TRANSFORM

Infections caused by Stenotrophomonas maltophilia and metallo-β-lactamase (MBL)-producing Enterobacterales are increasingly recognized as critical threats in antimicrobial resistance. S. maltophilia is now the most common carbapenem-resistant Gram-negative pathogen isolated from blood cultures in the United States, with mortality rates exceeding 50% in critically ill and immunocompromised patients.¹ These outcomes are driven by both the vulnerability of the affected population and the lack of effective empiric and definitive treatment options. The organism’s intrinsic resistance to most β-lactams and aminoglycosides, along with limited clinical data supporting any single therapy, has led to uncertainty in treatment selection. Recent guidance recommends combination therapy for serious infections, but the clinical benefit of this approach remains unproven².

Similarly, MBL-producing Enterobacterales pose a growing challenge in the treatment of carbapenem-resistant infections. These organisms are resistant to nearly all β-lactam/β-lactamase inhibitor combinations currently available, leaving few viable options. While agents such as cefiderocol and the combination of ceftazidime-avibactam plus aztreonam (CZA-ATM) show promise, clinical experience is limited, and resistance development remains a concern. The prevalence of MBL-producing organisms is rising in the U.S., yet real-world data on treatment practices and outcomes are sparse.^3,4,5