Microvida, Laboratory of Medical Microbiology and Immunology, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands.
Reinier de Graaf Hospital, Delft, The Netherlands.
Antimicrob Resist Infect Control. 2023 Jan 5;12(1):1. doi: 10.1186/s13756-022-01207-7.
Methicillin resistant Staphylococcus aureus (MRSA) is a major burden for hospitals globally. However, in the Netherlands, the MRSA prevalence is relatively low due to the 'search and destroy' policy. Routine multiple-locus variable-number of tandem repeat analysis (MLVA) of MRSA isolates supports outbreak detection. However, whole genome multiple locus sequence typing (wgMLST) is superior to MLVA in identifying (pseudo-)outbreaks with MRSA. The present study describes a pseudo-outbreak of MRSA at the bacteriology laboratory of a large Dutch teaching hospital.
All staff members of the bacteriology laboratory of the Elisabeth-TweeSteden hospital were screened for MRSA carriage, after a laboratory contamination with MRSA was suspected. Clonal relatedness between the index isolate and the MRSA isolates from laboratory staff members and all previous MRSA isolates from the Elisabeth-TweeSteden hospital with the same MLVA-type as the index case was examined based on wgMLST using whole genome sequencing.
One of the staff members was identified as the probable source of the laboratory contamination, because of carriage of a MRSA possessing the same MLVA-type as the index case. Eleven other isolates with the same molecular characteristics were found in the database, of which seven were retrospectively suspected of contamination. Clonal relatedness was found between ten isolates, including the isolate found in the staff member and the MRSA found in the index patient with a maximum of eleven alleles difference. All isolates were epidemiologically linked through the laboratory staff member, who had worked on all these cultures.
The present study describes a MRSA pseudo-outbreak over a 2.5-year period due to laboratory contamination caused by a MRSA carrying laboratory staff member involving nine patients. In case of unexpected bacteriological findings, the possibility of a laboratory contamination should be considered.
耐甲氧西林金黄色葡萄球菌（MRSA）是全球医院的主要负担。然而，由于采用了“搜索和消灭”策略，荷兰的 MRSA 患病率相对较低。对 MRSA 分离株进行常规多位点可变数目串联重复分析（MLVA）有助于发现暴发。然而，全基因组多位点序列分型（wgMLST）在识别 MRSA 暴发（假暴发）方面优于 MLVA。本研究描述了荷兰一家大型教学医院细菌学实验室发生的 MRSA 假暴发。
在怀疑细菌学实验室受到 MRSA 污染后，对伊丽莎白-特温斯滕医院的所有细菌学实验室工作人员进行了 MRSA 携带筛查。根据 wgMLST 使用全基因组测序，对索引分离株与实验室工作人员的 MRSA 分离株以及伊丽莎白-特温斯滕医院所有以前的 MRSA 分离株之间的克隆相关性进行了研究，这些分离株与索引病例的 MLVA 型相同。
由于携带与索引病例相同 MLVA 型的 MRSA，一名工作人员被确定为实验室污染的可能来源。在数据库中发现了 11 个其他具有相同分子特征的分离株，其中 7 个被怀疑是污染。在包括在工作人员中发现的分离株和在索引患者中发现的 MRSA 在内的 10 个分离株之间发现了克隆相关性，最大等位基因差异为 11 个。所有分离株均通过曾从事所有这些培养物的实验室工作人员在流行病学上联系在一起。
本研究描述了由于携带实验室工作人员的 MRSA 引起的实验室污染导致的 2.5 年期间的 MRSA 假暴发，涉及 9 名患者。在出现意外细菌学发现的情况下，应考虑实验室污染的可能性。
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