http://community.victoriaadvocate.com/home/Blog/Crobar/5404 People often ask me for proof of evolution "in action" or "happening now".  After reading current stories in newspapers and online about the new deadly strain of anti-biotic resistant Staphylococcus aureus, it makes my job in those instances easier - just e-mail them the news stories. A new strain of resistant Staph has been noticed - a "superbug".  A superbug is a strain of bacteria or other microorganism (bacteria are often referred to as "bugs") that is extremely resistant to first line medications (such as antibiotics).  These can be common bacteria which are known for being easy to treat.  However, we see evolution through natural selection work and what happens?  Superbugs. This is shown through the numbers from a paper authored by Jaime Fergie and Kevin Purcell in the journal Pediatric Annals.  The strain is referred to as Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).  In the article, Fergie and Purcell state that: "Since the first case reports of methicillin-resistant S. aureus (MRSA) infections in the United States in 1968, MRSA has become an increasing problem, now accounting for 50% or more of the nosocomial S. aureus isolates nationwide." Source - Fergie, J. and Purcell, K. (2007). The Epidemic of Methicillin-Resistant Staphylococcus aureus Colonization and Infection in Children: Effects on the Community, Health Systems, and Physician Practices. Pediatric Annals, 36, 402-412. I'd say that constitutes a problem. So how does this happen?  Well folks, it's "evolution in action".  Let's take a single person who has a bacterial infection.  The person goes to their physician who prescribes an appropriate antibiotic.  The person is instructed to take all the antibiotics even if they feel better.  Let's say John Doe feels better after a couple of days and stops taking the meds.  Well, what John doesn't realize is that he's killed off the least resistant bacteria but they aren't all gone (and still enough to keep his immune system busy, busy, busy - which is why extra help is needed).  The bacteria who are more resistant to the antibiotics are the ones that are left and then they begin to reproduce.  John starts to feel sick again and even worse than before. With our societies use of anitbiotics we've saved untold millions of lives.  However, there's always those little bugs which are genetically configured with the ability to be unfazed by the medications.  These are the little bugs that reproduce and create their own little communities of drug resistance - superbugs.  Natural selection worked in this instance to select for organisms with heightened resistance to antibiotics and over time we get the prevalence of these superbugs rising - evolution in action. The strains of staph aren't the only ones and this isn't a recent thing.  The prevalence of such strains has been steadily rising over the past several decades.  So if there's someone who wants "proof" of "evolution in action" or evolution itself - there you have it, ripped from the headlines. People often ask me for proof of evolution "in action" or "happening now".  After reading current stories in newspapers and online about the new deadly strain of anti-biotic resistant Staphylococcus aureus, it makes my job in those instances easier - just e-mail them the news stories. A new strain of resistant Staph has been noticed - a "superbug".  A superbug is a strain of bacteria or other microorganism (bacteria are often referred to as "bugs") that is extremely resistant to first line medications (such as antibiotics).  These can be common bacteria which are known for being easy to treat.  However, we see evolution through natural selection work and what happens?  Superbugs. This is shown through the numbers from a paper authored by Jaime Fergie and Kevin Purcell in the journal Pediatric Annals.  The strain is referred to as Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).  In the article, Fergie and Purcell state that: "Since the first case reports of methicillin-resistant S. aureus (MRSA) infections in the United States in 1968, MRSA has become an increasing problem, now accounting for 50% or more of the nosocomial S. aureus isolates nationwide." Source - Fergie, J. and Purcell, K. (2007). The Epidemic of Methicillin-Resistant Staphylococcus aureus Colonization and Infection in Children: Effects on the Community, Health Systems, and Physician Practices. Pediatric Annals, 36, 402-412. I'd say that constitutes a problem. So how does this happen?  Well folks, it's "evolution in action".  Let's take a single person who has a bacterial infection.  The person goes to their physician who prescribes an appropriate antibiotic.  The person is instructed to take all the antibiotics even if they feel better.  Let's say John Doe feels better after a couple of days and stops taking the meds.  Well, what John doesn't realize is that he's killed off the least resistant bacteria but they aren't all gone (and still enough to keep his immune system busy, busy, busy - which is why extra help is needed).  