Superbugs and their evolution

[Bio-Hazard]

Why do antibiotic super bugs keep evolving more and more so they are resistant to antibiotics?

 

Wouldn't this evolution be considered on a macroscale or would you say microscale seeing as how they are becoming stronger and stronger?

 

It's interesting to learn that these things are becoming more and more powerful through last century and this century. Why do these things evolve so quickly and yet we as humans don't really have a greatly evolving immune system?

[Skye]

Why do antibiotic super bugs keep evolving more and more so they are resistant to antibiotics?

Natural selection, the ones without resistance die.

Why do these things evolve so quickly and yet we as humans don't really have a greatly evolving immune system?

They have shorter generation times, higher mutation rates and plasmids that can be spread between cells.

[Bio-Hazard]

Would you consider it macro?

[Yggdrasil]

Why do antibiotic super bugs keep evolving more and more so they are resistant to antibiotics?

 

The problem can be attributed to both patients and doctors. Patients will often quit taking antibiotics after the symptoms of their infection have gone away. While this will still allow them to recover alright, it leaves a small population of bacteria which are more resistant to the antibiotic. Had the patient taken the full course of antibiotics, the entire population of bacteria would have likely been eliminated, preventing the more resistant bacteria from propagating their resistance genes.

 

Doctors make the problem worse because they often prescribe antibiotics when they're not needed. Hospitals teach doctors to prescribe antibiotics even for viral infections just so that the patient thinks the doctor did something to help him/her and they don't walk away empty-handed. Worse, some patients will demand antibiotics as a treatment for their cold and the doctor will prescribe them so that their patient doesn't go elsewhere.

 

Why do these things evolve so quickly and yet we as humans don't really have a greatly evolving immune system?

 

Generation times. Some bacteria reproduce every 20 minutes. Most humans wait until they are around 20-30 years old before they begin to reproduce. By the time one human generation passes, a huge number of generations of bacteria will have passed. More generations amounts to a greater chance that a random mutation will benefit the organism and it also gives the gene time to propagate throughout the population.

[Skye]

What exactly do you mean by macro?

[ecoli]

macroevolution http://www.google.com/search?q=define%3A+macroevolution&sourceid=mozilla-search&start=0&start=0&ie=utf-8&oe=utf-8&client=firefox-a&rls=org.mozilla:en-US:official

 

microevolution

http://www.google.com/search?hs=Nzo&hl=en&lr=&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=define%3A+microevolution&btnG=Search

 

I would consider this micro, at least when dealing with individual species. If other organisms can evolve to accommodate these changes, resulting in cross species evolution, perhaps on a global scale, then this would be macroevolution.

[Bio-Hazard]

I like to think of it in terms of how much of an evolution it is.

 

I consider polydactyl cats with mitten paws to have microevolved. ==

They got more fingers than the average cat!

 

However, being that bacteria are super super tiny, I would think they evolved greatly since having a greater resistance to the world around them has evolved.

 

I mean, if our human immune system evolved on such a great level that it could aid in our survival in even more hazardous environments, I would consider that a macro-level evolution.

[Mokele]

Well, micro and macro evolution have little do do with the scale of changes and more with the state of the population. Microevolution is changes within a population, like bacterial resistance to antibiotics. Now, if we have two populations of bacteria, and one evolves a cell wall that cannot be penetrated by a particular antibiotic, but which also makes it unable to conjoin (exchange genetic information) with bacteria who lack the modified cell wall, it would be macroevolution, as the two populations have become genticly isolated.

 

In general, microevolution means below species level, and macroevolution means speciation, and evolutionary processes at higher taxonomic levels. However, it should be noted that they are two sides of the same coin; microevolution inevitably leads to macroevolution. The distinction is more an artifical categorization that we impose to make it easier to talk about than any real divide.

 

Mokele