A novel simple method for quantifying bacteria from endotracheal aspirates

A convenient dipstrip method (Bacteruritest; Mast Diagnostics) for bacterial quantification was evaluated with 42 endotracheal aspirates. For 31 specimens, the dipstrip method yielded counts within a 10-fold range of surface plate counts. Two specimens yielded counts by the dipstrip within a 100-fold range of plate counts. Six specimens yielded confluent growth at the greatest dilution tested by the dipstrip method, and counts > 10(10) cfu/ml in the surface plate method. Three specimens yielded no detectable growth by the dipstrip and surface plate counts < 10(2) cfu/ml. Dipstrips provide a cheap, convenient method for the routine quantification of the bacterial load in endotracheal aspirates.