The bacteria who are more resistant to the antibiotics are the ones that are left and then they begin to reproduce.  John starts to feel sick again and even worse than before. With our societies use of anitbiotics we've saved untold millions of lives.  However, there's always those little bugs which are genetically configured with the ability to be unfazed by the medications.  These are the little bugs that reproduce and create their own little communities of drug resistance - superbugs.  Natural selection worked in this instance to select for organisms with heightened resistance to antibiotics and over time we get the prevalence of these superbugs rising - evolution in action. The strains of staph aren't the only ones and this isn't a recent thing.  The prevalence of such strains has been steadily rising over the past several decades.  So if there's someone who wants "proof" of "evolution in action" or evolution itself - there you have it, ripped from the headlines. en-us Please give me a break.  This is no proof of evolution.  It's diversification.  As far as I know the bug is still a staph bug, just a meaner version. As far as I know, that is why evolution cannot be proven by anyone.  It is still a theory. http://community.victoriaadvocate.com/home/Blog/Crobar/5404/#c_20546 http://community.victoriaadvocate.com/home/Blog/Crobar/5404/#c_20546 Please give me a break.  This is no proof of evolution.  It's diversification.  As far as I know the bug is still a staph bug, just a meaner version. As far as I know, that is why evolution cannot be proven by anyone.  It is still a theory. I appreciate your input deyamorgan.  However, by definition, the example provided by antibiotic resistant strains of Staph is evolution.  Evolution is formally defined by Audesirk, Audesirk, and Byers (2002) as, "the descent of modern organisms with modification from preexisting life-forms; strictly speaking, any change in the proportions of different genotypes in a population from one generation to the next." (G-9). Such an example as this would fall into the change in proportions of genotype in subsequent generations.  The interaction with the environment is what produces the change.  Diversity if what we see as a product of natural selection working on populations of organisms.  Those bacteria which were more resistant to the antibiotics are the ones who persisted and were therefore able to reproduce.  Evolution is not bound to be only a speciation event which is what most people think of.  They are still classified taxonomically as Staph, yes, but evolution has still taken place.  It must also be understood that individual organisms do not evolve, populations do. As far as evidence is concerned, there is much support for descent with modification - one aspect which offers evidence of common ancestry is homology which I typed up a short blog on as well.  I think much confusion arises when one is not familiar with the concepts themselves and may have received distorted or incorrect information.  Evolutionary theory is a large and far-reaching theory yet one which has much empirical support from many disciplines in science besides basic biology such as geology, paleontology, anthropology, medicine, neuroscience, et al. I'd also like to address the term "theory".  The term, like many words in the English language has several definitions.  This can lead to an unintentional fallacy called equivocation.  Equivocation is defined as, "A term or expression is used ambiguously or equivocally in an argument when it is used in one sense in one place and in another sense in another.  When we fail to notice a shift in meaning of this kind and are led to accept a conclusion that we otherwise would have denied, then we are victims of the fallacy of equivocation (Kahane and Tidman, 1995, p. 311)". In this instance, as you pointed out in your comment, "theory" is taken to mean something that is equivalent to a "guess" or "conjecture".  This usage of the word is what is referred to as the colloquial or "everyday language" use of the term.  However, within a scientific context "theory" is utilized in another way.  When one refers to a "theory" in science the term takes on a different definition - "A set of statements or principles devised to explain a group of facts or phenomena, esp; one that has been repeatedly test or is widely accepted” (Pickett, 2001)".  To utilize the term "theory" as just a conjecture in describing Evolutionary theory is to necessitate application of the same usage to other scientific theories as well such as the theory of gravity, the germ theory of disease, cell theory and so forth.  Most would not argue that these theories are simply conjecture or just a guess. References (in order of appearence): Audesirk, T., Audesirk, G., & Byers, B. (2002). Biology: Life on earth. (6th ed.). Upper Saddle River: Prentice Hall. Kahane, H. and Tidman, P. (1995). Logic & Philosophy: A Modern Introduction. (7th ed.). Belmont: Wadsworth Publishing. Pickett, J. (Ed.) (2001). The American Heritage Dictionary.  