At a recent social event, I met an alum of my business school working in marketing for a pharma outfit that makes a “last-ditch” antibiotic – a powerful weapon against bacterial infection that hospitals and doctors keep in close reserve lest careless overuse breed resistance by bacteria. “Oh,” I said, “I’ve heard of your product; it’s our weapon of last resort.” I meant it as a compliment, but he was annoyed. He replied that he hoped vigorous “education” of physicians would lead to its increasing use as a first-line agent. I was taken aback – what did he expect would happen if resistance to his agent developed, which it inevitably would?
The plagues of yesteryear have nothing on today’s bacteria. Yersinia pestis, causative agent of the bubonic plague and scourge of Europe, would at least have succumbed to such simple drugs as doxycycline and gentamicin, if we’d had them. But modern-day hospital plagues, which boast astonishing armaments of antibiotic resistance, would not give in nearly so easily.
Fig. 1 - These bad eggs are harder to recall
The past century has seen wave after wave of antibiotics rising to the fray since Alexander Fleming first discovered penicillin growing out of mold in his jacket. The beta-lactam class, most famed for its use against the Gram-positive Staphylococcus, Streptococcus, and Enterococcus genera, has evolved from humble penicillin to modifications like nafcillin and oxacillin, then to “augmented” beta-lactams like amoxicillin-clavulanate. The related cephalosporin class followed with five successive generations of increasingly broad-spectrum agents. Vancomycin, not a beta-lactam relative but also key in the fight against Staph, was more recently added and remains a crucial jack up our sleeve. The cephalosporins were more recently succeeded by the expensive and powerful carbapenem class. Imipenem, ertapenem, and meropenem are the F-22s of the hospital world – support forces enlisted only when the beta-lactams, cephalosporins, and even the vaunted Vancomycin have been bested. Finally, in secretive reserve are kept an array of strangely-named shock troops – daptomycin, tigecycline, linezolid, polymyxin – an arsenal whose deployment is spoken of with some awe by housestaff for the degree of desperation that it signals.
Yet Staphylococcus and its ilk have kept pace with us every step of the way. Bacterial resistance to antibiotics turns out to be all the proof Darwin ever needed. Each infection, each asymptomatic carrier, and each dirty hospital surface is a tiny ecosystem where the laws of evolution play out on a grand scale with incredible speed. Every time a population of bacteria is confronted with an antibiotic, those chosen few in the teeming biofilm graced with chance mutations that confer resistance survive, while their weaker peers perish. In the aftermath of the microbial holocaust, with now-unfettered access to nutrients and surfaces, the hardy survivors flourish. Quite literally, that which does not kill them makes them stronger. Since bacterial generations come and go in mere hours, even slight advantages transform into entirely new resistance mechanisms very quickly. What’s more, bacteria do not wait for Prometheus to bring them mutations – they transfer them rapidly to one another on extra-chromosomal DNA elements called plasmids, which can amass multiple resistance genes and even pass between species.
The result has been MRSA, methicillin-resistant Staphylcoccus aureus, the dreaded leading cause of flesh-eating infections; VRE, Vancomycin-resistant Enterococcus; and ESBL (extended spectrum beta-lactamase)-producing Klebsiella. In recent years, we have even see the rare VRSA, or Vancomycin-resistant Staph aureus, and novel foes like producers of KPC (Klebsiella pneumonia carbapenemase), a deadly tool that grants immunity even against carbapenems. The Infectious Diseases specialists, the tight hand on the spigot of Vancomycin and other advanced drugs, are the last bastion against the indefatigable march of antibiotic profligacy and thus bacterial resistance. Every doctor wants to use just a little more antibiotic than they need; every such use strengthens bacteria just a little more. But even the ID docs have found themselves forced to dole out the big guns with increasing regularity. It is a typical academic ICU that sees multiple patients on contact isolation and at least some receiving daptomycin or linezolid. The enemy is gaining ground.
In classic American fashion, private industry has come to the rescue. Where antibiotics were once a dead-end for drug development, in the last decade a few specialty pharma shops have forecast big bucks ahead. Some thorny ethical questions arise. On the one hand, our patients desperately need new antibiotics. Recognizing the relentless advance of the super-resistant organisms, the Infectious Diseases Society of America has called for 10 new drugs by 2020.
On the other hand, there are audible overtones of opportunism and cynicism. It’s common to see advertisements like this one for tigecycline, depicting a doctor with a vigilant tiger at his side, on the webpage of the New England Journal of Medicine or on docs’ ID card lanyards. These ads are not-so-subtly intended to nudge more and more overuse of potent antibiotics. The marketer I met himself admitted that his company’s strategy was to encourage overuse, replying to my question with confidence that his company’s next products would replace its current one when – not if – resistance develops. How convenient, I thought – a product whose use creates a market for the next product.
Fig. 2 - Med schools had begun to admit more and more magicians
In miniature, the story of antibiotic resistance mimics the story of the American economic collapse. In a classic Tragedy of the Commons, every participant seeks to get as much personal benefit as they can, deferring the costs or trying to pass them to others – with the economy, it was derivatives; with medicine, it is our temptation to use more powerful drugs than we need. As we run out of places to hide, we need someone to save us from our own excess – with the economy, it was the Bailout; with medicine, it will be these costly new drugs. But questions will linger. Are our saviors truly White Knights who care only for discovering cures, or are they – like Goldman Sachs, who sold its clients doomed derivatives even while betting against them – deliberately pushing us to our own excess and expecting to profiteer from our downfall?