[Non-pigmented Serratia: utility of hydrolysis of Tween 80 in its identification]

The ability of Serratia sp. to hydrolyze Tween 80 and the usefulness of this test for differentiating it from other Gram negative bacilli was studied, comparing it with the capacity of production of DNAsa by the same strains using the O-Toluidine blue method. The total number of strains assayed was 88. The sensitivity obtained was 83.9% and specificity 91.3%, with a positive predictive value of 83.9% and a negative predictive value of 91.2%. Using this method to differentiate only non-pigmented Serratia from Klebsiella sp. and Enterobacter sp. the sensitivity and specificity obtained was 100%. Concerning the cost, this method proved to be 3.86 times cheaper than the DNAsa one.