Minimal inhibitory concentrations (µg/ml) of 14 antimicrobials against 18 NTHi isolates using the microdilution method according to CLSI breakpoint criteriaa.

aCLSI: Clinical and Laboratory Standard Institute. Breakpoint Criteria (S, susceptible; I intermediate; R, resistant): AM (Ampicillin; S≤1, I = 2, R≥4); AMC (Amoxicillin-/clavulanic acid; S≤4/2, R≥8/4); CFU (Cefuroxime; S≤4, I = 8, R≥16); CTX (Cefotaxime; S≤2); CRO (ceftriaxone; S≤2); IMI (Imipenem; S≤4); MER (Meropenem; S≤0.5); TET (Tetracycline; S≤2, I = 4, R≥8); CHL (Chloramphenicol; S≤2, I = 4, R≥8); TxS (Trimethoprim/sulfamethoxazole; S≤0.5/9.5, I = 1/19–2/38, R≥4/76); AZI (Azithromycin; S≤4); CIP (Ciprofloxacin; S≤1); LEV (Levofloxacin; S≤2); RIF (Rifampin; S≤1, I = 2, R≥4). Ref CLSI 2013.bβ-lactamase producing isolate.