TABLE 2.
Resolution of monomicrobial blood culture broths with discrepant results
| Target | No. of broth cultures | Results with (no. of isolates): |
Initial call (no. of broth cultures)c | Resolved call (no. of broth cultures)d | ||
|---|---|---|---|---|---|---|
| BC-GNa | Culture | Sequence analysisb | ||||
| E. coli | 1 | E. coli + K. pneumoniae | K. pneumoniae | E. coli/Shigella sp. | FP | TP |
| 1 | E. coli + Enterobacter sp. | Enterobacter sp. | E. coli/Shigella sp. | FP | TP | |
| 1 | E. coli | K. oxytoca | E. coli/Shigella sp. | FP | TP | |
| 1 | E. coli + Proteus sp. | P. mirabilis | ND | FP | ND | |
| 1 | E. coli + K. oxytoca | K. oxytoca | E. coli/Shigella sp. | FP | TP | |
| 1 | E. coli | No growthe | ND | FP | ND | |
| K. pneumoniae | 24 | ND | K. pneumoniae | K. variicola | FN (24) | TN (24) |
| 1 | Enterobacter sp. | K. pneumoniae | K. variicola | FN | TN | |
| 1 | K. pneumoniae | Enterobacter sp. | K. variicola | FP | FP | |
| 1 | ND | K. pneumoniae | K. pneumoniae | FN | FN | |
| K. oxytoca | 1 | E. coli | K. oxytoca | E. coli | FN | TN |
| 1 | K. pneumoniae + K. oxytoca | K. pneumoniae | K. pneumoniae | FP | FP | |
| 6 | K. oxytoca | R. planticola | Raoultella planticola (1), Raoultella ornithinolytica (4), ND (1) | FP (6) | FP (5), ND (1) | |
| 1 | ND | K. oxytoca | K. variicola | FN | TN | |
| 1 | ND | K. oxytoca | K. oxytoca | FN | FN | |
| Enterobacter spp. | 2 | Enterobacter spp. + K. pneumoniae | K. pneumoniae | K. pneumoniae | FP (2) | FP (2) |
| 1 | Enterobacter sp. | K. pneumoniae | K. variicola | FP | FP | |
| 2 | Enterobacter spp. | No growth | ND (2) | FP (2) | ND (2) | |
| 1 | K. pneumonia + Enterobacter sp. | K. pneumoniae | K. pneumoniae | FP | FP | |
| 1 | K. pneumoniae | E. cloacae | K. variicola | FN | TN | |
| P. aeruginosa | 2 | ND | P. aeruginosa | P. aeruginosaf | FN (2) | FN (2) |
| 1 | P. aeruginosa | No growth | ND | FP | ND | |
| Proteus spp. | 2 | Proteus spp. | No growth | ND (2) | FP (2) | ND (2) |
| Acinetobacter sp. | 1 | Acinetobacter sp. | Alcaligenes faecalis | ND | FP | ND |
| 1 | Acinetobacter sp. | Cupriavidus pauculus | A. baumanniif | FP | TP | |
| 1 | ND | A. baumannii | A. baumanniif | FN | FN | |
| Citrobacter sp. | 1 | Citrobacter sp. | Serratia marcescens | S. marcescens | FP | FP |
a
“+” indicates positivity for both species by the BC-GN assay.
b
A slash indicates that the BC-GN assay cannot differentiate between the two species.
c
BC-GN result compared to reference culture.
d
BC-GN result compared to bidirectional sequence analysis. ND, not determined, as specimen was unavailable for sequence analysis.
e
No growth, Gram-negative bacilli observed in primary Gram stain of blood culture.
f
Identification confirmed by MALDI-TOF MS.