Acetylcysteine increases sensitivity of ceftazidime-avibactam–resistant enterobacterales with different enzymatic resistance to ceftazidime-avibactam in vitro and in vivo

Table 1 Mechanism of CZA resistance and antimicrobial susceptibility of the CZA/NAC combinations against the 8 clinical isolates used in this study

Strain	Antimicrobial resistance mechanism	Antimicrobial susceptibility (MIC, µg/mL)		Antimicrobial combination (MIC, µg/mL)
Strain	Antimicrobial resistance mechanism	CZA	NAC	CZA + NAC	FICI	Potentiation	Interpretation
DC7914	NDM-5	≥ 512/4	≥ 1024	128/4 + 256	≤ 0.5	≥ 4-fold	synergy
DC8439	NDM-1	≥ 512/4	≥ 1024	128/4 + 256	≤ 0.5	≥ 4-fold	synergy
CG1090	NDM-1	≥ 512/4	≥ 1024	128/4 + 256	≤ 0.5	≥ 4-fold	synergy
CG1257	IMP	≥ 512/4	≥ 1024	64/4 + 128	≤ 0.25	≥ 8-fold	synergy
CG1381	OXA-23	≥ 512/4	≥ 1024	128/4 + 128	≤ 0.375	≥ 4-fold	synergy
CG1737	NDM-5	≥ 512/4	≥ 1024	128/4 + 128	≤ 0.375	≥ 4-fold	synergy
FK7018	NDM-1	≥ 512/4	≥ 1024	128/4 + 32	≤ 0.28125	≥ 4-fold	synergy
FK7513	NDM-5	≥ 512/4	≥ 1024	256/4 + 256	≤ 0.75	≥ 2-fold	additive effect/synergy

ISSN: 1471-2180