Ceftazidime-Avibactam for the Treatment of Carbapenem-Resistant Organisms: A Prospective, Observational, Single-Center Study

Introduction: The World Health Organization has declared carbapenem-resistant organisms a research and development priority. Although ceftazidime–avibactam was approved around a decade ago, there is still a lack of prospective data on the treatment of resistant pathogens with this agent. Methods: We conducted a prospective, observational, single-center, investigator-initiated study of patients treated with ceftazidime–avibactam for infections caused by carbapenem-resistant organisms. The primary outcome was clinical cure 14 days after the initiation of ceftazidime-avibactam treatment. Secondary outcomes, which were assessed on day 30, included microbiological failure, development of resistance, all-cause mortality, and length of stay in the intensive care unit. Results: A total of 50 patients were included in the study. At baseline, the median Charlson Comorbidity Index and Sequential Organ Failure Assessment Score were 5.5 and 7. Approximately three-quarters of the patients were treated in an intensive care unit and had undergone mechanical ventilation within the previous 7 days prior to the commencement of ceftazidime–avibactam treatment. Half of the patients were diagnosed with nosocomial pneumonia. Most infections were caused by Pseudomonas aeruginosa (48%) and Klebsiella pneumonia (28%). Clinical cure at day 14 was achieved in 59% of patients. Four deaths (9%) and two cases of microbiological failure (4%) were observed. The median length of stay in the intensive care unit was 14 days. There was no emergence of resistance to ceftazidime–avibactam. Discussion: Our study contributes to the growing body of evidence supporting the effectiveness of ceftazidime–avibactam in treating infections caused by carbapenem-resistant organisms. In this cohort of critically ill patients, our results in terms of both clinical success and survival are in the upper range compared to those from mainly retrospective and some prospective studies. Although the benefits of ceftazidime–avibactam have been demonstrated in this and other studies, it must be prescribed cautiously to ensure it remains effective.