Céline Sakr, Maxime Danjean, Florence Cizeau, David Ducellier, Melissa N Debi, Guilhem Royer, Laurent Poirel, Jean-Winoc Decousser
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引用次数: 0
Abstract
Objectives: Stenotrophomonas maltophilia (Sm) is responsible for infections among immunocompromised and hospitalized patients. Its genomic diversity led to the description of a large complex including numerous genogroups. Regarding acquired resistances, cefiderocol (FDC) is a promising therapeutic option. We aimed to evaluate the the FDC susceptibility of a large panel of Sm strains and explored the genetic support and background of resistance.
Methods: We prospectively collected 154 non-duplicated clinical and environmental strains from five university hospitals between January 2023 and April 2024. All the strains were whole genome sequenced and their genetic background studied using Multi-Locus Sequence Typing (MLST), core genome MLST and genogroup determination. FDC susceptibility was tested using a two steps approach using a marketed product (screening step) and the broth microdilution method (confirmation step). Strains exhibited a MIC > 1 mg/L were considered as non-susceptible (ns). We used a national 2013 strains collection to confirm the resistance of a particular genogroup. The genetic support of FDC non-susceptibility was studied according to a collection of previously selected FDC mutants.
Results: Six out of 154 Sm strains (4%) were non-susceptible to FDC (ns-FDC), including one environmental and five clinical strains. None of the patients was exposed to FDC. The strains belonged to four different ST (ST87, n=2; ST39, n= 2; ST18, n=1, unknown, n=1) but to the same genogroup (genogroup 4). All the seven 2013 genogroup 4 strains were also ns-FDC. None of the previously published mutations/deletions were identified but common non-synonymous mutations were found in tonB and tolQ; a common polymorphism was identified in the promoter region of smet.
Conclusions: The natural intrinsic non-susceptibility of the genogroup 4 could hamper the contribution of FDC for the empiric treatment of Sm infections.
期刊介绍：
Clinical Microbiology and Infection (CMI) is a monthly journal published by the European Society of Clinical Microbiology and Infectious Diseases. It focuses on peer-reviewed papers covering basic and applied research in microbiology, infectious diseases, virology, parasitology, immunology, and epidemiology as they relate to therapy and diagnostics.
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