Table 1.

Promising DBO inhibitors in pre-clinical development or FDA approved.

DBO name	Characteristics	References
Avibactam (NXL104)	Currently only FDA approved DBO β-lactamase inhibitor. Partnered with ceftazidime	Reviewed in Coleman, 2011
WCK 4234	Active against Pseudomonas and Acinetobacter Class A, C, and D β-lactamases. Partnered with imipenem or meropenem	Mushtaq et al., 2017
WCK 5107 (Zidebactam)	Active against A. baumannii, Enterobacteriaceae, and Pseudomonas aeruginosa. Dual target inhibitor (P.a. PBP2). Partnered with cefepime or sulbactam	Livermore et al., 2017; Moya et al., 2017a,b; Sader et al., 2017a,b
WCK 5153	Active against A. baumannii and P. aeruginosa. Dual target inhibitor (P.a. PBP2). Partnered with cefepime or sulbactam	Moya et al., 2017a,b
ETX2514	Active against Gram-negative bacteria including A. baumannii and P. aeruginosa. Dual target inhibitor (A. b. PBP2). Partnered with sulbactam	Durand-Réville et al., 2017; McLeod et al., 2017; Shapiro et al., 2017
Relebactam (MK-7655)	Active against Enterobacteriaceae, Klebsiella pneumoniae, and Pseudomonas. Partnered with imipenem	Livermore et al., 2013; Blizzard et al., 2014; Lapuebla et al., 2015; Haidar et al., 2017; Lob et al., 2017
Nacubactam (OP0595)	Active against Enterobacteriaceae, P. aeruginosa, and K. pneumoniae. Dual target activity (inhibits PBP2) and has “enhancer”-activity. Partnered with cefepime, piperacillin, or meropenem	Livermore et al., 2015; Morinaka et al., 2015, 2017