Demonstration of tlic Bacterium in Tissue by a Modification of the Dieterie Silver Impregnation Stain 



We should mention tliat stained organisms may fade unpredictably. Although some of our 

 slides have retained the stain for over a year, others have faded within hours— especially if they 

 were not coverslipped immediately after staining. 



We have had some success in preventing this fading by modifying the staining procedure as 

 follows; 



(1) After the distilled water rinse in step 111. dip the slides in a lO't solution of 88% 

 formic acid. 



(2) Rinse the slides once in distilled water and then proceed with step 13. 



We have not been able to stain Zenkers'-fixed material successfully: otlier metal-containing 

 fixatives may also adversely affect the staining of organisms. 



To determine whether tissues subjected to decalcification solutions could be successfully 

 stained, we used some tissue that had been treated with our routine decalcification solution 

 (equal parts of 5'/i formic acid and 5% Fomialin) and other tissue treated with a commercial 

 decalcification solution (RDO from Dupage Kinetic Laboratories). Staining was not affected by 

 either decalcification procedure. 



As previously stated, a known Dieterie positive control sHde should be stained in each rack 

 of tissue sections. Control tissue for this procedure is available from the Center for Disease 

 Control. Attention: Mrs. Pat Greer. MT (ASCP). Control Tissue Repository, Bureau of Labora- 

 tories, Atlanta. Georgia 30333. 



ji 



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f. 



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Figure 1. Legionnaires' disease bacteria in an area of consolidation. (Dieterie silver iinpregnation stain, X1500j. 



108 



