Observations on paraffin baiting as a laboratory diagnostic procedure in nocardiosis.

Abstract

The efficacy of paraffin bait technique in the isolation ofNocardia asteroides from clinical specimens has been investigated. In a comparative study 1091 clinical specimens, mostly sputa and bronchial aspirates collected from 639 patients of bronchopulmonary diseases and 11 of meningitis, were examined by paraffin baiting and the conventional technique. Thirty-six clinical specimens originating from 12 of the patients yieldedN. asteroides by the paraffin bait technique but only 4 by the conventional technique. Approximately 95 % of 125 sputum samples inoculated withN. asteroides yielded the pathogen by paraffin baiting as against 49 % by the conventional technique. Paraffin baiting was more productive than the conventional technique in the isolation ofN. asteroides from mixed suspensions with a number of fungi and bacteria. It is concluded that paraffin baiting can be profitably adopted as a suitable technique for the isolation ofN. asteroides from clinical specimens, such as, sputum, gastric lavage, etc., which are often contaminated. The technique has no particular advantage with non-contaminated specimens.