Clinical Outcomes of Omadacycline in Critically Ill Patients Treated for Carbapenem-Resistant Organism Infections: A Retrospective Study

Objective: This study aimed to evaluate the efficacy and safety of omadacycline (OMA) for the treatment of carbapenem-resistant organisms (CROs) infections, which are associated with substantial morbidity and mortality and limited therapeutic options. Methods: The patients included were ≥ 18 years old, had CRO-positive cultures, and had been treated with OMA-based combination therapy for ≥ 72 hours. Common clinical comorbidities and markers of disease progression were collected. The primary outcome was 30-day all-cause mortality. The secondary outcomes included 30-day recurrence, resolution of signs and symptoms of infection, 90-day readmission, and OMA-possible adverse events. Results: This study included 132 patients treated with OMA for CRO infections, with a median age of 67 years and a majority of male patients. Of the 132 patients analyzed, 78.8% were admitted to the intensive care unit, with hypertension, diabetes, and chronic pulmonary disease being the most frequent comorbidities. The median Charlson Comorbidity Index (CCI) score for the entire cohort was 5 (interquartile range [IQR], 4– 7), indicating a moderate to high comorbidity burden. Pneumonia represented the predominant infection (84.8%). The overall 30-day mortality rate was 27.3%. In the Carbapenem-Resistant Acinetobacter baumannii (CRAB) cohort (n=89), OMA therapy was initiated promptly following culture confirmation, with a median treatment duration of 8 days. The 30-day mortality rate in this subgroup was 29.2% (26/89). Adverse events included elevated aspartate transaminase (21.3%, 19/89), alanine aminotransferase (18.0%, 16/89), alkaline phosphatase (23.6%, 21/89), blood urea nitrogen (25.8%, 23/89) and decreased fibrinogen levels (18.0%, 16/89). In the Carbapenem-Resistant Klebsiella pneumoniae (CRKP) cohort (n=57), the 30-day mortality rate was 29.8% (17/57), with a safety profile comparable to the CRAB group. Conclusion: The results demonstrated that OMA has promising clinical efficacy against CRAB or CRKP infections in critically ill patients. Infographic on CRO infections, study cohort and key outcomes. Keywords: omadacycline, Carbapenem-resistant Acinetobacter baumannii , carbapenem-resistant Klebsiella pneumoniae , tetracycline