. 2020 May 21;64(6):e00552-20. doi: 10.1128/AAC.00552-20

TABLE 5.

Effects of various concentrations of QPX7728 on biapenem MICs in isogenic OXA-23-producing strains of Acinetobacter baumannii overexpressing efflux pumps

Strain^a	Description	Antibiotic	Antibiotic MIC (μg/ml) in the presence of the following QPX7728 concn (mg/ml)^b:							MIC (μg/ml) for recipient	PV_max^c (μg/ml)
Strain^a	Description	Antibiotic	0	0.25	0.5	1	2	4	8	MIC (μg/ml) for recipient	PV_max^c (μg/ml)
ACM1565	Wild type	Biapenem	32	32	16	2	1	0.06	0.016	0.125	4
ACM1566	AdeIJK overexpressed	Biapenem	16	16	4	2	0.5	0.06	0.06	0.125	4
ACM1567	AdeABC overexpressed	Biapenem	32	32	16	8	0.5	0.06	0.016	0.125	4
ACM1565	Wild type	Meropenem	32	32	16	4	4	0.25	0.03	0.5	4
ACM1566	AdeIJK overexpressed	Meropenem	32	32	32	4	2	2	1	2	2
ACM1567	AdeABC overexpressed	Meropenem	64	64	64	32	1	0.25	0.016	0.5	4

All strains produced OXA-23, the gene for which was carried on a plasmid. Strains ACM1565, ACM1566, and ACM1567 were constructed by conjugating an OXA-producing plasmid from clinical strain AB1387 into rifampin-resistant derivatives of AB1007 (ACM1139, which is a wild-type strain), ACM1027 (ACM1494, which is an adeN mutant overexpressing AdeIJK), and ACM1030 (ACM1495, which is an adeS mutant overexpressing AdeABC), respectively.

Biapenem and meropenem MICs in the presence of QPX7728 at PV_max are in boldface.

PV_max, maximal potentiating value, which is the concentration of QPX7728 that reduces the biapenem or meropenem MIC to the level seen in the parent strain that lacks OXA-23 (corresponding to the complete inhibition of OXA-23).