darwinian medicine

Scott A Hoffman schoffma at badlands.NoDak.edu
Wed Oct 4 19:44:03 EST 1995

	Hello, my name is Scott and I am a graduate student at the 
University of North Dakota.  Our current seminar topic of the semester is 
emerging infectious diseases, and a few things have caught my attention.  
The topics chosen have been on (and will in some way deal with) 
treatment, specifically chemotheraputic control (e.g., antibiotics, 
metabolic structural analogues, etc.).  I am hoping that those reading 
this post can give me some information or point me in the right 
	In a nutshell I'm am interested in the incorporation of 
Darwinian ideals into current medical thinking (an idea presented in the 
Quaterly Review of Biology, vol 66 no.1 by Williams and Nesse).  So far 
two of the presentaions have dealt with antibiotic resistance. For example, 
is showing widespread resistance to vanomycin.  One of my questions is 
this:  If a population of vancomycin resistant cells were selected for by 
vancomycin treatment, and then the selective pressure of vancomycin was 
removed, would it be resonable to believe that a population of vancomycin 
sensitive cells would eventually outcompete and re-establish itself?  As 
I understand vancomycin resistance is encoded by about 6 genes.  There 
must be an energy cost in maintaining these genes (paid for in ATP, 
etc.).  A cost that sensitive cells do not have to pay.  This may be a 
bad example since (if I understood the presenter correctly) vancomycin 
can be inserted stably onto the chromosome through transposition, and  
more importantly that this set of genes is inducible (less energy 
maintainence).  But there are other antibiotic resistance examples that 
are not so dramatic.  Do these type of reversions usually occur?  If the 
medical community were to completely "black out" the use of certain 
antibiotics in predetermined areas for a period of time could it be 
possible to re-establish non-resistant strains?  I know that this is a 
bit simplistic, and there are probably a million inherent problems.  
World travel doesn't lend itself well either, the spread of disease and 
antibiotic resistance is a factor.  But I could see the possible benefits 
to nocosomial infections.
	Are there other ways to incorporate evolutionary thought into 
medical microbiology?  If anyone could please send me your thoughts but 
more importantly the names and locations of articles with experiments and 
data that might be helpful from the evolutionary standpoint.  My 
presentaion will be on a virus (a big leap from bacteria I know) 
and any information there would be appreciated.  Please e-mail me  at 
schoffma at badlands.nodak.edu or feel free to post answers at this site.  
Thanks in advance.   

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