Table 1. New antibiotics for multidrug-resistant Gram-negative bacteria.

Drug	Class	Development stage	Activity	FDA indication
Aztreonam/avibactam	Monobactam/β-lactamase inhibitor	Phase II	ESBL, KPC, class C β-lactamase, MBL	Not applicable
Cefiderocol	Siderophore cephalosporin	Phase III	ESBL, CRE (class A, B, and D enzymes), carbapenem-resistant Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter baumannii	Not applicable
Ceftazidime/avibactam	Cephalosporin/β- lactamase inhibitor	FDA-approved	ESBL, KPC, AmpC, some class D serine β-lactamases	HABP/VABP, cIAI, cUTI
Ceftolozane/tazobactam	Cephalosporin/β- lactamase inhibitor	FDA-approved	ESBL, MDR P. aeruginosa	cUTI, cIAI
Delafloxacin	Fluoroquinolone	FDA-approved	Klebsiella pneumoniae, including AmpC and class A ESBL-producers, ciprofloxacin-resistant Escherichia coli and A. baumannii	ABSSSI
Eravacycline	Fluorocycline tetracycline	FDA-approved	ESBL, CRE, MDR A. baumannii	cIAI
Imipenem+cilastatin/ relebactam	Carbapenem/β-lactamase inhibitor	Phase III	KPC, MDR P. aeruginosa	Not applicable
Meropenem/vaborbactam	Carbapenem/boronic acid inhibitor	FDA-approved	CRE (class A and C enzymes)	cUTI
Murepavadin	Cyclic peptide that targets outer membrane	Phase III	MDR P. aeruginosa	Not applicable
Omadacycline	Aminomethylcycline	FDA-approved	ESBL, A. baumannii	ABSSSI, CABP
Plazomicin	Aminoglycoside	FDA-approved	ESBL, CRE excluding NDM producers, A. baumannii, P. aeruginosa	cUTI

ABSSSI, acute bacterial skin and skin structure infection; CABP, community-acquired bacterial pneumonia; cIAI, complicated intra-abdominal infection; CRE, carbapenem-resistant Enterobacteriaceae; cUTI, complicated urinary tract infection; ESBL, extended-spectrum β-lactamase; FDA, US Food and Drug Administration; HABP, hospital-acquired bacterial pneumonia; KPC, Klebsiella pneumoniae carbapenemase; MBL, metallo-β-lactamase; MDR, multidrug-resistant; NDM, New Delhi metallo-β-lactamase; VABP, ventilator-acquired bacterial pneumonia.