Identification of Mycobacterium xenopi by gas chromatography

For the purposes of the following study we cultured 32 strains of Mycobacte rium xenopi isolated from clinical specimens and several strains of other s lowly growing mycobacteria. The cultures were grown in liquid medium and th en analysed - after saponification, methylation, extraction with organic so lvent and washing of the organic phase - using a highly sensitive manual ga s-liquid chromatographic assay for the determination of secondary alcohol 2 -OH-docosanol. The percentage of this compound was compared with that previ ously measured in strains of Mycobacterium xenopi grown on solid medium. Th e presence of this specific alcohol was always apparent, even though its qu antity was lower than that obtained by growing mycobacteria on solid medium . The absence of interference peaks around the compound was checked by anal yzing strains of other slowly growing mycobacteria in the same conditions.