Evolution of Virulence: Lipopolysaccharide and Gram-negative organisms and DHEA and Antibiotic Resistance

Copyright 2005; James Michael Howard, Fayetteville, Arkansas, U.S.A.


I happened onto this topic while researching another area.  I am not a microbiologist.  I discovered that lipopolysaccharide causes a number of pathological effects, everyone of which, I would have attributed to low DHEA.  (I am of the opinion that all tissues depend upon DHEA for optimal function and think that mammals evolved as a result of selection for DHEA: “Hormones in Mammalian Evolution,” Rivista di Biologia / Biology Forum 2001; 94: 177-184).  Eventually, I found the following which explains why the effects of lipopolysaccharide may, indeed, cause the effects of low DHEA.  Lipopolysaccharide "markedly" depresses DHEAS sulfatase activity in another study, therefore, blocking conversion to DHEA (Endocrinology. 1994 Jul;135(1):67-75).


I suggest that lipopolysaccharide was selected by evolution because it reduces levels of DHEA and allows gram-negative organisms to avoid the immune response of an organism with ample amounts of DHEA.  DHEA improves the immune response.


Testosterone reduces immune response.  I suggest this is due to reduced availability of DHEA.  It is my hypothesis that the “secular trend” is caused by an increase in percentage of individuals of higher testosterone within populations with time.  Therefore, immune response declines.  This trend should produce demonstrable increases in infection rates, perhaps, especially of gram-negative bacteria.  I suggest the “antibiotic resistance” trend that is occurring may be due to increased virulence due to reduced DHEA within the population, especially of this type of bacteria.