MALDI-TOF typing of Serratia marcescens, Klebsiella oxytoca, and Citrobacter freundii for fast discrimination of isolates during outbreaks. MALDI-TOF typing of Serratia marcescens, Klebsiella oxytoca, and Citrobacter freundii for fast discrimination of isolates during outbreaks

MALDI-TOF mass spectrometry (MS) was evaluated for strain-specific typing of Serratia marcescens, Klebsiella oxytoca VIM, and Citrobacter freundii VIM. The results were compared with next generation whole genome sequencing (WGS) analysis. A collection of 21 S. marcescens, 10 K. oxytoca, and 14 C. freundii isolates were sequenced by WGS using a MiSeq instrument (Illumina, San Diego, CA, USA) and Ridom SeqSphere software (Ridom GmbH, Münster, Germany). For MALDI-TOF analysis bacterial colonies were measured on a Vitek MS system (bioMerieux and clustered using SARAMIS software. Compared to WGS the resolution of MALDI-TOF spectra is lower but the data of this study suggest that MS analysis can be applied in a local setting as a screening method for the early identification of nosocomial outbreaks in high-risk wards.

本研究评估了基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）对黏质沙雷氏菌、产酸克雷伯菌VIM型及弗氏柠檬酸杆菌VIM型的菌株分型效能。将其检测结果与下一代全基因组测序（WGS）分析结果进行对比。本研究共收集21株黏质沙雷氏菌、10株产酸克雷伯菌及14株弗氏柠檬酸杆菌分离株，采用MiSeq测序仪（Illumina公司，美国加利福尼亚州圣地亚哥）与Ridom SeqSphere软件（Ridom有限公司，德国明斯特）完成全基因组测序。针对基质辅助激光解吸电离飞行时间质谱分析，研究人员使用Vitek MS质谱系统（生物梅里埃公司）对细菌菌落进行检测，并通过SARAMIS软件完成聚类分析。与全基因组测序相比，基质辅助激光解吸电离飞行时间质谱的图谱分辨率较低，但本研究数据表明，该质谱分析可在本地场景中作为筛查方法，用于早期识别高危病房内的医院感染暴发事件。