Virtually everyone alive today has lived out their entire existence snugly within what Professor Jeremy Farrar, head of the United Kingdom’s largest medical research charity, terms the “golden age of antibiotics.” The hallmark of this golden age was the near eradication of infectious disease by products like penicillin. In a recent interview with the British Broadcasting Corporation, Farrar offered a grim forecast, predicting a creeping end to the rosy present at the hands of increasingly antibiotic resistant pathogens.
Penicillin, the first and most well-known of the world’s antibiotics, was discovered by Sir Alexander Fleming in 1928. In what is fondly regarded as perhaps the happiest accident in medical history, his discovery ushered in our current golden age. University of Wyoming microbiology professor Rachel Watson says Fleming discovered penicillin “by going on vacation.”
“He had a plate of Staphylococcus aureus [bacterium] that he had inoculated, and inadvertently a spore of Penicillium mold had landed on it” Watson elaborated.
Fleming returned from his vacation to find an enterprising colony of mold growing boldly in the midst of what should have been an uninterrupted carpet of bacteria. “His brilliance was recognizing that there was a zone of inhibition surrounding the growth of the mold” said Watson.
This zone – an area of the growth plate in which the bacteria could not survive – was due to a substance produced by the mold: penicillin. Once isolated and unlocked for synthetic production, penicillin came into widespread use and saved millions of lives. The later development of additional classes of antibiotics created what Watson calls a “magic bullet” impression in the collective consciousness: an impression which over the past 75 has proved detrimental.
“This is the holy grail, right?” asks Watson. “It’s like all we have to do is throw some penicillin at it. And that’s the root of misuse – it’s so easy to just prescribe antibiotics.”
Overuse and misuse of antibiotics has taken us from a point where penicillin was a cure-all, to a point where resistant infections take lives on a regular basis. By using these powerful medications so freely, healthcare providers and the agricultural industry have made a serious mistake – they have created an evolutionary environment that favors antibiotic resistance.
Bacteria are capable of evolving with absurd rapidity. They have a few tricks to help them with this: genetic variety, sheer numbers and rapid reproduction, among many others. An excellent case study for this is what happens when a person fails to finish their prescribed course of antibiotics.
Say “Tommy” has contracted a bacterial infection. Somewhere within Tommy there is a population of millions or billions of tiny bacteria somehow interfering with how his body ought to function. Tommy’s doctor gives him a course of ten penicillin pills and tells him to take all ten of them, one a day, over ten days.
Tommy takes his pills diligently for the first six days. The penicillin is working wonders; an incredible majority of the bacteria have no resistance to the penicillin and they die in droves. However, an infinitesimal percentage is resistant. Due to some pre-existing genetic difference, the penicillin doesn’t bother them.
Most of the penicillin-sensitive bacteria are dead on day six and Tommy feels much better. Because Tommy feels better, he decides he doesn’t need to finish his last four pills, leaving surviving bacteria in his system. While the overall number of bacteria has been diminished, antibiotic resistance is now much more prevalent in the remaining population. Furthermore, they are still too numerous for the immune system to handle alone. Now things get interesting.
The surviving bacteria begin to multiply as only microbes can. In a few more days, poor Tommy will be sick again. Only this time, when he takes penicillin, very little will happen as a large percentage of the surviving bacteria are not sensitive to the medication. Tommy has unwittingly bred a penicillin-resistant strain.
Watson stresses the importance of completing one’s prescription as directed, saying, “when you do finish your course of antibiotics, your immune system will clear up the few remaining resistant bacteria – because they do exist in the population. But if you don’t complete your prescription, then you’ve essentially put a selective pressure on them and they’ve succeeded in that selective environment. If you don’t finish the course, it creates an environment with a higher percentage of resistant cells.”
These same forces and concepts are at work with industrial and agricultural use of antibiotics, only the playing field is much larger. Landfills, agricultural runoff, and pharmacological waste all contain traces of antibiotics. In effect, humans have managed to create a nearly global pressure that drives bacteria toward resistance. Farrar’s warning is not the first, but it is one of the most direct and strongly stated. The end of the golden age, he says “will creep up on us almost without our noticing.” Unless, that is, science, policy and the public can cooperatively devise a solution.
