Now We Know Some Creepy Things About How Penicillin Destroys Bacteria

Illustration for article titled Now We Know Some Creepy Things About How Penicillin Destroys Bacteria

We know how penicillin works. It kills bacteria. But a new study shows that it's not nearly that simple.


Even when it can't kill a bacterium, penicillin forces the cell to kill itself.

Here's how penicillin is supposed to work. It invades a cell, usually a bacterial cell. A cell is constantly engaged in maintaining itself. Its most important defense is its cell wall. To keep the wall strong, it builds long strands of sugar, and links them together to form a barrier. The penicillin takes out an enzyme that helps build the links between the strands of sugar. The cell wall becomes shredded, the cell bursts, and the bacteria dies.


This is why an experiment involving specially engineered E. coli and specially designed penicillin was so odd. The bacteria was engineered so it had that enzyme, but didn't need it to build a good wall. The penicillin was designed only to take out the now-useless enzyme. The study was meant to see what happened in a cell when penicillin couldn't kill it. The bacteria still died. Why?

The study discovered that penicillin and drugs like it work not just because of what they do but because of what they don't do. Penicillin might take out an enzyme that weaves sugar strands into a wall, but it doesn't even remotely stop those strands from being made in the first place. In fact, it might cause the cell to pick up the pace when it comes to making those strands. The strands get made. They're useless. They immediately get broken down again. Then they get made again. The cell throws more and more of its energy into this futile task, until it drains its own resources and dies.

This might open up a new way to combat infections as antibiotics lose their effectiveness. If we can't make drugs to kill cells outright, perhaps we can find other cell mechanisms to exploit.

Top Image: Wellcome Trust

[Via Cell.]


Share This Story

Get our newsletter



Arrgh, I'm clearly missing something essential to this story. Explaining it to myself like I was a very obtuse 5 year-old:

Bacteria Bob builds sugar strands, then uses Enzymoglop (Bob has a robust Enzymoglop manufacturing industry) to glue those strands into a protective wall. Can't make walls out of sugar strands w/o Enzymoglop!

Penny Cillin targets Bob. Her style of kung-fu enables her to rip Enzymoglop right out of Bob's walls, turning his bulwark into collapsing piles of jagged sweetness. Penny easily Mola-Rams the Enzymoglop faster than Bob can create or apply it, and Bob dies.

Bacteria Bors, Bob's Swedish cousin, also builds sugar strands, and also produces an impressive amount of Enzymoglop. What's different is that Enzymoglop doesn't figure into Bors' national defense whatsoever— as a Swede, Bors prefers to snap his sugar strands together in Lego fashion and build his walls that way. Bors uses Enzymoglop primarily as a flavoring agent in his craft beer hobby, and occasionally makes candy fish out of it.

Penny now targets Bors. Her kung fu technique rips the Enzymoglop out of all of Bors' breweries and candy factories. Bors is sober and confection-deprived, but his Lego walls can't be gutted and shredded by Penny, the way Bob's were. Still, Bors remains on high alert, what with Bob's murderess terrorizing the area and all. So Bors applies the undesired productivity that comes with No More Beer to snapping together more walls, walls that Penny can't affect at all.

Then, Bors...dies from overwork? Somehow? He wasn't working himself to death the way Bob did, frantically investing in strands that were doomed to crumble the moment they got used in a wall. And Bors' strands and walls aren't useless against Penny, whose effectiveness is nil vs anything non-Enzymoglop reliant.

What am I missing?

tl;dr: If penicillin's ability to "take out" the mortar enzyme triggers the engineered E. coli's panic response and sends it into the same wall-building frenzy that kills standard bacteria through overwork, what kills the panicking, but structurally uncompromised strain? Crowding itself to death with surplus, penicillin-proof walls?