MALDI-TOF MS在新生儿血流感染恶臭假单胞菌同源性分析中的应用

Application of MALDI-TOF MS to homology analysis of Pseudomonas putida in neonatal bloodstream infection

目的 探讨基质辅助激光解析电离飞行时间质谱(matrix-assisted laser desorption/ionization time of flight mass spectrometry, MALDI-TOF MS)技术在新生儿血流感染恶臭假单胞菌同源性分析中的应用。方法 收集湖南省儿童医院新生儿病区7株新生儿血流感染恶臭假单胞菌株,利用VITEK-Compact 2检测药敏结果;运用MALDI-TOF MS及SARAMIS软件检测及分析该批恶臭假单胞菌的同源性;同时运用全基因测序(whole genome sequencing, WGS)的方法来验证MALDI-TOF MS分析结果。结果 7株恶臭假单胞菌对头孢三代以上抗生素及碳青酶烯类抗生素均不敏感,对阿米卡星及左氧氟沙星都敏感。通过运用MALDI-TOF MS及SARAMIS软件发现该7株恶臭假单胞菌为同一型的相对相似度在80%-90%之间。WGS分析发现:该7株恶臭假单胞菌多位点序列分型(multilocus sequence typing, MLST)均为128型,平均核苷酸相似度(average nucleotide identity, ANI)>99.9%。结论 本次研究的7株恶臭假单胞菌有相似的耐药表型,MALDI-TOF MS发现他们为同一型的相对相似度在80%-90%之间,WGS验证他们为同一菌株来源;MALDI-TOF MS可以对恶臭假单胞菌进行初步、快速的同源性分析。

Objective To explore the application of matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS) in homology analysis of Pseudomonas putida in neonatal bloodstream infection.Methods Seven strains of Pseudomonas putida in neonatal bloodstream infection were collected from neonatal ward of Hunan Children’s Hospital.VITEK-compact 2 was used to detect drug sensitivity.MALDI-TOF MS and S ARAM IS software were employed to detect and analyze the homology of the Pseudomonas putida strains.Meanwhile,whole genome sequencing(WGS) was applied to verifying the analysis results of MALDI-TOF MS.Results The 7 Pseudomonas putida strains were not sensitive to third-and fourth-generation cephalosporins and carbapenase antibiotics,but sensitive to amikacin and levofloxacin.By using MALDI-TOF MS and SARAMIS software,it was found that the relative similarity in the 7 Pseudomonas putida strains ranged from80% to 90%.WGS analysis revealed that all the 7 Pseudomonas putida strains were MLST-128,with an average nucleotide identity(ANI) being> 99.9%.Conclusion The 7 Pseudomonas putida strains in this study had similar drug resistance phenotypes.MALDI-TOF MS found that they were of the same type with the relative similarity being 80%-90%.WGS confirmed that they were from the same strain.MALDI-TOF MS can be used for preliminary and rapid homology analysis of Pseudomonas putida.