Table 1. -Comparison of diagnostic methods on 250 suspected tuberculous submissions 





\() smi 



•ar 



AO tissue 

 section 



NF tissue 

 section 



Histopathology 

 cases 



Mycobacterial 

 culture 





+ 





+ 



+ 



68 



2 51/67 





+ 





+ 



- 



48 



35/47 





+ 





- 



+ 



1 



1/1 





- 





+ 



+ 



5 



2/5 





+ 





- 



- 



15 



11/14 





- 





+ 



- 



6 



3/6 





- 





" 



+ 





 107 



0/0 

 11/80 



Total 



132+ 



118- 



127+ 123- 



74+ 176- 



250 



114/220 



+ Acid-fact bacilli demonstrated. 

 - No acid-fast bacilli demonstrated. 

 Some specimens were not cultured from mycobacteria (not received or previously diagnosed by 

 histopathology procedures as Coccidioidomycosis). 



2 Number of isolations/number of specimens cultured. 



V >-stained smears than in AO-stained sections but the difference was not significant (p. <. 01). Mycobacteria were 

 cultured from 114 of 220 specimens examined. Types isolated included M. bovis (43), U. avium (49), 

 M. paratubrrculosis ( 1 ). Run) an's Group 111 (13) and Runyan's Group IV (5). 



Discussion 



Heavily encapsulated, extensively mineralized lesions from tuberculous cattle often contain lew detectable 

 acid-last organisms. This seems to be especiall) true in an M. bovis infection and trying to find the bacillus in such 

 tissue sections can be a laborious, time-consuming process. This study was designed to determine if any procedure, or 

 combination of procedures, might be superior to conventional fuchsin staining tor demonstrating mycobacteria. 



The \( )-stained smear and the A< )-stained tissue section combination was superior in that acid-last bacilli were 

 found in all specimens that were positive bv an\ of the three staining procedures. The AO-stained smear and the 

 NT-stained tissue section failed to detect acid-fast organisms in six specimens that were positive on AO-stained 

 section. 



In general, fluorescent microscopv methods using AO-stained preparations were easier to interpret and look 

 less time than using light microscopy for NF-stained sections. In addition, the variety of types isolated indicate that 

 the AO-staining procedures are an efficient method for demonstrating mycobacteria. 



REFERENCES 



1. Henry, R.J. and Cassidy, 1). R.: Rapid Decalcification Followed by a New I'uchsin-Methylene Blue Stain for 

 Acid-Fast Bacilli in Frozen Sections. Stain Technology, Vol. 41. No. 6, p. 34 r ). 1066. 



2. Mote. R. F., Mulim. R. I., and McDaniel, H. A.: Detection of Acid-Fast Bacilli in Auramine Stained Smear 

 Preparations. Developmental Studies and Laboratory Investigations, APHIS 91-2, Ma\ , 1972. 



3. , Gigstad, I). C. and Muhm, R. L. (Unpublished fluorescent tissue procedure.) 



2f. 



