embC-embA IGR mutations confer a higher resistance to EMB in clinical strains. pAmt, mutation in embC-embA IGR; Bmt, mutations in embB site 306, 406, or 497; pAwt, wild type in embC-embA IGR; Bwt, wild type in embB site 306, 406, or 497; R, EMB-resistant strains; S, EMB-susceptible strains.