Identification of clinical staphylococcal isolates from humans by internaltranscribed spacer PCR

The emergence of coagulase-negative staphylococci not only as human pathoge ns but also as reservoirs of antibiotic resistance determinants requires th e deployment and development of methods for their rapid and reliable identi fication. Internal transcribed spacer-PCR (ITS-PCR) was used to identify a collection of 617 clinical staphylococcal isolates. The amplicons were reso lved in high-resolution agarose gels and visually compared with the pattern s obtained for the control strains of 29 staphylococcal species. Of the 617 isolates studied, 592 (95.95%) were identified by ITS-PCR and included 11- species: 302 isolates of Staphylococcus epidermidis, 157 of S. haemolyticus , 79 of S. aureus, 21 of S. hominis, 14 of S. saprophyticus, 8 of S. warner i, 6 of S. simulans, 2 of S. lugdunensis, and 1 each of S. caprae, S. carno sus, and S. cohnii. All species analyzed had unique ITS-PCR patterns, altho ugh some were very similar, namely, the group S. saprophyticus, S. cohnii, S. gallinarum, S. xylosus, S. lentus, S. equorum, and S. chromogenes, the p air S. schleiferi and S. vitulus, and the pair S. piscifermentans and S. ca rnosus. Four species, S. aureus, S. caprae, S. haemolyticus, and S. lugdune nsis, showed polymorphisms on their ITS-PCR patterns. ITS-PCR proved to be a valuable alternative for the identification of staphylococci, offering, w ithin the same response time and at lower cost, higher reliability than the currently available commercial systems.