Identification of vancomycin-resistant Enterococcus faecium by MALDI-TOF MS and epidemiological typing performance

doi:10.3969/j.issn.1673-8640.2020.05.017

Abstract

Abstract:

Objective To identify vanA-positive vancomycin-resistant Enterococcus faecium（VREfm） and vancomycin-susceptible Enterococcus faecium（VSEfm） and determine the epidemiological correlation of VREfm by matrix-assisted laser desorption ionization-time of flight mass spectrometry（MALDI-TOF MS）. Methods A total of 139 Enterococcus faecium isolates were collected,and there were 66 VREfm and 73 VSEfm. Vancomycin resistance genes of 66 VREfm were confirmed by polymerase chain reaction（PCR）. Enterococcus faecium isolates were identified by MALDI-TOF MS. Models with ClinProTools 3.0 software were generated using the spectra of 45 VREfm and 50 VSEfm randomly selected. The remaining 21 VREfm and 23 VSEfm were validated with optimal model. Totally,21 VREfm randomly selected were analyzed by multilocus sequence typing（MLST） and subjected to hierarchical cluster analysis by MALDI-TOF MS. Results A total of 139 Enterococcus faeciumisolates were identified by MALDI-TOF MS,and the score range was 2.321-2.602. All the 66 VREfm carried vanA gene. External validation of the optimal model generated produced a sensitivity of 95.2% and a specificity of 95.7%. There were 7 sequence types（ST） of 21 VREfm,with most isolates identified as ST78. Hierarchical cluster analysis showed that 21 VREfm were classified into 4 clusters. Most of the ST78 isolates were classified into the same cluster,and highly-ST78-related ST were also classified into the ST78 cluster. Conclusions MALDI-TOF MS can rapidly differentiate vanA-positive VREfm from VSEfm with strict control of experimental conditions. Highly-related ST of VREfm are distinguishable.

Key words: Matrix-assisted laser desorption ionization-time of flight mass spectrometry, Vancomycin-resistant Enterococcus faecium, Vancomycin-susceptible Enterococcus faecium, Multilocus sequence typing

CLC Number:

R446.1

WU Siying, WANG Xiaoqing, LIU Shanquan, XIAO Yuling, HE Chao, MA Ying, XIE Yi, KANG Mei. Identification of vancomycin-resistant Enterococcus faecium by MALDI-TOF MS and epidemiological typing performance[J]. Laboratory Medicine, 2020, 35(5): 470-475.

