20 October 2006

Antibiotic Resistance iff Evolution

It's in print now, and as my friend who works at a dictionary company tells me, having something acknowledged in print is what it takes.

Bacteria have been steadily evolving to evade the action of antibiotics and infections are becoming more difficult to fight.

For instance, the CDC said, in 1972, only 2 percent of Staphylococcus aureus bacteria infections were drug-resistant but in 2004, 63 percent were.

In a few cases, no available antibiotics can cure an infection, and many more resist methicillin, a later-generation type of antibiotic. [ref]


This is not just a science issue for me, this one is PERSONAL. And I'm sure I'm repeating myself now, so feel free to skip. I've got a (non-contagious) skin condition called hidradenitis suppurativa (HS). Part of this involves bacterial infections in my apocrine sweat glands, primarily caused by staphylococcus aureus (staph). Staph is actually very common, something like 80% of the population have it sitting passively on our skin, and it doesn't do anything bad to them, but in me it gets inside my sweat pores and my body overreacts. So killing the staph should help treat my HS.

Keflex (cefalexin) is in the class of antibiotics called cephalosporins, which are part of the larger group called β-lactams. All β-lactams act by messing with bacterias' cell walls. I think I was prescribed Keflex when in my teens and college a few times, but it hasn't worked for ages. Amoxicillin is another type of β-lactam, and it used to work on me when I was in college and grad school, but sometime around 2004 we realized that it wasn't really doing anything anymore.

In case you're curious (or even if you're not), the term "penicillin" actually refers to a category of antibiotics including the originally discovered penicillin, and various derivatives of it including amoxicillin and methicillin. The penicillins and the cephalosporins are related in that they're both β-lactams and both act by breaking bacterial cell walls. Methicillin isn't actually used today, though it has lent its name to methicillin resistant staphylococcus aureus (MRSA, resistant staph). MRSA is actually any staph that's resistant to the penicillins.

Waitasec, amoxicillin is a penicillin. Amoxicillin doesn't work on me. I have staph. Holy smokes, I have MRSA! But wait, amoxicillin used to work... *thinks* *lightbulb!* Holy darwinism, Batman, I've evolved MRSA under my skin! ...ick... Yeah. And to make matters worse, having that MR stand for "multiple resistant" might be a more accurate description, b/c you may recall (or skim upwards) Keflex isn't a penicillin, it's a cephalosporin. And that too used to work but now doesn't, so my pretty pretty staph evolved that during my lifetime too.

THIS is one of the top reasons why I get really REALLY pissed when people deny evolution.

What I use these days is Levaquin (levofloxacin), part of the category of fluroquinolones, which is part of the quinalones. Unlike β-lactams, quinalones act by messing with the DNA and DNA transcription of bacteria. Interestingly, the use of Levaquin reveals another interesting feature of my MRSA: the FDA does not recommend Leva for MRSA, but only for the methicillin suscpetible strains. There is widespread incidence of quinalone resistant staph, possibly by overusage in European livestock. And yet, the MRSA that are in me are not resistant to quinalones despite being resistant to multiple forms of β-lactams. I see this as more evidence that my MRSA have evolved within me, though I haven't confirmed this with my dermatologist.

*sigh* That's enough ranting for me. Maybe I should take some microbiology courses. ;)


Candace said...

Sneaky little bacteria!
It's getting scary, isn't it? You could go to the hospital for some routine procedure and end up with a life-threatening infection.
I wonder how holistic medicine would approach this. I mean, you'd have to give yourself minute amounts of your own, personal strain of bacteria, which would only work for you, since it evolved inside you!

Candace said...

Crap. Not "holistic medicine." I meant homeopathy.

zandperl said...

Correct me if I'm wrong but...

As I understand it, holistic medicine (which you did not mean to refer to but I will reply to anyway) is more of a philosophy than a scientific medical practice. Sadly, there isn't scientific evidence that a patient having a good outlook on life will actually make their health better (I think I posted on the lack of correlation between holidays and terminally ill patents' deaths but I can't find it now), but it's still a nice way of doing things.

Homeopathy however, I feel has no merit whatsoever. There is no conclusive evidence that it works, its main principle (dilutions are stronger) is in direct contradiction to the principles of chemistry and physics, and there is no scientific reason why that principle should be valid. The only scientific thing that homeopathy bears resemblance to is vaccination, and medicine has a well researched understanding of how that works, and the actual process by which vaccinations are given (prior to exposure to the infectious agent) is NOT the same as how homeopathy is applied (during symptoms of the disease).

Man, I could write a whole post on this. It's on my to-do list now. If you're interested in it, if I don't post it in a month, remind me.

Allison said...

Homeopathy is utter quackery whose practitioners should be charged with fraud. It is impossible for it to work, given well-established laws of chemistry and physics. Homeopathy is no more effective than casting spells or praying to get better. It's that simple.

As for your MRSA... perhaps you should be praying for that to get better. This so-called "evolution" in your skin is really God changing the bacteria to punish you for your heathen blogging.

zandperl said...


Hah! Aweome! I can say in all honesty that's the best comment I've ever gotten. *grin*

Matt said...

I love that you used "iff". I loved using it but haven't seen it since college! I miss it!

Candace said...

I'm glad I came over to your blog today; I had actually forgotten to check for replies to this post.

Obvy, I know next to nothing about homeopathy. It was just the first thing I thought about when I read your post.

I look forward to your future post about it!