Identification of clinical staphylococcal isolates from humans by internal transcribed spacer PCR

The emergence of coagulase-negativestaphylococcinot only ashumanpathogens but also as reservoirs of antibiotic resistance determinants requires the deployment and development of methods for their rapid and reliableidentification.Internaltranscribedspacer-PCR(ITS-PCR) was used to identify a collection of 617clinicalstaphylococcal isolates. The amplicons were resolved in high-resolution agarose gels and visually compared with the patterns obtained for the control strains of 29 staphylococcal species. Of the 617 isolates studied, 592 (95.95%) were identified byITS-PCRand 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. warneri, 6 of S. simulans, 2 of S. lugdunensis, and 1 each of S. caprae, S. carnosus, and S. cohnii. All species analyzed had uniqueITS-PCRpatterns, although some were very similar, namely, the group S. saprophyticus, S. cohnii, S. gallinarum, S. xylosus, S. lentus, S. equorum, and S. chromogenes, the pair S. schleiferi and S. vitulus, and the pair S. piscifermentans and S. carnosus. Four species, S. aureus, S. caprae, S. haemolyticus, and S. lugdunensis, showed polymorphisms on theirITS-PCRpatterns.ITS-PCRproved to be a valuable alternative for theidentificationofstaphylococci, offering, within the same response time and at lower cost, higher reliability than the currently available commercial systems.