Comparison of strip and Ziehl-Neelsen methods for staining acid-fast bacteria

The efficiency of the Ziehl-Neelsen method for staining acid-fast bacteria was compared with that of the strip-staining procedure in which one kind of impregnated strip is used to stain the bacteria and another kind for simultaneous decolorization and counter-staining of the smear. The methods were evaluated in 1 136 duplicate smears prepared from digested sputum and 307 pairs of direct smears. The efficiency of the strip method was comparable to that of the Ziehl-Neelsen method with digested sputum; with direct smears, however, it generally depended on the quality of the smear. With thick, uneven smears, lower bacterial counts were obtained by strip staining. On the basis of this trial, the authors suggest improvement of the strip method.