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.
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。