Gaining Ground Against Germs
Antibiotic resistance may well be the greatest human crisis we face this century. After 70 years, we take the magic of antibiotics for granted. But consider this partial list of things that would be insanely risky, or perhaps impossible, without antibiotics to aid them:
- Organ transplants. The secret to organ transplantation is suppressing your immune system so that it won't attack the new, foreign organ. Without antibiotics, this would be insanely dangerous and have a very high rate of failure.
- Elective surgery. Every time you open a hole in someone's body, you're opening up a highway for foreign bacteria to colonize the virgin territory of your flesh. That's not such a big deal these days, because we have antibiotics to control any resulting infections. Without them, however, elective surgery -- everything from cosmetic surgery to knee replacements -- would become much more risky. That includes abortions; the grisly statistics you hear about the death toll from back-alley abortions date from the pre-antibiotic era. Even before abortion was legalized, the number of annual deaths had plunged to less than 40, because antibiotics cleaned up any resulting infections. If antibiotic resistance becomes widespread, the annual death toll from abortion might well be higher than it was in 1970.
- Chemotherapy for cancer. Chemotherapy is extremely hard on the immune system, and as with organ transplants, we mitigate the resulting problems with antibiotic therapy. We might well still perform the chemotherapy, but we'd lose more patients from opportunistic infections.
- The sexual revolution. The radical mid-century change in sexual mores is usually dated to the invention of the pill -- but that's because the pill came second. Try to imagine today's campus sexual culture in a world where gonorrhea and other sexually transmitted diseases are untreatable. To be sure, that campus sexual culture survived AIDS. But as STDs go, AIDS is actually pretty hard to catch, especially from vaginal or oral sex. A culture where lots of people have sex with strangers, without antibiotics to cure any resulting infections, would be a culture where STDs spread like wildfire. And untreated, those STDs eventually cause things like sterility, collapsing noses and madness. And maybe we should bid a fond farewell to free love.
Gonorrhea, by the way, which is extremely contagious and causes pelvic inflammatory disease, is already showing up with resistance to all known antibiotics. So is tuberculosis. That's pretty scary stuff. So it's not surprising that this was headline news this morning: Scientists think they've found a new antibiotic that's harder for bacteria to develop defenses against.
Now, the headlines were a bit overblown. This is a substance they've developed by culturing a previously unknown bacteria, and so far, it looks promising: It's already been dosed in mice, and it looks good. However, there is many a slip between the cup and the lip, and we don't have a new antibiotic pill yet; we just have a new antibiotic candidate.
It's actually not all that hard to kill bacteria -- bleach, for example, does a very good job. What's hard to do is find a substance that will kill bacteria without also killing you . . . or get chewed up by your liver into harmless but useless compounds that don't much affect you or the germs. We won't know if we have found such a substance until we put the stuff into humans and see how they react. Nor is this some sort of silver bullet for the problem of antibiotic resistance. It's a new antibiotic, but it won't by itself replace all the old ones that are getting less effective.
That said, this is still huge news -- first because we do have a new and exciting compound, and second because of the way they discovered it:
And the platform used to find it is worth keeping an eye on.
A lot of people have had similar ideas to this one, based on the fact that the overwhelming majority of bacteria in any given environmental sample can't be readily cultured. These organisms may well be able to produce useful antibiotics and other natural products, but how will you ever be able to tell if you can't fish any of them out? In this work, Kim Lewis and Slava Epstein at Northeastern came up with a gizmo (the "iChip", a name that you'd think would have been taken several times by now), that tries to get around this problem. After taking a soil sample and diluting it into media, you dispense aliquots into the wells of this chip. Then the chip is placed back into the soil, in the same place the sample was taken from, where semipermeable membranes allow environmental factors (whatever they may be) to diffuse across. This gives, apparently, a much higher culture success rate.
New bacteria are great places for us to look for novel antibiotics, because those bacteria have been devoting themselves to the problem of killing their neighbors for millions of years. They've already done the tough work of plucking compounds that actually work out of the boundless ocean of compounds that might. Unfortunately, as Derek Lowe notes, it's often hard to culture those bacteria. This method promises a higher yield rate for these sorts of searches. Its not a silver bullet -- but it does give us more ammunition for our long twilight struggle against germs.
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