Table 1.
Performance characteristics of the GNR Traffic Light PNA FISH assayg
| Study site | GNR Traffic Light PNA FISH assay result (no. of isolates correctly identified/total no. of isolates [%]) |
Blood culture systeme | |||
|---|---|---|---|---|---|
| Sensitivity |
Specificity of other GNB | ||||
| E. coli | K. pneumoniae | P. aeruginosa | |||
| A | 35/35 | 17/17 | 7/9b | 35/37c | BACTEC |
| B | 31/31 | 30/30 | 11/11 | 36/36 | BacT/Alert |
| C | 87/87 | 54/54 | 16/16 | 62/63d | BACTEC |
| D | 33/33 | 8/9a | 12/12f | 29/29 | VersaTrek |
| Total | 186/186 (100) | 109/110 (99.1) | 46/48 (95.8) | 162/165 (98.2) | |
One false negative for K. pneumoniae was in a mixed culture of E. coli and K. pneumoniae.
Both false negatives were in mixed cultures of P. aeruginosa and K. pneumoniae.
One E. cloacae sample produced a green false positive (negative upon retest), and one A. baumannii sample produced a red false positive.
One false-positive A. radioresistens sample in a mixed culture with Enterococcus faecalis.
A total of 509 blood cultures were tested, including 15 mixed cultures with dual-color PNA FISH results.
Includes 4 spiked samples.
The 95% confidence intervals for E. coli, K. pneumoniae, P. aeruginosa, and other GNB were 98.4 to 100, 95.0 to 99.9, 85.8 to 99.5, and 94.8 to 99.6, respectively.