The Tween 80 reaction does not correlate to triglyceride lipase production of Staphylococcus aureus.

This comparison of Tween 80 reaction with triglyceride lipase production comprises 357 Staphylococcus aureus strains from various clinical sources. Tween 80 is a water-soluble substrate, and thus estimates esterase activity. Lipase production was assayed using water-insoluble substrates (radiolabelled triglyceride emulsions). Only a minor proportion of Tween 80-positive strains had significant triglyceride lipase production (greater than 5 mU/10(9) bacteria). The discrepancy between the two methods was most pronounced in subgroups of samples with low frequency of lipase production, e.g. from isolates from superficial locations such as nasal mucosa and impetigo. Owing to its low specificity, the Tween 80 reaction therefore seems unsuitable as a marker for lipase activity in clinical isolates of Staphylococcus aureus.