Genomic profiling of #cefotaxime-resistant #Haemophilus influenzae from #Norway and #Sweden reveals extensive expansion of virulent #MDR international clones
Abstract Cefotaxime-resistant Haemophilus influenzae (CRHI) are a global concern, but little is known about their molecular epidemiology . The goal of this study was to perform genomic profiling of 191 CRHI from Norway (n = 183) or Sweden (n = 8) (2006–2018) and assess clonal spread using core genome multilocus sequence typing (cgMLST)-based Life Identification Number (LIN) codes based on whole genome sequencing (Ion Torrent). Cefotaxime resistance was confirmed with broth microdilution minimal inhibitory concentration (MIC), interpreted with the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. 35.7% of isolates with cefotaxime gradient MIC of 0.25 mg/L were falsely resistant. All but two isolates (blood) were non-invasive, and all but two (serotype f) were non-typeable. Characterization included calling of resistance determinants, ftsI typing (penicillin-binding protein 3, PBP3), and classification of PBP3-mediated beta-lactam resistance (rPBP3), with a...