USE OF PRESUMPTO-PLATES TO IDENTIFY ANAEROBIC-BACTERIA

Identification of anaerobic bacteria requires special media and growth conditions that contribute to a higher cost per identification than t hat for aerobic isolates. Newer rapid methods streamline the identific ation process, but confirmation to the species level is often. difficu lt. The Presumpto Plate method for the identification of commonly enco untered anaerobes consists of three quadrant plates, each containing f our conventional media, that result in the generation of 21 test param eters: growth on Lombard-Dowell medium; production of indole, indole d erivative, catalase, lecithinase, and lipase; proteolysis of milk, H2S , and esculin; growth on 20% bile; precipitate on bile; DNase, glucose , casein, starch, and gelatin hydrolysis; and fermentation of lactose, mannitol, and rhamnose. Identification charts were developed by using the results from 2,300 anaerobic isolates, Because conventional media were used, there was a high degree of agreement between the Presumpto Plate method and the reference method when testing commonly encounter ed anaerobes, The Presumpto Plate method is as accurate as commerciall y available enzyme systems for the identification of many anaerobic sp ecies but is less expensive to perform.