Table 8.
MIC and susceptibility results for M. catarrhalis isolates
| Susceptibility |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MIC (mg/L) |
CLSI |
PK/PD |
EUCAST |
|||||||||
| Antimicrobial | n | 50% | 90% | min | max | %S | %I | %R | %S | %S | %I | %R |
| AMCa | 40 | 0.25 | 0.5 | ≤0.015 | 0.5 | 100 | — | 0 | 100 (100) | 100 | — | 0 |
| Azithromycinb | 33 | 0.12 | 0.5 | 0.03 | 0.5 | NA | — | — | NA | NA | NA | NA |
| Cefaclor | 40 | 1 | 1 | 0.25 | 2 | 100 | 0 | 0 | 32.5 | NA | NA | NA |
| Cefuroxime | 40 | 1 | 1 | ≤0.015 | 2 | 100 | 0 | 0 | 90 | 7.5 | 92.5 | 0 |
| Levofloxacin | 40 | 0.06 | 0.06 | 0.015 | 1 | 100 | — | — | 100 | 100 | — | 0 |
AMC, amoxicillin/clavulanic acid; 50%, concentration required to inhibit 50% of isolates; 90%, concentration required to inhibit 90% of isolates; min, minimum MIC observed; max, maximum MIC observed; S, susceptible; I, intermediate; R, resistant; NA, not applicable; NA, no breakpoint data available (NA for azithromycin because Etest® breakpoints in CO2 not available).
aPK/PD susceptibility at high dose is shown in parentheses.
bAzithromycin QC data were out of range for some MIC batches, so these isolates (n = 7) are not included.