Molecular characterization of macrolide resistance in Haemophilus influenzae and Haemophilus parainfluenzae strains (2018-21).

Macrolide resistance was higher in H. parainfluenzae than in H. influenzae, with differences in the underlying mechanisms. H. parainfluenzae exhibits co-resistance to other antimicrobials, often leading to an extensively drug-resistant phenotype. This highlights the importance of conducting antimicrobial resistance surveillance.