De Carolis Elena, Paoletti Silvia, Nagel Domenico, Vella Antonietta, Mello Enrica, Palucci Ivana, De Angelis Giulia, D'Inzeo Tiziana, Sanguinetti Maurizio, Posteraro Brunella, Spanu Teresa
Institute of Microbiology, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy.
Institute of Public Health, Section of Hygiene, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy.
PLoS One. 2017 Oct 5;12(10):e0185935. doi: 10.1371/journal.pone.0185935. eCollection 2017.
Nowadays, the global spread of resistance to oxyimino-cephalosporins in Enterobacteriaceae implies the need for novel diagnostics that can rapidly target resistant organisms from these bacterial species.
In this study, we developed and evaluated a Direct Mass Spectrometry assay for Beta-Lactamase (D-MSBL) that allows direct identification of (oxyimino)cephalosporin-resistant Escherichia coli or Klebsiella pneumoniae from positive blood cultures (BCs), by using the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology.
The D-MSBL assay was performed on 93 E. coli or K. pneumoniae growing BC samples that were shortly co-incubated with cefotaxime (CTX) as the indicator cephalosporin. Susceptibility and resistance defining peaks from the samples' mass spectra were analyzed by a novel algorithm for bacterial organism classification. The D-MSBL assay allowed discrimination between E. coli and K. pneumoniae that were resistant or susceptible to CTX with a sensitivity of 86.8% and a specificity of 98.2%.
The proposed algorithm-based D-MSBL assay, if integrated in the routine laboratory diagnostic workflow, may be useful to enhance the establishment of appropriate antibiotic therapy and to control the threat of oxyimino-cephalosporin resistance in hospital.
如今，肠杆菌科细菌对氧亚氨基头孢菌素的耐药性在全球范围内传播，这意味着需要能够快速靶向这些细菌物种中耐药菌的新型诊断方法。
在本研究中，我们开发并评估了一种用于β-内酰胺酶的直接质谱分析法（D-MSBL），该方法通过使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）技术，能够从阳性血培养物（BCs）中直接鉴定出对（氧亚氨基）头孢菌素耐药的大肠杆菌或肺炎克雷伯菌。
对93份大肠杆菌或肺炎克雷伯菌生长的血培养样本进行了D-MSBL分析，这些样本与头孢噻肟（CTX）作为指示头孢菌素进行了短期共孵育。通过一种用于细菌分类的新算法分析样本质谱中的药敏和耐药定义峰。D-MSBL分析能够区分对CTX耐药或敏感的大肠杆菌和肺炎克雷伯菌，灵敏度为86.8%，特异性为98.2%。
所提出的基于算法的D-MSBL分析，如果整合到常规实验室诊断工作流程中，可能有助于加强适当抗生素治疗的确定，并控制医院中氧亚氨基头孢菌素耐药性的威胁。
