Treatment of Vascular Prosthesis Infections With Ceftazidime-Avibactam After Failure of Initial Therapy With Polymyxin B and Tigecycline: Report of Two Cases

Surgical site infections (SSIs) represent an important cause of morbidity in patients. In cases where multidrug-resistant Gram-negative bacilli are identified, available therapeutic options are limited and frequently associated with toxicity. New beta-lactams with beta-lactamase inhibitors have limited experience in the treatment of SSIs. We describe two clinical cases of SSI treatment after arterial bypass surgery with prosthesis, in which regimens based on Polymyxin B or Tigecycline were used and later replaced by Ceftazidime-Avibactam (CAZ-AVI). Patient 1: Female, 65 years old, type II diabetic, underwent femoral bypass with organic prosthesis for treatment of peripheral obstructive arterial disease (POAD), and evolved with fever and secretion from the periprosthetic surgical wound. Klebsiella pneumoniae sensitive to Polymyxin B and CAZ-AVI was isolated from the surgical wound, with NG-Test® CARBA positive for KPC. After initiation of therapy with Polymyxin B, the patient persisted with fever, leukocytosis, and renal dysfunction. Therapy was switched to CAZ-AVI for 14 days, with improvement of the lesion; however, the prosthesis was retained and the patient was discharged. One month later, the patient returned with persistent secretion, and prosthesis removal with the need for bilateral suprapatellar amputation was performed. Patient 2: Female, 62 years old, underwent iliac bypass with synthetic prosthesis for treatment of POAD. Fifteen days after the procedure, she developed dehiscence, necrosis, and purulent secretion from the incision, with isolation of K. pneumoniae from a tissue fragment, sensitive to Tigecycline, Polymyxin, and CAZ-AVI, with NG-Test® CARBA positive for KPC. Initial treatment with Polymyxin B and Tigecycline was performed for 15 days, without improvement. She progressed with signs of sepsis, periprosthetic collection visualized on imaging, and blood cultures positive for K. pneumoniae with the same sensitivity profile and NG-Test® CARBA positive for KPC. Therapy was switched to CAZ-AVI, with prosthesis removal five days after the regimen change. The patient showed good response after 14 days of therapy, without need for further intervention, and is under outpatient follow-up. Susceptibility to Polymyxin B in both cases was determined by broth microdilution. CAZ-AVI appears to be a viable option for the treatment of SSIs, with lower toxicity. However, adequate control of the infectious focus remains an essential measure for therapeutic success.