Figures/Tables 4

References 17

[1]	BRILLIANTOVA A N,KLIASOVA G A,MIRONOVA A V,et al.Spread of vancomycin-resistant Enterococcus faecium in two haematological centres in Russia[J]. Int J Antimicrob Agents,2010,35(2):177-181.
[2]	THIERFELDER C,KELLER P M,KOCHER C,et al.Vancomycin-resistant Enterococcus[J]. Swiss Med Wkly,2012,142:w13540.
[3]	GRIFFIN P M,PRICE G R,SCHOONEVELDT J M,et al.Use of matrix-assisted laser desorption ionization-time of flight mass spectrometry to identify vancomycin-resistant enterococci and investigate the epidemiology of an outbreak[J]. J Clin Microbiol,2012,50(9):2918-2931.
[4]	ANANTHARAJAH A,TOSSENS B,OLIVE N,et al.Performance evaluation of the MBT STAR®-Carba IVD assay for the detection of carbapenemases with MALDI-TOF MS[J]. Front Microbiol,2019,10:1413.
[5]	LIN J,XU C,FANG R,et al.Resistance and heteroresistance to colistin in Pseudomonas aeruginosa isolates from Wenzhou,China[J]. Antimicrob Agents Chemother,2019,63(10):e00556-19.
[6]	NEONAKIS I K,SPANDIDOS D A.Detection of carbapenemase producers by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry(MALDI-TOF MS)[J]. Eur J Clin Microbiol Infect Dis,2019,38(10):1795-1801.
[7]	VANKERCKHOVEN V,VAN AUTGAERDEN T,VAEL C,et al.Development of a multiplex PCR for the detection of asa1,gelE,cylA,esp,and hyl genes in Enterococci and survey for virulence determinants among European hospital isolates of Enterococcus faecium[J]. J Clin Microbiol,2004,42(10):4473-4479.
[8]	吴薇,王利君,隋文君,等. 基质辅助激光解析电离飞行时间质谱技术早期筛查耐万古霉素屎肠球菌[J]. 首都医科大学学报,2015,36(3):444-448.
[9]	CONWAY G C,SMOLE S C,SARRACINO D A,et al.Phyloproteomics:species identification of Enterobacteriaceae using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry[J]. J Mol Microbiol Biotechnol,2001,3(1):103-112.
[10]	DU Z,YANG R,GUO Z,et al.Identification of Staphylococcus aureus and determination of its methicillin resistance by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry[J]. Anal Chem,2002,74(21):5487-5491.
[11]	SMOLE S C,KING L A,LEOPOLD P E,et al.Sample preparation of Gram-positive bacteria for identification by matrix assisted laser desorption/ionization time-of-flight[J]. J Microbiol Methods,2002,48(2-3):107-115.
[12]	陆文香,张媛,王莹超,等. 基质辅助激光解析电离飞行时间质谱技术快速鉴定耐万古霉素屎肠球菌[J]. 江苏大学学报(医学版),2017,27(6):474-477.
[13]	MENG X,YANG J,DUAN J,et al.Assessing molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae(CR-KP) with MLST and MALDI-TOF in central China[J]. Sci Rep,2019,9(1):2271.
[14]	RÖDEL J,MELLMANN A,STEIN C,et al. Use of MALDI-TOF mass spectrometry to detect nosocomial outbreaks of Serratia marcescens and Citrobacter freundii[J]. Eur J Clin Microbiol Infect Dis,2019,38(3):581-591.
[15]	LASCH P,FLEIGE C,STÄMMLER M,et al. Insufficient discriminatory power of MALDI-TOF mass spectrometry for typing of Enterococcus faecium and Staphylococcus aureus isolates[J]. J Microbiol Methods,2014,100:58-69.
[16]	SCHLEBUSCH S,PRICE G R,GALLAGHER R L,et al.MALDI-TOF MS meets WGS in a VRE outbreak investigation[J]. Eur J Clin Microbiol Infect Dis,2017,36(3):495-499.
[17]	FREITAS A R,SOUSA C,NOVAIS C,et al.Rapid detection of high-risk Enterococcus faecium clones by matrix-assisted laser desorption ionization time-of-flight mass spectrometry[J]. Diagn Microbiol Infect Dis,2017,87(4):299-307.

质谱峰	质荷比/ （m/z）	DAVE	PTTA	PWKW	PAD	Ave1	Ave2	StdDev1	StdDev2	VREfm组变异系数/%	VSEfm组变异系数/%
97	6 699.6	2.78	<0.000 001	<0.000 001	0.000 003 87	2.52	5.30	0.73	1.83	29.04	34.48
20	2 428.17	4.63	<0.000 001	<0.000 001	<0.000 001	6.91	2.27	3.19	1.25	46.12	54.89
117	8 119.98	1.4	<0.000 001	<0.000 001	0.000 441	1.97	3.37	0.54	0.98	27.48	28.94
135	10 225.33	3.05	<0.000 001	<0.000 001	0.000 001 83	2.04	5.09	0.85	2.30	41.48	45.10
85	6 341.92	7.48	<0.000 001	<0.000 001	0.007 05	9.66	17.14	2.68	5.67	27.74	33.08

质谱峰	质荷比/ （m/z）	DAVE	PTTA	PWKW	PAD	Ave1	Ave2	StdDev1	StdDev2	VREfm组变异系数/%	VSEfm组变异系数/%
97	6 699.6	2.78	<0.000 001	<0.000 001	0.000 003 87	2.52	5.30	0.73	1.83	29.04	34.48
20	2 428.17	4.63	<0.000 001	<0.000 001	<0.000 001	6.91	2.27	3.19	1.25	46.12	54.89
117	8 119.98	1.4	<0.000 001	<0.000 001	0.000 441	1.97	3.37	0.54	0.98	27.48	28.94
135	10 225.33	3.05	<0.000 001	<0.000 001	0.000 001 83	2.04	5.09	0.85	2.30	41.48	45.10
85	6 341.92	7.48	<0.000 001	<0.000 001	0.007 05	9.66	17.14	2.68	5.67	27.74	33.08