Browsing by Author "Hujer, Kristine M"
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Item Open Access Can ceftazidime/avibactam and aztreonam overcome β-lactam resistance conferred by metallo-β-lactamases in Enterobacteriaceae?(Antimicrob Agents Chemother, 2017-02-06) Marshall, Steven; Hujer, Andrea M; Rojas, Laura J; Papp-Wallace, Krisztina M; Humphries, Romney M; Spellberg, Brad; Hujer, Kristine M; Marshall, Emma K; Rudin, Susan D; Perez, Federico; Wilson, Brigid M; Wasserman, Ronald B; Chikowski, Linda; Paterson, David L; Vila, Alejandro J; van Duin, David; Kreiswirth, Barry N; Chambers, Henry F; Fowler, Vance G; Jacobs, Michael R; Pulse, Mark E; Weiss, William J; Bonomo, Robert ABased upon knowledge of the hydrolytic profile of major β-lactamases found in Gram negative bacteria, we tested the effectiveness of the combination of ceftazidime/avibactam (CAZ/AVI) with aztreonam (ATM) against carbapenem-resistant enteric bacteria possessing metallo-β-lactamases (MBLs). Disk-diffusion and agar based antimicrobial susceptibility testing were initially performed to determine the in vitro efficacy of a unique combination of CAZ/AVI and ATM against 21 representative Enterobacteriaceae isolates with a complex molecular background that included blaIMP, blaNDM, blaOXA-48, blaCTX-M, blaAmpC, and combinations thereof. Time-kill assays were conducted, and the in vivo efficacy of this combination was assessed in a murine neutropenic thigh infection model. By disk diffusion assay, all 21 isolates were resistant to CAZ/AVI alone, and 19/21 were resistant to ATM. The in vitro activity of CAZ/AVI in combination with ATM against diverse Enterobacteriaceae possessing MBLs was demonstrated in 17/21 isolates, where the zone of inhibition was ≥ 21 mm. All isolates demonstrated a reduction in CAZ/AVI agar dilution MICs with the addition of ATM. At 2 h, time-kill assays demonstrated a ≥ 4 log10 CFU decrease for all groups that had CAZ/AVI plus ATM (8 μg/ml) added, compared to the CAZ/AVI alone group. In the murine neutropenic thigh infection model, an almost 4 log10 reduction in CFUs was noted at 24 h for CAZ/AVI (32 mg/kg q8h) plus ATM (32 mg/kg q8h) vs. CAZ/AVI (32 mg/kg q8h) alone. The data presented herein, requires us to carefully consider this new therapeutic combination to treat infections caused by MBL-producing Enterobacteriaceae.