Introduction. The therapeutic options to treat Acinetobacter baumannii infections are very limited. Aim. Our aim was to evaluate the activity of sulbactam combined directly with avibactam or the ampicillin-sulbactam/ceftazidime-avibactam combination against extensively drug-resistant A. baumannii isolates. Methodology. Extensively drug-resistant A. baumannii isolates (n=127) collected at several South American hospitals were studied. Synergy with the sulbactam/avibactam combination was assessed in all isolates using the agar dilution method. Avibactam was used at a fixed concentration of 4 mg l−1. A disc diffusion synergy test was also performed. Synergy by a time-kill experiment was performed in a selected isolate. Results. Synergy with sulbactam/avibactam was demonstrated in 124 isolates and it showed MIC values ≤4 mg l−1. This synergy was not detected in the three New Delhi metallo-β-lactamase-harbouring isolates. Similar results were observed with the disc diffusion synergy test of ampicillin-sulbactam/ceftazidime-avibactam. In the time-kill experiments, sulbactam/avibactam showed a rapid synergistic and bactericidal activity in ampicillin-sulbactam-resistant isolates. Conclusions. This study demonstrated that the sulbactam/avibactam combination displayed synergistic activity against A. baumannii isolates. This synergy was observed when both inhibitors were also used as part of the commercially available combinations: ampicillin-sulbactam and ceftazidime-avibactam.

中文翻译：

---

舒巴坦/ avibactam组合对广泛耐药的鲍曼不动杆菌的体外协同活性。

介绍。治疗鲍曼不动杆菌感染的治疗选择非常有限。目标。我们的目的是评估舒巴坦直接与阿维巴坦或氨苄西林-舒巴坦/头孢他啶-阿维巴坦组合对广泛耐药的鲍曼不动杆菌分离物的活性。方法。研究了南美几家医院收集的广泛耐药的鲍曼不动杆菌菌株（n = 127）。使用琼脂稀释法评估了所有菌株中舒巴坦/阿维巴坦组合的协同作用。阿维巴坦以4 mg l -1的固定浓度使用 。还进行了光盘扩散协同测试。通过时间杀灭实验的协同作用是在选定的分离物中进行的。结果。在124株菌株中证实与舒巴坦/ avibactam有协同作用，MIC值≤4 mg l -1。在三个新德里带有金属β-内酰胺酶的分离株中未发现这种协同作用。氨苄西林-舒巴坦/头孢他啶-avibactam的椎间盘扩散协同试验观察到相似的结果。在时间杀灭实验中，舒巴坦/ avibactam在氨苄西林-耐舒巴坦的分离株中显示出快速的协同和杀菌活性。结论。这项研究表明舒巴坦/ avibactam组合显示出对鲍曼不动杆菌的协同活性。 隔离株。当两种抑制剂也用作市售组合的一部分时，可以观察到这种协同作用：氨苄青霉素-舒巴坦和头孢他啶-avibactam。