Novais Â, Sousa C, de Dios Caballero J, Fernandez-Olmos A, Lopes J, Ramos H, Coque T M, Cantón R, Peixe L
REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
Eur J Clin Microbiol Infect Dis. 2014 Aug;33(8):1391-9. doi: 10.1007/s10096-014-2071-5. Epub 2014 Mar 7.
Reliable, quick and low-cost methods are needed for the early detection of multidrug-resistant and highly virulent high-risk B2 and D Escherichia coli clones or clonal complexes (HiRCC). Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) seems to have a good discriminatory potential at different subspecies levels, but it was never evaluated for the discrimination of E. coli clones. We assessed the potential of MALDI-TOF MS coupled to multivariate data analysis to discriminate representative E. coli B2 and D HiRCC. Seventy-three E. coli isolates from B2 (including ST131 and B2 non-ST131 clones) and D (ST69, ST393, ST405) with variable pulsed-field gel electrophoresis (PFGE) patterns, origins and dates (1980-2010) were tested. MS spectra were acquired from independent extracts obtained from different plate cultures in two different Microflex LT MALDI-TOF devices (Bruker) after a standard extraction procedure. MALDI-TOF MS fingerprinting analysis revealed a good discriminatory ability between the four HiRCC analysed (ST131, ST69, ST405, ST393) and between B2 ST131 and other B2 non-ST131 isolates. Clusters defined by MALDI-TOF MS were consistent with the clonal complexes assigned by multilocus sequence typing (MLST), although differences were detected regarding the composition of clusters obtained by the comparison of PFGE profiles. We demonstrate, for the first time, that characteristic mass fingerprints of different E. coli HiRCC are sufficiently discriminatory and robust to enable their differentiation by MALDI-TOF MS, which might represent a promising tool for the optimisation of infection control, individual patient management and large-scale epidemiological studies of public health relevance. The good correlation between phenotypic and genotypic features further corroborates phylogenetic relationships delineated by MLST.
早期检测多重耐药和高毒力的高风险B2和D型大肠杆菌克隆或克隆复合体（HiRCC）需要可靠、快速且低成本的方法。基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）似乎在不同亚种水平上具有良好的鉴别潜力，但从未对其鉴别大肠杆菌克隆的能力进行过评估。我们评估了MALDI-TOF MS结合多变量数据分析来鉴别代表性大肠杆菌B2和D HiRCC的潜力。测试了73株来自B2（包括ST131和非ST131的B2克隆）和D（ST69、ST393、ST405）的大肠杆菌分离株，这些分离株具有不同的脉冲场凝胶电泳（PFGE）图谱、来源和日期（1980 - 2010年）。在经过标准提取程序后，从两种不同的Microflex LT MALDI-TOF设备（布鲁克）中不同平板培养物获得的独立提取物中获取MS谱图。MALDI-TOF MS指纹分析显示，在所分析的四个HiRCC（ST131、ST69、ST405、ST393）之间以及B2 ST131和其他B2非ST131分离株之间具有良好的鉴别能力。由MALDI-TOF MS定义的聚类与多位点序列分型（MLST）指定的克隆复合体一致，尽管通过比较PFGE图谱获得的聚类组成存在差异。我们首次证明，不同大肠杆菌HiRCC的特征性质量指纹具有足够的鉴别力和稳健性，能够通过MALDI-TOF MS进行区分，这可能是优化感染控制、个体患者管理以及具有公共卫生相关性的大规模流行病学研究的一个有前景的工具。表型和基因型特征之间的良好相关性进一步证实了MLST所描绘的系统发育关系。
