mle.stepwise versus step/stepAIC

Hello,

I have a question pertaining to the stepwise regression which I am trying to 
perform.  I have a data set in which I have 14 predictor variables 
accompanying my response variable.  I am not sure what the difference is 
between the function "mle.stepwise" found in the wle package and the 
functions "step" or "stepAIC"?  When would one use "mle.stepwise" versus 
"step/stepAIC"?  Other than the references in the R-software, is there 
anything which discusses the use of "mle.stepwise"?

Thank you kindly in advance for any insight offered.

Jim Brindle