New York: Dell Publishing. If you'd be interested in looking more into the topic, here are some recommendations for starting points: Many decent texts can be found online or at used book stores (hey, why full price when someone else already did?): Evolution by Mark Ridley Evolutionary Biology by Douglas J. Futuyma Some webpages with some good, solid information: Evolution 101 from the University of California-Berkeley Museum of Paleontology Talk.Origins - Introduction to Evolutionary Biology And if you would like to keep up with some of the latest research in the field (Both are open access, peer-review, scientific journals): BMC Evolutionary Biology PLoS Biology http://community.victoriaadvocate.com/home/Blog/Crobar/5404/#c_20556 http://community.victoriaadvocate.com/home/Blog/Crobar/5404/#c_20556 I appreciate your input deyamorgan.  However, by definition, the example provided by antibiotic resistant strains of Staph is evolution.  Evolution is formally defined by Audesirk, Audesirk, and Byers (2002) as, "the descent of modern organisms with modification from preexisting life-forms; strictly speaking, any change in the proportions of different genotypes in a population from one generation to the next." (G-9). Such an example as this would fall into the change in proportions of genotype in subsequent generations.  The interaction with the environment is what produces the change.  Diversity if what we see as a product of natural selection working on populations of organisms.  Those bacteria which were more resistant to the antibiotics are the ones who persisted and were therefore able to reproduce.  Evolution is not bound to be only a speciation event which is what most people think of.  They are still classified taxonomically as Staph, yes, but evolution has still taken place.  It must also be understood that individual organisms do not evolve, populations do. As far as evidence is concerned, there is much support for descent with modification - one aspect which offers evidence of common ancestry is homology which I typed up a short blog on as well.  I think much confusion arises when one is not familiar with the concepts themselves and may have received distorted or incorrect information.  Evolutionary theory is a large and far-reaching theory yet one which has much empirical support from many disciplines in science besides basic biology such as geology, paleontology, anthropology, medicine, neuroscience, et al. I'd also like to address the term "theory".  The term, like many words in the English language has several definitions.  This can lead to an unintentional fallacy called equivocation.  Equivocation is defined as, "A term or expression is used ambiguously or equivocally in an argument when it is used in one sense in one place and in another sense in another.  When we fail to notice a shift in meaning of this kind and are led to accept a conclusion that we otherwise would have denied, then we are victims of the fallacy of equivocation (Kahane and Tidman, 1995, p. 311)". In this instance, as you pointed out in your comment, "theory" is taken to mean something that is equivalent to a "guess" or "conjecture".  This usage of the word is what is referred to as the colloquial or "everyday language" use of the term.  However, within a scientific context "theory" is utilized in another way.  When one refers to a "theory" in science the term takes on a different definition - "A set of statements or principles devised to explain a group of facts or phenomena, esp; one that has been repeatedly test or is widely accepted” (Pickett, 2001)".  To utilize the term "theory" as just a conjecture in describing Evolutionary theory is to necessitate application of the same usage to other scientific theories as well such as the theory of gravity, the germ theory of disease, cell theory and so forth.  Most would not argue that these theories are simply conjecture or just a guess. References (in order of appearence): Audesirk, T., Audesirk, G., & Byers, B. (2002). Biology: Life on earth. (6th ed.). Upper Saddle River: Prentice Hall. Kahane, H. and Tidman, P. (1995). Logic & Philosophy: A Modern Introduction. (7th ed.). Belmont: Wadsworth Publishing. Pickett, J. (Ed.) (2001). The American Heritage Dictionary.  