cows and chickens and other animals produced for food. Some of these resistant bacteria, like strains of salmonella, shigella, and E. Coli, can get into us if we don’t handle and prepare our foods carefully. Then, when we get sick, the strains of the bacteria we got from our food already have the ability to resist the drugs that used to control them.
We also make it easier for bacteria to swap their resistance traits with other species, in places like schools, hospitals, and chronic care facilities, places with a concentration of people with less effective immune systems, like young kids, the sick, or the elderly. There are often more bacteria, and more different kinds of bacteria, in people with weaker immune systems. Not enough to make them sick. But enough to increase the chances that one of them might develop a resistance trait, and share it with other species.
Finally, our globally connected world helps spread microbes as fast as planes can take us from one place to another, or ships can carry products from one continent to another. Two recent examples are SARS and West Nile virus. They got from Asia and the Middle East, respectively, to North America, on airplanes.. In essence, people and our global transportation systems serve as vectors – carriers and spreaders - of bacteria. The more interconnected we are, the easier it is for the resistant species to hitch a ride and spread around the world.
The Range of Consequences
So what does all mean to you? In general, antibiotic resistance raises the likelihood that if you get a bacterial infection, you’ll be sicker or stay sick longer or that you could die from an infection that used to be treatable. It raises the risk of death even more if you have a weaker immune system, less internal ability to help fight the infection.
How much greater is your risk? Unfortunately, it’s hard to translate this risk into numbers of victims. Sometimes the antibiotics fail outright. Those victims are more readily identifiable. But sometimes the drugs just don’t work quite as well as they used to, and a patient gets sicker or stays sick longer, but then recovers. Experts have no way to track those sorts of cases. And often these effects occur outside a hospital, nursing home, or other facility where accurate surveillance records can be kept.
But a pattern of chilling statistics comes from a number of sources.
Staphylococcus aureus demonstrates the threat of antibiotic resistance frighteningly well. Staph aureus is a common bacterium. Most of us carry it in our noses or on our skin. It can cause minor infections or life-threatening diseases like pneumonia. Penicillin used to kill it. But in the 1950’s, less than 10 years after penicillin hit the market, Staph aureus had become so resistant to penicillin that healthy people going to hospitals got sick and died. Many hospital maternity wards had to close.
So drug companies developed methicillin in the 1960’s. It worked, at first. Now, the CDC estimates that as many as 80,000 people a year get a methicillin-resistant Staph aureus infection after they enter the hospital.
So doctors switched to the antibiotic vancomycin, a broad-spectrum drug widely thought of as the antibiotic of last resort. In 1997, the first cases of vancomycin-resistant Staph aureus showed up in three geographically separate locations. Many more have since been reported. In 2000, the first revolutionary new type of antibiotic to come out in 30 years, linezolid, was approved, offering hope in the fight against Staph aureus and other multi-drug resistant bacteria. It took less than a year for the first cases of linezolid-resistant Staph aureus to show up.
Here’s are some other sobering facts
- According to the CDC, Streptococcus pnuemoniae annually causes
100,000-135,000 hospitalizations for pneumonia, 6 million ear infections, and more than 60,00 cases of other invasive diseases, including 3,300 cases of meningitis. The CDC estimates that at least 40 percent of these cases are caused by drug resistant strains of S. pneumoniae.
- Between 1993 and 1998, 45 states and the District of Columbia reported
at least one case of tuberculosis that was multi-drug resistant. Health officials once thought tuberculosis had been all but wiped out in the U.S. Resistant strains are bringing it back in several major cities.
- The CDC estimates that 2 million people a year get infections after they
enter the hospital, what are called nosocomial infections. Experts think that a significant number these fatal nosocomial infections are caused by drug resistant bacteria. Approximately 90,000 of these people will die because of these infections.
- Between 1979 and 1987, only .02 percent of the pneumococcus strains
infecting patients in 13 hospitals in 12 states sampled by the CDC were penicillin-resistant. By 1994, that number had risen to 6.6 percent.
- In a 1999 nationwide sampling of food borne bacteria by the National
Antimicrobial Resistance Monitoring system (NARMS);
- 26 percent of the non-Typhimurium Salmonella samples were resistant to one or more antibiotics. 49 percent of the Salmonella Typhimurium samples resisted one or more drugs.
- 91 percent of the Shigella samples resisted one or more drugs.
- 10 percent of the E.coli samples resisted one or more antibiotic.
- 53 percent of the Campylobacter samples were resistant to one or more antibiotic.
- Food borne disease outbreaks are often caused by drug-resistant
strains of bacteria.
- In 1998, 5,000 people in America fell ill from Campylobacter caused by contaminated chicken. The strains of bacteria found in the victims were resistant to several antibiotics.
- In 1968, 12,500 people in Guatemala died in an epidemic of Shigella-caused diarrhea, from a strain of the bacterium that was resistant to four antibiotics.
- A deadly drug resistant strain of Salmonella named DT104, more virulent than other strains, appeared in the late 90’s. It has killed people in Great Britain. 28 percent of the Salmonella Typhimurium samples tested by NARMS in 1999 had traits similar to DT104. (The Food and Drug Administration has approved a test kit for rapid detection of DT104.)
- Overseas, nearly every case of gonorrhea in Southeast Asia are
- In 1990, cholera bacteria in India were susceptible to common
antibiotics. Just ten years later, none of those drugs worked on cholera anymore.
- Our global world is helping spread some of these strains far and wide.
- Between 30,000 and 80,000 U.S. travelers returning from overseas suffer from a bacterial-caused diarrhea that is drug resistant.
