Microscopic evaluation of sputum specimens submitted for Mycobacterium tuberculosis culture

Using microscopic screening criteria employed in the study of sputum in acute bacterial pneumonia, the authors evaluated 644 sputum samples from 347 patients submitted for mycobacterial bacterial culture. After microscopic examination, these specimens were processed using standard mycobacterial laboratory technics. Salivary specimens accounted for 67.1% of the samples evaluated, and yielded 13 of the total 42 Mycobacterium tuberculosis isolates, as well as 4 of the 21 smear-positive culture-positive specimens. Although specimens from the lower respiratory tract are preferred, specimens of a salivary nature should not be discarded by the Mycobacteriology Laboratory.