EVALUATION OF 2 COMMERCIAL SYSTEMS FOR IDENTIFICATION OF COAGULASE-NEGATIVE STAPHYLOCOCCI TO SPECIES LEVEL

Bloodstream (224) and urine (nine) isolates of coagulase-negative stap hylococci (CNS) were evaluated using MicroScan Pos ID and Rapid Pos ID panels. A modification of the conventional method of Kloos and Schlei fer served as the reference method. The isolates were selected to incl ude a broad range of CNS species, including 44 S. epidermidis, 50 S. h ominis, 39 S. warneri, 33 S. capitis, 21 S. haemolyticus, 12 S. simula ns, 11 S. saprophyticus, six S. cohnii, five S. lugdunensis, three S. xylosus, four S. auricularis, two S. schleiferi, two S. intermedius, a nd one S. sciuri. The Pos ID panel had an overall rate of agreement (c orrect plus probably correct) with the reference method of 79%, includ ing 95% for S. epidermidis, 95% for S. haemolyticus, 64% for S. homini s, 67% far S. simulans, 79% for S. warneri, and 100% for S. saprophyti cus. The Rapid Pas ID panel had an overall rate of agreement (correct plus probably correct) of 76%, including 91% for S. epidermidis, 90% f ar S. haemolyticus, 64% for S. hominis, 58% for S. simulans, 77% far S . warneri, and 100% for S. saprophyticus. Both systems are acceptable for the identification of the clinically significant species S. haemol yticus, S. saprophyticus, and S. epidermidis, but are less reliable fo r the infrequently isolated species of CNS.