TABLE 5.
Prevalence of phenotypic resistance, and correlation between phenotypic antibiotic resistance and presence of genetic resistance markers (genes and mutations) in 113 invasive Hi isolates from 2017, 2020 and 2021, Norway, where both WGS data and AST data were available.
| Group | Drug (n isolates) | Prevalence% (n) | Resistance marker | Resistance marker% (n) | Sensitivity% | Specificity% | PPVa% | NPVb% |
| Beta-lactamsc | Ampicillin (all, n = 113) | 18.6 (21) | blaTEM–1 and/or rPBP3c | 23.0 (26) | 100 | 94.6 | 80.8 | 100 |
| Ampicillin (rPBP3 neg., n = 101) | 13.9 (14) | bla TEM–1 | 13.9 (14) | 100 | 100 | 100 | 100 | |
| Ampicillin (blaTEM–1 neg., n = 98) | 6.1 (6) | rPBP3c | 11.2 (11) | 100 | 94.6 | 54.5 | 100 | |
| Cefuroximed, (n = 113) | 9.7 (11) | rPBP3c | 10.6 (12) | 90.9 | 98.0 | 83.3 | 99.0 | |
| Tetracyclines | Tetracycline (n = 113) | 2.7 (3) | tet(B) | 2.7 (3) | 100 | 100 | 100 | 100 |
| Phenicols | Chloramphenicol (n = 113) | 2.7 (3) | catA2 | 2.7 (3) | 100 | 100 | 100 | 100 |
aPositive predictive value.
bNegative predictive value.
cDefined by the presence of N526K or R517H.
dSusceptible (S) and Susceptible, increased exposure (I) were lumped as “susceptible” in the calculations.