# Neosporin's been around forever. Are all of the bugs immune to it by now? **URL:** \ **Category:** Factual Questions\ **Created:** [May 25, 2006, 2:43am UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125 "2006-05-25T02:43:00Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Ringo](https://avatars.discourse-cdn.com/v4/letter/r/779978/32.png) [@Ringo](https://boards.straightdope.com/u/Ringo)\ **Post date:** [May 25, 2006, 2:43am UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/1 "2006-05-25T02:43:00Z")
I think that’s got it all in the title. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [May 25, 2006, 3:05am UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/2 "2006-05-25T03:05:00Z")
Evolution on a grand scale simply does not work that fast and it would be scary if it did. Hundreds of thousands of years is considered fast and changes below that are considered lightening speed. Humans are good at inventing stuff but we aren’t that good at making the entire microbial world adapt its DNA structure around a topical cream that has been around for a few decades. Of course there are some strains that have become resistant. The vast majority have nave not and that is why it remains useful for most purposes. We are but a small part of the world regardless of what we may feel and creams tend not to alter whole worlds that have been and will be long after we are all gone. ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [May 25, 2006, 7:36am UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/3 "2006-05-25T07:36:02Z")
No. Mainly because it’s not to the bug’s advantage to keep producing the counter to each antibiotic in Neosporin (I think it’s Bacitracin and Polymyxin B and Neomycin maybe). While strict human pathogens probably want to keep those genes around and expressing for continual infection, bacteria that is surviving out in the environment that doesn’t have to commit extra energy to anti-antibiotics will fare better (divide faster, save energy) than those bacteria that keep the genes around. I use Neosporin but I’m not sure why really, my immune system likely kills all of that stuff anyhow. I guess better safe than sorry. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [May 25, 2006, 11:33am UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/4 "2006-05-25T11:33:50Z")
Unless someone is running around rubbing Neosporin on bugs, how would bugs become immune to it? I would think that a human that uses it on an almost daily basis could develop some immunity and it could become less effective when used to treat bug bites and stings. ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [May 25, 2006, 1:20pm UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/5 "2006-05-25T13:20:43Z")
> [@racer72](#): > > Unless someone is running around rubbing Neosporin on bugs, how would bugs become immune to it? I would think that a human that uses it on an almost daily basis could develop some immunity and it could become less effective when used to treat bug bites and stings. **Humans** don’t develop immunity to antibiotics (or, more accurately, they normally already are immune in the sense that the antibiotics don’t cause them problems); micro-organisms develop immunity to antibiotics. ---
**Author:** ![Doctor\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doctor_jackson/32/32_2.png) [@Doctor\_Jackson](https://boards.straightdope.com/u/Doctor_Jackson)\ **Post date:** [May 25, 2006, 1:51pm UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/6 "2006-05-25T13:51:47Z")
> [@racer72](#): > > Unless someone is running around rubbing Neosporin on bugs, how would bugs become immune to it? I would think that a human that uses it on an almost daily basis could develop some immunity and it could become less effective when used to treat bug bites and stings. Do what? People do not become immune to antibiotics, it is bacteria that become resistant([cite](http://www.sciam.com/askexpert_question.cfm?articleID=00081E33-3CD5-1063-BCD583414B7F0000)). From that page: > [@](#): > > The concept of antibiotic immunity is a misnomer that can lead people to believe that they may become “immune” or “resistant” to an antibiotic if they take it too frequently or inappropriately. This notion stems from a misunderstanding in the general public of the concept of antibiotic resistance. It is not people who become immune or resistant to an antibiotic. Rather it is the bacteria responsible for infections that become resistant. > [@Shagnasty](#): > > Evolution on a grand scale simply does not work that fast and it would be scary if it did. Hundreds of thousands of years is considered fast and changes below that are considered lightening speed. This is not evolution in action, it’s adaptation and it can take place very quickly. Again, from the above cite: > [@](#): > > Misuse or overuse of antibiotics selects for resistant bacteria. In a bacterial infection, billions of bacteria are present. Taking an antibiotic will kill or inhibit those bacteria that are susceptible to its effects and leave behind a subpopulation of bacteria that are resistant to the antibiotic. These remaining bacteria can survive and continue to grow. If they then spread from person to person, they may become the norm, and all future infections caused by these resistant bacteria will withstand the original antibiotic, rendering it useless for treatment. “Decades” would be plenty of time for a particular strain of bacteria to become resistant. As a matter of fact, it’s a big worry in the medical field. See this WebMD article for example: [Super Bugs Pose Bigger Threat than SARS](http://www.webmd.com/content/article/64/72307.htm) > [@](#): > > “We’re even running out of drugs to treat our most common infections. Not just less common hospital-based infections,” says Neil Fishman, MD, director of the department of healthcare epidemiology and infection control at the University of Pennsylvania Medical Center…Although antibiotic resistance has been around since the discovery of antibiotics more than 60 years ago, the problem has grown exponentially in recent years due to a combination of factors that Fishman calls a “perfect storm.” **Ringo** , the links above are very good articles on antibiotic immunity, though they don’t answer the Neosporin question specifically. My WAG would be that, since Neosporin is a “cocktail” of antibiotics, it defeats multiple resistance mechanisims commonly present in bacteria. Beond that, I got nothin’. ---
**Author:** ![saoirse](https://avatars.discourse-cdn.com/v4/letter/s/5daacb/32.png) [@saoirse](https://boards.straightdope.com/u/saoirse)\ **Post date:** [May 25, 2006, 1:57pm UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/7 "2006-05-25T13:57:39Z")
It’s when they develop a resistance to isopropyl that I’ll start worrying. ---
**Author:** ![KP](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KP](https://boards.straightdope.com/u/KP)\ **Post date:** [May 25, 2006, 2:47pm UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/8 "2006-05-25T14:47:51Z")
Developing antibiotic resistance in bacteria in vivo (vs. in a test tube) is much more complicated than it seems. Quite often, it’s really a combination of _selection_ of already resistant strains/species through preferential growth, and transduction of genetic material between strains and _very_ different species (it’d be like us absorbing lobster genes) Even disrgarding the details of exposure frequency/duration, mechanisms of action, etc., it’s useful to remember that the concentration of antibiotics in a topical ointment can safely be MUCH higher than the serum/tissue concentrations of antibiotics taken internally. Resistance is rarely absolute. It can be overcome if the concentration is high enough ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [May 25, 2006, 6:28pm UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/9 "2006-05-25T18:28:13Z")
> [@Ringo](#): > > I think that’s got it all in the title. Neosporin and similar topical anti-biotics kill the bacteria at the site of a wound to prevent/miniize risk of infection. No bacteria should survie to procreate offspring with increased resistance. It is when patients refuse to finish a course of Rx medication that bugs go on the loose to infect others and procreate more reisistant offspring. ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [May 25, 2006, 9:25pm UTC](https://boards.straightdope.com/t/neosporins-been-around-forever-are-all-of-the-bugs-immune-to-it-by-now/358125/10 "2006-05-25T21:25:00Z")
> [@saoirse](#): > > It’s when they develop a resistance to isopropyl that I’ll start worrying. And bleach. Fortunately 70% ethanol pretty much unfolds every protein, and I don’t see how anything could counter bleach chemical modification, it’s so reactive. Of course the mold growing in my shower seems to survive it just fine ☹