- 2,500 travelers a year return with malaria that could not be prevented by prophylactic antibiotics that used to work.
- Investigators have documented the migration of one strain of multi-drug resistant Strep. Pneumoniae from Spain to the U.K., the U.S., South Africa, and elsewhere. Two cases of multi-drug resistant Staph. aureus in the U.S. were traced to Northern India. Most of the multi-drug resistant strains of typhoid found all over the world have been traced to six developing nations.
- Remember vancomycin, the antibiotic of last resort? Vancomycin-resistant enterococci, a normally harmless bacterium that lives in the human gut, were first detected in France and England in 1987. Then one appeared in New York in 1989. By 1993, 14 percent of patients in intensive care units in the U.S. had vancomycin-resistant enterococcus, a 20-fold increase in 6 years. Given the ready swapping of genes between different species of bacteria, the ability to resist vancomycin could easily spread from enterococcus to other more harmful species.
One top U.S. health official put the risk this way. The ultimate consequence from the growing problem of antibiotic resistance “…could be a return to the days before antibiotics, when common diseases were often lethal.” “ We are skating on the edge of the ice,” he said.
Where Are You Exposed
We are exposed to bacteria everywhere, all the time. Inside, outside, and on every surface or product that hands can touch or people can breathe or sneeze or cough on. One particular environment health officials are worried about is hospitals and nursing homes, where a combination of factors raises the likelihood of exposure.
- A significant number of people who are hospitalized come in with weakened immune systems or undergo treatments such as chemotherapy, which impair their immune response. These people are at risk of more serious illness, or death, from infections that neither they nor drugs can fight.
- A significant percentage of people who are hospitalized are elderly, with immune systems compromised simply by age. (This is one reason why exposure to drug resistant bacteria is also a concern in nursing homes and assisted-living facilities.)
- Surgical patients are more susceptible to any kind of bacterial infection simply because their skin has been opened.
- Open wounds, or healing wounds, are another potential route of nosocomial infection.
- Inadequate hygiene by people who work in hospitals, from visitors to food service personnel up to nurses and doctors and surgeons – even something as simple as not washing their hands thoroughly and regularly – helps spread drug resistant strains of bacteria.
Another setting where exposure to drug resistant bacteria is a concern is day care centers, especially for infants. Here, a combination of children with still-developing immune systems, lots of direct contact between children and their care givers, and an environment where one or two people are frequently sick at any given time, increases the chances of spread of bacteria, accelerating the spread of resistance traits.
People at higher risk
We have thousands of different strains of bacteria in us all the time. They play a vital role in many healthy bodily functions. When a species gets into our system that could be harmful, most of the time our own immune system identifies the invader and kills it. But, as mentioned above, people with weakened immune systems are at greater risk. These include people already ill from something else, infants with still-developing immune systems, people taking steroidal medication, people on dialysis, people on chemotherapy, and the elderly, whose immune systems are no longer as effective as they used to be.
What You Can Do
As frightening as this risk may seem, there are several steps you can take to protect yourself and help slow the proliferation of antibiotic resistant bacteria.
- Don’t demand antibiotics any time you get sick. Remember, between one third and one half of antibiotics are mis-prescribed to patients who don’t really need them. Don’t automatically demand antibiotics for your children if they have what appears to be an ear infection. Medical authorities now think that mild cases may go away by themselves. And they say that not all ear infections are bacterial.
- Pay attention to simple hygiene. Cover your nose and mouth when you sneeze, to avoid spreading germs. And cover it with the inside of your elbow, not your hands. If the person who just went in the door ahead of you recently sneezed or coughed into her hands and then touched the door handle, that handle is teeming with germs ready to get at you as soon as you touch it. Wash your hands frequently, vigorously, with soap and water if possible, especially after trips to the bathroom.
- In the kitchen, wash fruit and vegetables thoroughly. Cook meat, chicken pork, and fish well enough to kill bacteria in the meat. 145 degrees for steaks, 160 degrees for ground beef, 170 degrees for white meat chicken or turkey, and 180 degrees for the dark meat. Meat thermometers can help. (This is why a growing number of restaurants have a disclaimer on their menus that it’s not their fault if you order something undercooked and get sick. One hamburger place in San Francisco refused to serve rare burgers at all.) And don’t forget the same thing applies to leftovers. (See more in the chapter on Food Poisoning.)
Also, use good sanitation when preparing foods. The germs in a piece of meat that you prepared on your kitchen counter might be killed when cooked. But cooking won’t kill the germs still on the counter as you prepare your salad. So wash your food preparation areas each time you finish working on one part of a meal. Bacteria thrive in sponges. Throw them out or put them in the dishwasher or hot water.
- No surprise, but diapers are a source of bacteria. People handling diapers should be extra vigilant about washing their hands afterwards.
- Follow the instructions for taking antibiotics. Don’t stop taking them just because you feel better. Some of the bacteria with the ability to resist the first few days of the drug may still be alive in you, ready to pass on their resistance traits. Finishing the full course of the medication will help finish off many of these slightly stronger germs.
- Keep yourself healthy. Maintaining a good diet and getting half an hour of mildly aerobic exercise at least a few times a week, are simple steps to build up your body’s own systems for fighting germs.
For More Information
The Centers for Disease Control has a good website with basic information on this issue, and links to other sources.
This chapter was reviewed by:
Marc Lipsitch, Assistant Professor of Epidemiology at the Harvard School of Public Health, who has done research on antibiotic resistance, and by Dr. Don Goldman, Epidemiologist at The Children’s Hospital, Boston.