Antibiotics ... Bueller?

They are no longer the "cure all" people think they were. Illustrated by this article.

By late March, Mr. Armbruster, then 78, was dead. After a series of postsurgical complications, the final blow was a bloodstream infection that sent him into shock and resisted treatment with antibiotics.

Not until the day Mr. Armbruster died did a laboratory culture identify the organism that had infected him: Acinetobacter baumannii.

The germ is one of a category of bacteria that by some estimates are already killing tens of thousands of hospital patients each year. While the organisms do not receive as much attention as the one known as MRSA -- for methicillin-resistant Staphylococcus aureus -- some infectious-disease specialists say they could emerge as a bigger threat.

Also ...

Meanwhile, New York City hospitals, perhaps because of the large numbers of patients they treat, have become the global breeding ground for another drug-resistant Gram-negative germ, Klebsiella pneumoniae.

For Gram-positives we need better drugs; for Gram-negatives we need any drugs. - Dr. Brad Spellberg, author of Rising Plague

No talking in class!

For all microbiologists not living in a cave, we all know that we're really losing the war against pathogenic bacteria, at least on the antibiotic front. Even the most potent antibiotics like vancomycin -- often considered the antibiotic of last resort -- have seen some organisms develop resistance to it. So, it's time for either new drugs, or a new approach. A New Scientist article discusses developing new antibiotics which target quorum sensing. The article is based on a communication in Chemical Communications, entitled: Towards quorum-quenching catalytic antibodies. The process of quorum sensing is described as following in the NS article:

Individual bacteria monitor the concentration of signalling molecules, and when it reaches a certain level, change their behaviour. That concentration provides a rough indication of when the number of cells in a particular population has reached a certain critical mass – known as a quorum.

So? This process, the authors hypothesize, can be targetted in what they call "antivirulence therapy".

Bacterial antivirulence therapies seek to avoid the development of treatment-induced resistance.

The NS article continues to explain:

But hacking the bacterial communication system could make it possible to prevent this transformation, and leave the cells waiting in a safe form for an attack signal that never comes. That would give the immune system extra time to naturally clear the bacteria from the body, says David Spring at the University of Cambridge, UK.

Of course, that does mean that the body needs to clear the infection on its own. In some circumstances, that may not be possible. But at any rate, how can they do it? They plan on designing antibodies to these quorum molecules. These antibodies will degrade the quorum molecules upon contact, or at least that is the hope/plan.

Reference
Prashant B. Kapadnis, Evan Hall, Madeleine Ramstedt, Warren R. J. D. Galloway, Martin Welch, David R. Spring (2009). Towards quorum-quenching catalytic antibodies Chemical Communications (5) DOI: 10.1039/b819819e