Galani et al. Activity of Plazomicin against carbapenemase producers resistant included one pandrug-resistant, 10 extensively drug- resistant and two MDR isolates. Those were resistant to tobramycin and amikacin (one was intermediate), whereas ﬁve were or intermediate to gentamicin. None of those isolates was found to carry ribosomal methylases, while 7/13 possessed aminoglycoside modifying enzymes. In four of those isolates aac(69)-Ib was the only gene detected, while aac(39)-Ia and aac(39)-IIa were revealed in one and two isolates respectively. No clear correlation between the MICs of plazomicin and the presence of aminoglycoside-modifying enzymes was observed. Plazomicin MICs against a subset of enterobacterial isolates exhibiting speciﬁc phenotypic characteristics are listed in Table 2. Enterobacterial isolates with plazomicin MICs>8 mg/ml are not common. Landman has reported two E. coli isolates of the same ribotype, from two separate hospitals, in which genes for ribosomal methylases were not detected and the efﬂux pump inhibitor phenyl-arginine-beta-naphthylamide had no appreciable effect on the plazomicin MICs.13 Also 16 isolates with the New Delhi (NDM-1) MBL also producing 16S (rRNA) methylases exhibited high MICs (>8 mg/ml) to plazomicin.4 The low prevalence of 16S rRNA methylases in Enterobacteriaceae that has already been reported,14 as well as the absence of isolates producing the NDM-1 in Greece,15 is most probably the reason why we found no isolates with MICs.4 mg/ml. The next-generation aminoglycoside plazomicin retains activity against all isolates of K. pneumoniae, E. coli, and Enterobacter spp. tested, including those with ESBL, KPC, and VIM-MBL resistance mechan- isms and may represent a promising alternative for the treatment of MDR pathogens. 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