Table 4 Assessment of ISFET false negative results through prolonged measurements and comparisons with RAPIDEC CARBA NP (ISFET true positives and true negatives included).
Isolate | β-lactamases | ISFET result (at 30 min) | ΔV80 min (mV) | tΔV < − 10 mV (min) | CARBA NP result/color |
|---|---|---|---|---|---|
E. coli LAR548 | KPC-2 | Positive | NP | 1 | Positive/Yellow |
K. pneumoniae LA28 | NDM-1/CTX-M | Positive | NP | < 1 | Positive/Yellow |
K. pneumoniae LA30 | VIM/CMY | Positive | NP | < 1 | Positive/Yellow |
P. mirabilis 2530 | VIM-1/CMY-16 | Negative | − 17 | 62 | Positive/Orange |
P. mirabilis 11,173 | VIM-1/CMY-16 | Negative | NP | NA | Positive/Yellow |
P. mirabilis EYG92 | VIM-1/CMY-16 | Negative | NP | NA | Positive/Orange |
K. pneumoniae LA-47 | OXA-48/CTX-M | Negative | − 60 | 45 | Positive/Orange |
K. pneumoniae LA-478 | OXA-48/CTX-M | Negative | − 28 | 51 | Positive/Orange |
K. pneumoniae TRK-1 | OXA-48/CTX-M | Negative | − 2 | NA | Negative/Red |
K. pneumoniae TRK-2 | OXA-48/CTX-M | Negative | − 12 | 76 | Positive/Orangea |
K. pneumoniae TRK-5 | OXA-48/CTX-M | Negative | − 5 | NA | Negative/Red |
K. pneumoniae EY-205 | CMY-36/SHV-5 | Negative | − 2 | NA | Positive/Orangea |
K. pneumoniae 17,829 | CTX-M-15/SHV-12 | Negative | 5 | NA | Positive/Orangea |
K. aerogenes EY-25 | LAT-2/SHV-5 | Negative | 15 | NA | Negative/Red |
E. cloacae EY 138 | Derepr. AmpC | Negative | NP | NA | Negative/Orangeb |
