Pastorex® Staph Plus
Performance Characteristics
The performance of Pastorex Staph Plus has been evaluated in several different laboratories. A total of 568 strains of Staphylococcus aureus and 225 staphylococcal strains other than S. aureus were tested with the kit. Culture identification was carried out by using gram stain, catalase activity, and the coagulase tube test. Discrepant samples were subsequently tested by biochemical analysis and by a commercialized alternative rapid test. S. aureus strains were also checked for their susceptibility to methicillin. The results for sensitivity testing on methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA), as well as the total results for all S. aureus strains are reported in Table 1. The results for specificity testing on staphylococcal strains other than S. aureus are reported in Table 2.
Table 1. Performance of Pastorex Staph Plus on MRSA and MSSA Isolates
| | Total | Positive | Negative | Relative Sensitivity |
| MRSA | 295* | 293 | 2 | 99.3% |
| MSSA | 272 | 272 | 0 | 100% |
| Total S. aureus | 567* | 565 | 2 | 99.6% |
* One noninterpretable result was excluded
Table 2. Performance of Pastorex Staph Plus on Other Staphylococcal Strains
| | Total | Positive | Negative | Relative Sensitivity |
| Other Staphylococcal Strains | 225 | 2 | 223 | 99.1% |
A total of 225 staphylococcal isolates other than S. aureus, including S. epidermidis, S. haemolyticus, S. hominis, S. saprophyticus, S. schleiferi, S. lugdunensis, and other species, were also analyzed with Pastorex Staph Plus. A negative result was obtained for 223 of the 225 isolates, as shown in Table 2. The two discrepant results were identified as an S. lugdunensis and an S. hominis strain, and they were also positive with an alternative rapid test.
