Error querying table in multiple databases

I am trying to query the same table in multiple databases.  When my code attempts to query the second database in my list I get the following error:
        Datasource DB1 could not be found.

If I change the order in my DSNList my code always fails at the second database.  

<cfset DSNList = "db1, db2, db3">

<cfloop list="#DSNList#" index="defDSN" delimiters=",">
	<cfoutput>
	[#defDSN#]:
	</cfoutput>
	<CFQUERY NAME="getCategory" DATASOURCE="#defDSN#">
		SELECT      *
		FROM        thread_categories
	</cfquery>
	
	<br />
</cfloop>

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