>>We have heard a number of theories, including blaming extender patties, 
>>however I have never seen any proof.

> However, it appears likely that the constant application of extender 
> patties strongly selected for resistant strains, no matter where they 
> actually obtained the genetic material (by mutation, upregulation, or 
> transferrence of plasmids).  For more info google the title of a free 
> download "Mechanisms of Antimicrobial Resistance in Bacteria"

I still have not seen any proof that extender patties were a cause of the 
problem or even that they exacerbated the problem, and merely speculating 
and saying, "it appears likely" without supporting reasoning and observation 
is merely smoke.  No matter how popular and oft-repeated that claim may be, 
IMO, it does not hold water.

The article provided referred to entirely different situations and does 
nothing to support the speculation.

Moreover, if the bacteria we are discussing were already resistant, and 
application of extender patties merely proved that OTC could not control the 
AFB in more constant dosing, then further selection for greater resistance 
seems to me to rather moot.  Obviously any further use of the antibiotic in 
question by any delivery system would be of doubtful efficacy, especially if 
an ideal delivery method was failing.

How is AFB different from a hospital?  In AFB, each larva is infected 
individually and there are specific hurdles which must be cleared 
individually for each and every larva to be lethally infected.  For example, 
one hurdle is that, AFAIK, one spore cannot achieve a kill by itself and has 
a short window in which to accomplish the task or be extinguished.  Is the 
vegetative stage transferrable in-hive and infective?  I don't know, but I 
have never heard it to be.

Seeing as we are exchanging opinions here, I'll repeat mine: IMO, extender 
patties were part of the solution, not part of the cause.  IMO, chronic 
under-dosing was the cause of most of the selection and concentration of 
resistant bacteria, partly due to the rapid fade characteristic of OTC. 
IMO, higher and more even doses, such as maintained by extender patties 
could well have delayed the emergence of resistant strains. 

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