Steensels Deborah, Deplano Ariane, Denis Olivier, Simon Anne, Verroken Alexia
a Laboratoire de microbiologie , Cliniques universitaires Saint-Luc - Université catholique de Louvain , Brussels , Belgium.
b Department of Clinical Microbiology, National Reference Center S. aureus , ULB Erasme University Hospital , Brussels , Belgium.
Acta Clin Belg. 2017 Aug;72(4):219-225. doi: 10.1080/17843286.2016.1198521. Epub 2016 Jun 24.
The early detection of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak is decisive to control its spread and rapidly initiate adequate infection control measures. Therefore, prompt determination of epidemiologic relatedness of clinical MRSA isolates is essential. Genetic typing methods have a high discriminatory power but their availability remains restricted. In this study, we aimed to challenge matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a typing tool of a nosocomial MRSA outbreak in a neonatal intensive care unit.
Over a 2-year period, 15 MRSA isolates were recovered from patients (n = 14) and health care workers (n = 1) at the neonatal intensive care unit. Five reference strains were included for comparison. Identification was performed by MALDI-TOF MS and susceptibility profiles determined by automated broth microdilution. Typing analysis by MALDI-TOF MS included mean spectrum profiles and subsequent dendrogram creation using BioNumerics software. Results were compared with spa typing and pulsed-field gel electrophoresis (PFGE).
Our study showed good concordance (93%) between PFGE, spa typing, and MALDI-TOF MS for the outbreak-related MRSA strains. MALDI-TOF MS typing showed excellent typeability and discriminatory power but showed poor reproducibility.
This study is one of the first to document the potential usefulness of MALDI-TOF MS with standardized data analysis as a typing tool for investigating a nosocomial MRSA outbreak. A concordance of 93% compared to reference typing techniques was observed. However, because of poor reproducibility, long-term follow-up of prospective isolated strains is not practical for routine use. Further studies are needed to confirm our observations.
耐甲氧西林金黄色葡萄球菌（MRSA）暴发的早期检测对于控制其传播并迅速启动适当的感染控制措施至关重要。因此，迅速确定临床MRSA分离株的流行病学关联性至关重要。基因分型方法具有较高的鉴别力，但其应用仍受到限制。在本研究中，我们旨在挑战基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）作为新生儿重症监护病房医院内MRSA暴发的分型工具。
在两年期间，从新生儿重症监护病房的患者（n = 14）和医护人员（n = 1）中分离出15株MRSA。纳入5株参考菌株进行比较。通过MALDI-TOF MS进行鉴定，并通过自动肉汤微量稀释法测定药敏谱。MALDI-TOF MS的分型分析包括平均光谱图谱以及随后使用BioNumerics软件创建树状图。将结果与spa分型和脉冲场凝胶电泳（PFGE）进行比较。
我们的研究表明，PFGE、spa分型和MALDI-TOF MS对与暴发相关的MRSA菌株的一致性良好（93%）。MALDI-TOF MS分型显示出出色的分型能力和鉴别力，但再现性较差。
本研究是最早记录MALDI-TOF MS结合标准化数据分析作为调查医院内MRSA暴发的分型工具的潜在实用性的研究之一。与参考分型技术相比，观察到一致性为93%。然而，由于再现性较差，对前瞻性分离菌株进行长期随访不适合常规使用。需要进一步研究来证实我们的观察结果。
