Certain types of life-threatening bacteria are no longer killed by current antibiotics, creating a need to develop new compounds to fight them. Scientists have been studying proteins produced by animals and humans, called cationic antimicrobial peptides (CAMPs), that the body uses to fight off infections. Recently, scientists developed a new method to identify CAMPs, and they hope the method can uncover CAMPs that are effective against dangerous bacteria.

An image of the bacterium Mycobacterium tuberculosis, which causes TB. Credit: NIAID.
CAMPs, like many antibiotics, act by targeting the protective “skin” of bacteria, called the membrane, which causes the bacteria to break open and die. However, each CAMP only works against certain types of bacteria, and CAMPs effective against the most dangerous bacteria, not killed by current antibiotics, are elusive. Identifying new CAMPs is difficult, but scientists in Virginia have come up with a new way to find CAMPs. Their technique involves taking samples of molecules from an animal, using a jello-like substance to capture CAMP look-a-like molecules, and then using a powerful technique that identifies all of those molecules. They expose different types of bacteria to the molecule; if the bacteria dies, the molecule is a CAMP for that particular type of bacteria. Unfortunately, the molecules they found in this study, from alligators, could only kill a few kinds of bacteria. However, this technique creates the opportunity to identify more molecules from other animals that might be useful to fight infectious bacteria.

Unfortunately, the promise of new CAMPs does not mean that we will have permanent weapons to fight against germs. Just as bacteria have built resistance to current antibiotics, changing their “skins” so that antibiotics can no longer break them open, bacteria can also develop ways to evade new CAMPs. Thoughtful and careful use of antibiotics and CAMPs will be important to prevent bacteria from building resistance faster than we can create new antibacterial compounds.

Managing Correspondent: Emily Low

Acknowledgments: Special thanks to Patricia Rohs, a graduate student in the Biological and Biomedical Sciences program at Harvard, for providing expert advice on the topic of antibiotics.

Original journal article: Bioprospecting the American Alligator (Alligator mississippiensis) Host Defense Peptidome

Other media coverage: NewScientist

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