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| apid identification of vancomycin-resistant Enterococcus faecium by MALDI-TOF MS |
| LU Wen-xiang 1, ZHANG Yuan 2,* , WANG Ying-chao 1, GAO Jing-jing 1, XU Wei-dong 1 , ZHU Qin-fang 1 |
| (1. Department of Clinical Laboratory, the Municipal Hospital of Suzhou, Suzhou Jiangsu 215002; 2. Second Clinical Medical College of Soochow University, Suzhou Jiangsu 215004, China) |
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Abstract Objective: To identify vancomycin resistant Enterococcus faecium(VRE) and vancomycin susceptible Enterococcus faecium (VSE) by using the matrixassisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF MS). Methods: The clinically isolated Enterococcus faecium were collected,and the resistance of vancomycin was confirmed by instrumental method and Kirby-Bauer(K-B) method. The strain was identified by MALDI-TOF MS and the map was collected. The mass spectra were analyzed by ClinProTools 3.0 software. The mass spectra of 25 VRE and 50 VSE were randomly selected for the establishment of the model. The remaining 15 VRE and 35 VSE were validated by the established model. Results: The genetic algorithm(GA),fast classification algorithm(QC), supervised neural network algorithm(SNN) were established by ClinProTools 3.0 software. The cross validation and recognition capabilities of the three models were 95.65%/100%,87.62%/94.98%,62.54%/100%. Mass spectral ratios of 2 194.94, 3 022.15,3 167.47 and 4 058.08 m/z were the most significant characteristic peaks for distinguishing VRE and VSE, i.e., differential protein peaks between the two strains(peak 6, peak 27,peak 32, peak 52). The receiver operator characteristic curve showed that the area under curve of these four characteristic peaks was about 0.9. Three types of models were used for external validation: the sensitivity and specificity of the GA,QC,SNN algorithm for the VRE were 86.7%/82.8%,73.3%/85.7%,66.7%/80.0%. Conclusion: MALDI-TOF MS can be used for rapid identification of VRE and VSE with strict control of experimental conditions, which is timesaving, sensitive and specific. ［Key words］MAIDI-TOF MS； Enterococcus faecium； vancomycin； drug resistance
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Received: 01 June 2017
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2017, Vol. 27 
