Table 1. Carbapenem susceptibility and relative level of efflux pump gene expression in P. aeroginosa strains

Ann Clin Microbiol 2020;23:73-80. Killing Dynamics of Carbapenems against Pseudomonas aeruginosa Harboring Varied Determinants of Carbapenem Resistance

Table 1. Carbapenem susceptibility and relative level of efflux pump gene expression in P. aeroginosa strains

P. aeruginosa	MIC (mg/L) of^*		Relative level of expression to A1701_DS^†
P. aeruginosa	Imipenem	Meropenem	MexAB-OprM	MexXY-OprM	MexCD-OprJ
A1701_DS	2	1	1.0	1.0	1.0
B1707_ΔoprD	16	8	0.6	0.3	–^‡
F1709_{pump ↑}	32	32	1.4	0.6	0.7
B1605_{ΔoprD/pump↑IMP}	8	>64	1.6	3.4	2.8

*MICs were determined by broth dilution method. Imipenem and meropenem MICs in quality control strain P. aeruginosa ATCC 27853 were 4 and 0.5 mg/L, respectively.
†The relative level of pump expression was determined for the RND pump genes, mexB for MexAB-OprM, mexY for MexXY-OprM, and mexD for MexCD-OprJ.
‡No mexD gene was identified by PCR.
Abbreviation: MICs, minimal inhibitory concentrations.