>> >In my search for dates I cam up with this gem.    I am too busy to read 
>> >it properly, but it looks good.  Enjoy.

> It is conceivable that a similar phenomenon may arise in 
> American-foulbrood-infected larvae receiving sulfa drugs since it has been 
> mentioned earlier that strains of B. larvae could adapt themselves to a 
> tenfold increase in the amount of the drug. However, this possibility may 
> not be serious owing to the short period of contact of the vegetative 
> cells in the larvae with the drug and to the rapidity with which the 
> adapted organisms may lose their "resistance" on further growth in the 
> absence of the drug."

I noticed that passage in skimming the article and that is why I posted the 
link for discussion.

I have never heard of sulfa resistance becoming an issue in the way that OTC 
resistance did.  Does anyone recall reports of such a thing?  I inspected 
bees during that period and never heard of it emerging in practice.  Perhaps 
it was because OTC was also in use at the time also?

I might add that OTC was typically used as a routine treatment in hives in 
that period, although not necessarily applied at the same time as sulfa. 
OTC was the recommended control in Alberta, but sulfa was in widespread use 
and sold by bee supply dealers, sometimes in drums of premixed sugar syrup 
from the East.

OTC was typically dusted in spring for EFB and AFB although we often fed it 
in syrup as well.  We were aware of the short lifespan of OTC in syrup, but 
for whatever reason, it was effective.  Maybe the metabolites of breakdown 
in syrup were also active against AFB?  Dunno,  Sulfa was only used in 
syrup.

> This is my point exactly about the misuse of OTC patties by constant 
> application.  This did not allow selective pressure against against any 
> resistant mutants, when they needed to compete against "wild types."

Please get over repeating that one moot point which nobody contests (because 
nobody knows or really cares) and discuss the fact that we did not see OTC 
resistance until sulfa was no longer used and that OTC resistance is no 
longer an issue now that we have Tylan available?  (Consider why Tylan was 
made available...)

Sulfa was used in "constant application", yet AFAIK, resistance to sulfa was 
never a problem.  I am not sure when OTC began to be used.  That was before 
my time, but if sulfa resistance was likely, then I am thinking that the use 
of OTC prevented sulfa resistance and sulfa prevented OTC résistance, just 
as the use of Tylosin has apparently made OTC resistance an non-issue.

I have been trying to find out exactly when sulfa was "banned" and it seems 
to me that it was not banned so much as that buyers and authorities began to 
lower the MRLs.  Detection methods got far more sensitive and after 
truckloads of honey were destroyed or pronounced unsaleable due to sulfa 
content, beekeepers simply stopped using it.  As time passed, authorities 
became more specific in stating which antibiotics were permitted and which 
were prohibited and enforcement increased,  moving from a very permissive 
environment to what we see today.

> "To many beekeepers, the announcement of the preventive properties, often 
> perverted to "curative properties," of sulfa drugs for American foulbrood 
> was the answer to the problem. Before long, however, with the repeated 
> observation of disease recurrence after sulfa drug treatment, it was 
> realized that considerable caution was required in the use of these drugs, 
> that they did not cure an infected colony since they did not kill the 
> spores of B. larvae, that indiscriminat and careless use and undue 
> reliance on their effectiveness might result in masking the disease and in 
> disseminating it widely, and that their application at the wrong,  part of 
> the season was not only ineffective but also resulted often in the 
> contamination of market honey with small but detectable traces of the 
> drugs."

This is pretty much what we have been discussing here.  Back in the 70's 
meeting presentations were titled "Living with AFB" and people said that 
controlling AFB with drugs was like having a tiger by the tail.  Nobody 
thought sulfa was a cure.

> This sounds a little different than the nostalgic waxing recently posted 
> about the use of sulfa.

If anyone considers a look at history as "nostalgic waxing", what that 
person is reading is not what I am writing.   Nobody wants sulfa back in 
use.  We are looking at the history of AFB resistance and the circumstances 
under which it became a problem -- and when it ceased to be a problem -- and 
speculating as to why.  As Santayana pointed out, a look at history can be 
instructive.

These days, conventional understanding is being turned on its head so we 
need to examine our cherished notions and "common knowledge" and move beyond 
simplistic notions.

I'd appreciate any new ideas anyone can bring to this issue.  I think we 
have beaten the old ones to death. 

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