P-1503. Dual β-Lactam Approach for Treatment of Mycobacterium abscessus Infections in Adults – Results in 19 Patients

Of the 19 patients (mean age: 54 years; 68% females), 11 (58%) had undergone solid organ transplantation or had cancer, and 6 (32%) were on immunosuppressants for autoimmune diseases. Pulmonary infections predominated (68%), with 47% of isolates were macrolide resistant. 11 patients (58%) were due to subspecies abscessus. The Dβs most frequently used for treatment were imipenem combined with either amoxicillin (31%) or ceftaroline (26%). Successful clinical cure or stable culture conversion with ongoing treatment was observed in 9 (47%) cases. 4 patients died during treatment. We observed a trend towards shorter times before initiation of Dβ treatment among patients who were cured. Time to initiation of Dβ therapy exceeded 90 days in 3 of 4 patients who died. Eighteen of 19 patients tolerated dual β-lactams therapy well. Among the 5 who discontinued treatment, the multi-drug regimen, not specifically the dual β-lactams, was the likely cause

Treatment with Dβ-containing regimens was associated with higher cure rates in this cohort of severely ill, immunocompromised patients. Earlier treatment correlated with better outcomes. Given the poor response to current treatment regimens and the initial promising results of Dβ therapy, clinical trials are planned. Finally, the chosen Dβs may not fully represent the optimal selection due to patient-driven preferences, possibly underscoring a conservative rather than optimal treatment outcome.

All Authors: No reported disclosures