Want to kill Staph? Turn on the lights

So here’s something new: as summarized in this Science Daily article, scientists at the University of New Mexico are looking at a novel strategy for the elimination of bacteria from surfaces. The need is great for us in the United States. As noted by Science Daily:

… increased infection and resistance rate has not been met with a simultaneous development of novel antimicrobial and antibiotic agents; in fact, only three classes of antibiotics have been developed since the 1950s…

The researchers at UNM are utilizing a novel set of compounds (“conjugated polyelectrolytes” or CPEs) that have marked bacteriocidal activity towards Gram negative bacteria. Newly developed light-activated CPEs are essentially inert to living cells when they are in the dark, but are bacteriocidal when exposed to light. There are many potential applications from this technology, one of which as discussed by the editor of Science Daily could be to ultimately incorporate these materials into a new type of antibacterial countertop that can be sterilized by turning on the lights.  One issue that must be resolved before such applications can be pursued is to assess the toxic effects on mammalian cells. It wouldn’t be a very effective approach for giving you a clean surface if it is just as toxic to you, now would it? But if it proves to be a safe compound (to us) for making a countertop or cutting board from, I do foresee that this approach would have a significant benefit for avoiding the issue raised in the Science Daily blockquote at the top (“increased infection and resistance rate“) that we are observing by the use of antimicrobial compounds in everyday use.  Consider the mechanisms we discussed in Chapters 9 and 10 for antimicrobial resistance, and suggest something in the comments that this approach might circumvent to a degree!


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on November 3, 2010, in Bonus!, Microbes in the News, Strange but True. Bookmark the permalink. 5 Comments.

  1. Bauman states that “Ideally, agents used for the control of microbes should be inexpensive, fast-acting, and stable during storage. Further, a perfect agent would control the growth and reproduction of every type of microbe while being harmless to humans, animals, and objects.” With this said, the countertops do not meet all of these qualifications. First, countertops are already expensive and adding antimicrobial technology would definitely raise the cost. Additionally, more tests should be done to make sure that they are stable during storage. The article states that they are non reactive without light but, how does it favor in terms of temperature? Also, the CPE compounds are mainly cidal for Gram-negative bacteria but, what about Gram-positive bacteria or Mycobacteria?

    • I’m suggesting that the interest in the technology is not the apparent specificity for Gr neg bacteria (although, as we’ll see next week, the Gr neg bugs are the most significant food-associated pathogens), but more to the on-off mechanism of delivery that the scientists describe.

  2. Kristen Trevino

    This approach would get around the problem of off-label usage of antibiotics. Since the light would be used to kill the bacteria in conjuction with the CPEs, this would be the only use for this system; also, the compounds are novel and the bacteria would be killed using these compounds and the light since they have never come into contact with this system.

  3. This approach may be beneficial in the future, but significant research must first be done. It is essential to know what the CPE’s are killing in the Gram negative bacteria. By understanding this information, we would be aware of whether or not it is selectively toxic. As stated earlier, it is also important to prove that this method would not harm humans. It would be an expensive procedure that would limit the users, but it is an effective easy method for killing Gram negative bacteria. I foresee CPEs being a beneficial antibacterial agent in the future, after further research has been done.

  4. I agree with the concerns about toxicity raised above, however the digest of the article did indicate that the researchers at UNM were actively working on making those determinations. Let’s assume that in the end that there will be no safety concerns for light activated CPEs, and go from there. Here’s what I was thinking about: recall from the end of the chapters on the development of resistance to antimicrobial control agents, and how one reason was the constant, low level selective pressure that these agents put on microorganisms. Now we have a method for turning killing on and off with the flick of a switch, which means that microorganisms will not be constantly exposed to the selective pressure to develop resistance. That means the method will work longer.

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