Effective strategies for managing trimethoprim-sulfamethoxazole and levofloxacin-resistant Stenotrophomonas maltophilia infections: bridging the gap between scientific evidence and clinical practice

Purpose of review To discuss the therapeutic options available for the management of difficult-to-treat strains of Stenotrophomonas maltophilia ( Sma ), namely those resistant to trimethoprim-sulfamethoxazole and fluoroquinolones. Recent findings Recent pharmacological studies have highlighted the fact that current breakpoints for first-line antibiotics against Sma are too high. In light of these data, it is likely that the prevalence of difficult-to-treat (DTR) Sma is underestimated worldwide. Two promising alternatives for treating DTR strains are cefiderocol and the combination of aztreonam and an L2 inhibitor. However, clinical trials are currently very limited for these antibiotics and no comparative studies have been carried out to date. It is important to note that the clinical efficacy of cefiderocol appears to be inferior to that initially anticipated from in-vitro and animal studies. Consequently, minocycline and ceftazidime may remain viable options if they are used against strains with a low minimum inhibitory concentration. We advise against the use of intravenous polymyxins and tigecycline. Finally, recent literature does not support the systematic use of combination therapy or long-course treatments. In the coming years, phage therapy may become a promising approach against DTR Sma infections. Summary Overall, clinical comparative studies focused on DTR strains are required in order to provide more accurate and actionable information for therapeutic decisions.