Outcomes with ceftazidime/avibactam in patients with carbapenem-resistant Pseudomonas infections: a multi-center study

Background: Ceftazidime-avibactam (CAZAVI) is a cephalosporin-beta-lactamase inhibitor combination that is active against Enterobacteriaceae and Pseudomonas aeruginosa that is resistant to other agents, including carbapenems and late-generation cephalosporins. This purpose of this study is to describe the outcomes of patients receiving ceftazidime-avibactam for Pseudomonas infections.

Methods: A retrospective chart review was completed from March 2015 through April 2016 at 3 hospitals in the United States for adult patients who received ceftazidime/avibactam for a Pseudomonas infection. Patients were included if they received CAZAVI for at least 24 hours for a carbapenem-resistant Pseudomonas. Dosage was chosen by providers at individual sites. The primary outcome was in-hospital mortality. Microbiologic and clinical outcomes were also evaluated. Microbiological success required a negative culture at the end of therapy. Clinical success was judged by improved symptoms, improved imaging where relevant, and defervesence.

Results:

Characteristic	Results (N=10)
Male gender, n(%)	7 (70)
Age (median, IQR)	72.5 (70-74.5)
Charlson Comorbidity Index (median, IQR)	6 (4-7.75)
Pitt Bacteremia Score (median, IQR)	2 (0.25-2)
ICU, n(%)	7 (10)
Moderate-severe renal disease	4 (40)
Moderate-severe liver disease	0 (0)
Primary infection, n(%) Pneumonia Bacteremia Urinary tract Intra-abdominal Bone/joint Wound	5 (50) 1 (10) 1 (10) 1 (10) 1 (10) 1 (10)
Hospital day CRE infection diagnosed (median, IQR)	1.5 (1-23)
Hospital day CAZAVI started (median, IQR)	6.5 (2-25)
Patients receiving concomitant therapy for index pathogen, n(%)	5 (50)
Isolates susceptible to CAZAVI, n/N (%)	7/7 (100)
In-hospital mortality, n(%)	2 (20)
Cure or presumed microbiologic cure, n(%)	9 (90)
Clinical success, n(%)	8 (80)

Conclusion: In this severely ill population, 90% of patients had presumed cure, 80% had clinical success, and 80% were alive at the end of their hospital stay. Ceftazidime/avibactam is a potential option for patients with multi-drug resistant organisms causing Pseudomonas infections, including those in intensive care.