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Abstract：
BACKGROUND: Achromobacter spp. are opportunistic pathogens, mostly infecting immunocompromised patients and patients with cystic fibrosis (CF) and considered as difficult-to-treat pathogens due to both intrinsic resistance and the possibility of acquired antimicrobial resistance. Species identification remains challenging leading to imprecise descriptions of resistance in each taxon. Cefiderocol is a broad-spectrum siderophore cephalosporin increasingly used in the management of Achromobacter infections for which susceptibility data remain scarce. We aimed to describe the susceptibility to cefiderocol of a collection of Achromobacter strains encompassing different species and isolation sources from CF or non-CF (NCF) patients.
METHODS: We studied 230 Achromobacter strains (67 from CF, 163 from NCF patients) identified by nrdA gene-based analysis, with available susceptibility data for piperacillin-tazobactam, meropenem and trimethoprim-sulfamethoxazole. Minimal inhibitory concentrations (MICs) of cefiderocol were determined using the broth microdilution reference method according to EUCAST guidelines.
RESULTS: Strains belonged to 15 species. A. xylosoxidans represented the main species (71.3%). MICs ranged from ≤ 0.015 to 16 mg/L with MIC50/90 of ≤ 0.015/0.5 mg/L overall and 0.125/2 mg/L against 27 (11.7%) meropenem-non-susceptible strains. Cefiderocol MICs were not related to CF/NCF origin or species although A. xylosoxidans MICs were statistically lower than those of other species considered as a whole. Considering the EUCAST non-species related breakpoint (2 mg/L), 228 strains (99.1%) were susceptible to cefiderocol. The two cefiderocol-resistant strains (A. xylosoxidans from CF patients) represented 3.7% of meropenem-non-susceptible strains and 12.5% of MDR strains.
CONCLUSIONS: Cefiderocol exhibited excellent in vitro activity against a large collection of accurately identified Achromobacter strains, irrespective of species and origin.
METHODS: We studied 230 Achromobacter strains (67 from CF, 163 from NCF patients) identified by nrdA gene-based analysis, with available susceptibility data for piperacillin-tazobactam, meropenem and trimethoprim-sulfamethoxazole. Minimal inhibitory concentrations (MICs) of cefiderocol were determined using the broth microdilution reference method according to EUCAST guidelines.
RESULTS: Strains belonged to 15 species. A. xylosoxidans represented the main species (71.3%). MICs ranged from ≤ 0.015 to 16 mg/L with MIC50/90 of ≤ 0.015/0.5 mg/L overall and 0.125/2 mg/L against 27 (11.7%) meropenem-non-susceptible strains. Cefiderocol MICs were not related to CF/NCF origin or species although A. xylosoxidans MICs were statistically lower than those of other species considered as a whole. Considering the EUCAST non-species related breakpoint (2 mg/L), 228 strains (99.1%) were susceptible to cefiderocol. The two cefiderocol-resistant strains (A. xylosoxidans from CF patients) represented 3.7% of meropenem-non-susceptible strains and 12.5% of MDR strains.
CONCLUSIONS: Cefiderocol exhibited excellent in vitro activity against a large collection of accurately identified Achromobacter strains, irrespective of species and origin.
摘要：
背景：无色杆菌属。是机会性病原体，主要感染免疫功能低下患者和囊性纤维化（CF）患者，由于固有耐药性和获得性抗菌素耐药性的可能性，被认为是难以治疗的病原体。物种鉴定仍然具有挑战性，导致对每个分类单元中的抗性描述不精确。头孢多醇是一种广谱铁载体头孢菌素，越来越多地用于治疗嗜酸性杆菌感染，其敏感性数据仍然很少。我们旨在描述一组包含CF或非CF（NCF）患者的不同物种和分离来源的无色杆菌菌株对头孢地洛的敏感性。
方法：我们研究了230株无色杆菌菌株（来自CF，来自NCF患者的163）通过基于nrdA基因的分析鉴定，根据哌拉西林他唑巴坦的药敏数据，美罗培南和甲氧苄啶-磺胺甲恶唑。根据EUCAST指南，使用肉汤微量稀释参考方法确定头孢地洛的最低抑制浓度（MIC）。
结果：菌株属于15种。A.xylosoxidans代表了主要物种（71.3％）。MIC范围为≤0.015至16mg/L，MIC50/90总体≤0.015/0.5mg/L，而27个（11.7％）美罗培南非敏感菌株为0.125/2mg/L。头孢地醇的MIC与CF/NCF的起源或物种无关，尽管木氧氧曲霉的MIC在统计学上低于整体上认为的其他物种的MIC。考虑到EUCAST非物种相关断点（2mg/L），228株(99.1%)对头孢地洛敏感。两种头孢地洛耐药菌株(A.CF患者的xylosoxidans）占美罗培南非易感菌株的3.7％和MDR菌株的12.5％。
结论：头孢地洛对大量准确鉴定的无色杆菌菌株表现出优异的体外活性，不论物种和起源。
方法：我们研究了230株无色杆菌菌株（来自CF，来自NCF患者的163）通过基于nrdA基因的分析鉴定，根据哌拉西林他唑巴坦的药敏数据，美罗培南和甲氧苄啶-磺胺甲恶唑。根据EUCAST指南，使用肉汤微量稀释参考方法确定头孢地洛的最低抑制浓度（MIC）。
结果：菌株属于15种。A.xylosoxidans代表了主要物种（71.3％）。MIC范围为≤0.015至16mg/L，MIC50/90总体≤0.015/0.5mg/L，而27个（11.7％）美罗培南非敏感菌株为0.125/2mg/L。头孢地醇的MIC与CF/NCF的起源或物种无关，尽管木氧氧曲霉的MIC在统计学上低于整体上认为的其他物种的MIC。考虑到EUCAST非物种相关断点（2mg/L），228株(99.1%)对头孢地洛敏感。两种头孢地洛耐药菌株(A.CF患者的xylosoxidans）占美罗培南非易感菌株的3.7％和MDR菌株的12.5％。
结论：头孢地洛对大量准确鉴定的无色杆菌菌株表现出优异的体外活性，不论物种和起源。
