Synergistic Effect of Ceftazidime-Avibactam with Meropenem against Panresistant, Carbapenemase-Harboring <i>Acinetobacter baumannii</i> and <i>Serratia marcescens</i> Investigated Using Time-Kill and Disk Approximation Assays

Abstract

Susceptibility of ceftazidime-avibactam and <i>in vitro</i> synergy with meropenem were investigated using disk approximation and time-kill assays against 11 multiresistant <i>Acinetobacter baumannii</i> isolates harboring oxacillinases and 5 <i>Serratia marcescens</i> isolates carrying <i>bla</i>_KPC-2 Ceftazidime-avibactam was very active and synergistic with meropenem against multiresistant <i>S. marcescens</i> isolates. On the other hand, only the <i>A. baumannii</i> isolates coharboring <i>bla</i>_OXA-23 and <i>bla</i>_OXA-117 displayed synergy. The disk approximation technique presented good sensitivity for synergism in <i>S. marcescens</i> infection.