New York: Dell Publishing. If you'd be interested in looking more into the topic, here are some recommendations for starting points: Many decent texts can be found online or at used book stores (hey, why full price when someone else already did?): Evolution by Mark Ridley Evolutionary Biology by Douglas J. Futuyma Some webpages with some good, solid information: Evolution 101 from the University of California-Berkeley Museum of Paleontology Talk.Origins - Introduction to Evolutionary Biology And if you would like to keep up with some of the latest research in the field (Both are open access, peer-review, scientific journals): BMC Evolutionary Biology PLoS Biology Thank you Cory for this timely report on MRSA, and also for recognizing that it is not a recent development, although now that the media is blowing the subject all out of proportion, there may be a danger of it becoming the "bug du jour". I can tell you from personal experience that beta-lactamase positive strains of Staph aureus (penicillin and ampicillin resistant) were not altogether common even 20 years ago. Jump to present-day: I have not seen a strain of S. aureus that is NOT beta-lactamase positive in some time. As for MRSA, when we would recover those in the lab, say, 5 to 10 years ago, it was not a common occurrence, and a rather big deal, especially for infection control. Now, I would say roughly 70% of the S. aureus strains we recover from the lab are MRSA. I have seen the bacteria recovered from boils, wounds, sputum, stool, blood, you name it. A big problem for the past 10 years has been that the doctors have been on the offensive rather that the defensive when it comes to antibiotics. While at first glance, this may appear to be proactive medicine at its best, it is not. It is like trying to shoot a bumblebee with a bazooka. OVERKILL. Many patients are placed in isolation and started on vancomycin, gentamycin, tobramycin (three HEAVY DUTY antibiotics that can compromise renal function if not used prudently) before we have even identified a causative bug and performed sensitivities. Sometimes we just recover a non-MRSA staph, or a garden variety E. coli, which is best treated with routine antibiotics. And with all due respect to deyamorgan, I prefer not to get into a heated discussion on evolution, but will tell you that these bacteria become resistant just as Cory says, by changing their actual genome to get around these first-line antibiotics. The beta-lactamase enzyme produced by many bugs these days actually cleaves the beta-lactam ring of penicillin drugs, rendering them ineffective. This is adaptation at its finest. Many gram negative organisms we recover now (such as certain strains of E. coli, Klebsiella sp., etc.) have become fluorquinolone resistant, are now exhibiting extended-spectrum beta-lactamase production, and a select few have become AMP-C positive, a novel new way of cleaving and therefore rendering ineffective even newer antibiotics. These bacteria are indeed adapting and surviving, perhaps even thriving. http://community.victoriaadvocate.com/home/Blog/Crobar/5404/#c_20703 http://community.victoriaadvocate.com/home/Blog/Crobar/5404/#c_20703 Thank you Cory for this timely report on MRSA, and also for recognizing that it is not a recent development, although now that the media is blowing the subject all out of proportion, there may be a danger of it becoming the "bug du jour". I can tell you from personal experience that beta-lactamase positive strains of Staph aureus (penicillin and ampicillin resistant) were not altogether common even 20 years ago. Jump to present-day: I have not seen a strain of S. aureus that is NOT beta-lactamase positive in some time. As for MRSA, when we would recover those in the lab, say, 5 to 10 years ago, it was not a common occurrence, and a rather big deal, especially for infection control. Now, I would say roughly 70% of the S. aureus strains we recover from the lab are MRSA. I have seen the bacteria recovered from boils, wounds, sputum, stool, blood, you name it. A big problem for the past 10 years has been that the doctors have been on the offensive rather that the defensive when it comes to antibiotics. While at first glance, this may appear to be proactive medicine at its best, it is not. It is like trying to shoot a bumblebee with a bazooka. OVERKILL. Many patients are placed in isolation and started on vancomycin, gentamycin, tobramycin (three HEAVY DUTY antibiotics that can compromise renal function if not used prudently) before we have even identified a causative bug and performed sensitivities. Sometimes we just recover a non-MRSA staph, or a garden variety E. coli, which is best treated with routine antibiotics. And with all due respect to deyamorgan, I prefer not to get into a heated discussion on evolution, but will tell you that these bacteria become resistant just as Cory says, by changing their actual genome to get around these first-line antibiotics. The beta-lactamase enzyme produced by many bugs these days actually cleaves the beta-lactam ring of penicillin drugs, rendering them ineffective. This is adaptation at its finest. Many gram negative organisms we recover now (such as certain strains of E. coli, Klebsiella sp., etc.) have become fluorquinolone resistant, are now exhibiting extended-spectrum beta-lactamase production, and a select few have become AMP-C positive, a novel new way of cleaving and therefore rendering ineffective even newer antibiotics. These bacteria are indeed adapting and surviving, perhaps even thriving.