Department of Bacteriology, Hygiene and Environment Laboratory, CHU Martinique, CS 90632, Fort-de-France, Cedex, Martinique.
Department of Clinical Research and Innovation, CHU Martinique, CS 90632, Fort-de-France, Cedex, Martinique.
Microbiologyopen. 2023 Feb;12(1):e1330. doi: 10.1002/mbo3.1330.
The inanimate environment immediately surrounding the patient in healthcare facilities is a reservoir of microorganisms embedded in dry-surface biofilms (DSB). These biofilms, first highlighted in 2012, are increasingly studied, but currently available in-vitro models only allow for the growth of semi-hydrated biofilms. We developed a new in-vitro method under actual dehydration conditions based on the hypothesis that surface contamination is mainly due to splashes of respiratory secretions. The main objective of this study was to show that the operating conditions we have defined allowed the growth of DSB with a methicillin resistant Staphylococcus aureus strain. The second objective was to show that extended-spectrum beta-lactamase-producing Enterobacteriaceae, that is, Klebsiella pneumoniae and Enterobacter cloacae were also able to grow such biofilms under these conditions. Monobacterial suspensions in sterile artificial saliva (SAS) were sprayed onto polyethylene surfaces. Nutrients and hydration were provided daily by spraying SAS enriched with 20% of Brain Heart Infusion broth. The primary outcome was mean surface coverage measured by image analysis after crystal violet staining. The method applied to S. aureus for 12 days resulted in reproducible and repeatable DSB consisting of isolated and confluent microcolonies embedded in extracellular polymeric substances as shown in scanning electron microscopy images. Similar DSB were obtained with both Enterobacteriaceae applying the same method. No interspecies variation was shown between the three strains in terms of surface coverage. These first trials are the starting point for a 3-year study currently in process.
医疗机构中紧邻患者的无生命环境是微生物的储存库，这些微生物嵌入在干燥表面生物膜（DSB）中。这些生物膜于 2012 年首次被强调，目前越来越受到研究关注，但现有的体外模型只能允许半水合生物膜的生长。我们根据表面污染主要是由于呼吸道分泌物飞溅的假设，在实际脱水条件下开发了一种新的体外方法。本研究的主要目的是表明我们定义的操作条件允许耐甲氧西林金黄色葡萄球菌（MRSA）菌株生长 DSB。第二个目标是表明产超广谱β-内酰胺酶的肠杆菌科，即肺炎克雷伯菌和阴沟肠杆菌，也能够在这些条件下生长这种生物膜。将无菌人工唾液（SAS）中的单菌悬浮液喷洒到聚乙烯表面。每天通过喷洒含有 20%脑心浸液肉汤的 SAS 来提供营养和水分。主要结果是通过结晶紫染色后的图像分析测量的平均表面覆盖率。该方法应用于金黄色葡萄球菌 12 天，得到了可重复的 DSB，由嵌入细胞外聚合物中的孤立和融合微菌落组成，如扫描电子显微镜图像所示。用相同的方法对两种肠杆菌科也获得了类似的 DSB。在表面覆盖率方面，三种菌株之间没有显示出种间差异。这些初步试验是目前正在进行的为期 3 年研究的起点。
