Last week in the media were many scary headlines about a new superbug causing infections in China. Some of the dramatic headlines included “antibiotic apocalypse,” “world on cusp of ‘post-antibiotic era,’” “new resistant superbug spreading.” These headlines came following a report in the Lancet Infectious Diseases journal about a new gene (MCR-1), detected in E.coli bacteria in pigs. This gene caused the E.coli to be resistant to an antibiotic called colistin. Very concerning was the fact that this gene could be spread from E. coli to other bacteria in the same class (gram negative bacteria).
Colistin is one of our oldest antibiotics in use today. It fell out of favor as we got better options, because of its association with severe adverse effects including kidney failure and toxicity to nerves. Because it is infrequently used, it is still very effective against most [gram negative] bacteria (bacteria cannot develop resistance against antibiotics that they have never been exposed to). It has traditionally been our last resort antibiotic, reserved for use when we have no other options.
When I read about the new findings in China, what I was most surprised about was the fact that they give colistin to their farm animals! I knew antibiotics were used in agriculture but I thought they were used only when animals were sick (naive me I suppose). It really did not click for me before, that farm animals are actually given antibiotics prophylactically, or “preventatively” to help them to gain weight quickly, so they can be taken to slaughter in a shorter time! And I would never have imagined that one of our most powerful antibiotics was the drug of choice! I have since come to realize, that most of the antibiotics sold in the Unites States are for use in food producing animals rather that in people. Imagine that! We talk about antibiotic abuse in people, and the fact that up to 50% of the time, antibiotics are prescribed incorrectly. But there is a whole other side to this antibiotic abuse situation; and that is it’s abuse in the agricultural sector.
Use of antibiotics in food producing animals results in antibiotic resistant bacteria thriving, and sensitive (susceptible) bacteria dying. Once the animal is slaughtered, the resistant bacteria on it’s carcass can be transmitted to humans and end up causing infection. I remember once I had a woman in her early 20s as a patient. She ended up in hospital with a urinary tract infection due to E. coli which was resistant to many antibiotics including some of our more powerful options. She had no medical problems at all and had never been admitted to hospital except to give birth to her child. I was puzzled that such a healthy person would get an infection with such a resistant bacteria.
It is very likely that she could have been exposed to that resistant bacteria from meat. She probably ingested the bacteria with her food and it remained in her gut/bowels (with the millions of other bacteria). It then managed to get from her stool into her urinary system and caused her infection. Because this bacteria was resistant to simple antibiotics that can be taken by mouth, this young woman had to miss work and be admitted to hospital to get an antibiotic via a drip. This demonstrates the inconvenience and higher cost of infections with resistant bacteria.
So… are we all going to start dropping like flies, from infection with drug resistant “superbugs?” I think not. From time to time, healthy persons, like the young lady described above, will get infections but most healthy persons are unlikely to die with these infections.
Who is at risk for serious infections with these “superbugs?” Persons with chronic medical conditions which weaken the immune system are at increased risk. These conditions include cancer on chemotherapy, rheumatologic problems such as rheumatoid arthritis and lupus requiring use of medications such as Humira, which can weaken the immune system, and persons who have had bone marrow or organ transplants.
Because these groups of people have weakened immune systems, they are more prone to infections and are therefore likely to be on antibiotics more frequently. The antibiotics kill a lot of the good bacteria in addition to the bad bacteria causing the infection. Resistant “superbugs” that the patient may have come into contact with are not killed by the antibiotics. They thrive and overgrow since there is no more competition from the other bacteria which are now dead. Eventually, actual infection may arise from these “superbugs.”
Another group of persons who are at increased risk for infections with superbugs are those with frequent contact with the healthcare system, such as kidney failure patients going three times per week for dialysis (they have relatively weaker immune systems as well), and patients who have had complexed surgeries such as joint replacements, and coronary artery bypass (for heart disease), for example. After these surgeries, a few follow up visits to the doctor are often needed, in addition to visits with physical therapists, and other healthcare providers. With each visit to a healthcare institution is the potential for exposure to bad bugs. Additionally, any surgery results in a break in integrity of the skin. That wound is a potential entry point for the bad bugs.
So what can one do to to decreased the risk of becoming infected with a resistant bacteria? Strive for optimal health (eat real food, exercise, minimize stress, don’t smoke cigarettes, control chronic medical conditions). Remember that hand washing is the cornerstone of infection prevention. Do not take antibiotics if you don’t need them. And, last but certainly not least, when preparing meat, properly wash and thoroughly cook it, to ensure that any (resistant) bacteria are eliminated. Don’t forget to wash your hands after handling the raw meat, and avoid cross contamination of shared surfaces with the raw meat. If at all possible (the cost may be prohibitive) buy meat from animals which were not given feed with antibiotics.
As for the MCR-1 gene and colistin resistant bacteria, no cases have been reported outside of China (and probably Malaysia) as yet. However given how easy it it to travel in the world nowadays, it is likely only a matter of time before that resistance gene becomes global.