TABLE 2.
Performance of the method
| Application criteriona | Probe | Isolated microorganism | nb | Sensitivityc | Specificityd |
|---|---|---|---|---|---|
| Each assay | EUB | All bacteria | 182 | 0.948 | 1.000 |
| Non-EUB | Negative control | 182 | NCe | NC | |
| Gram-positive chains | STREP | Streptococcus mitis | 10 | 1.000 | 1.000 |
| STREP | Streptococcus pyogenes | 3 | |||
| STREP | Streptococcus oralis | 1 | |||
| STREP | Streptococcus dysgalactiae | 1 | |||
| STREP | Streptococcus sanguis | 1 | |||
| STREP | Streptococcus constellatus | 1 | |||
| STREP | Streptococcus agalactiae | 1 | |||
| STREP | Streptococcus milleri | 2 | |||
| EFAEC | Enterococcus faecalis | 10 | 1.000 | 1.000 | |
| Gram-positive clumps | STAUR | Staphylococcus aureus | 13 | 0.667 | 1.000 |
| CoNS | CoNS | 73 | 1.000 | 0.111 | |
| Gram-negative rods | ECOLI | Escherichia coli | 23 | 1.000 | 1.000 |
| PSEUDAER | Pseudomonas aeruginosa | 4 | 1.000 | 1.000 | |
| ENTBAC | Klebsiella pneumoniaef | 12 | 1.000 | 1.000 | |
| ENTBAC | Serratia marcescensf | 4 | |||
| ENTBAC | Proteus mirabilisf | 3 | |||
| ENTBAC | Serratia liquefaciensf | 2 | |||
| ENTBAC | Enterobacter cloaceaef | 2 |
a
The application criterion is the micromorphology of the pathogen by the initial Gram staining which is made after the BacT/Alert blood culture system has detected microbial metabolic activity in the blood sample.
b
n, number of strains positively identified by culturing.
c
Sensitivity is the proportion of blood samples that contain the target organism (confirmed by culturing) and that give a positive result by FISH analysis.
d
Specificity is the proportion of blood samples that do not contain the target organism and that give a negative result (confirmed by culturing) by FISH analysis.
e
NC, not calculated.
f
Bacterial species identified in addition to Escherichia coli, which is also detected with this probe.