Online water bioburden analyzers (OWBAs) can provide real-time feedback on viable bacteria in high-purity water (HPW) systems for pharmaceutical manufacturers. To calibrate and validate OWBAs, which detect bacteria using scattered light and bacterial autofluorescence, standards are needed that mimic the characteristics of bacteria in HPW. To guide selection of potential standards, e.g., fluorescent microspheres, a relevant bacterial contaminant, Ralstonia pickettii, was characterized for size, count, viability, and autofluorescence after exposure for 24 h to HPW or a nutrient environment. The cells exposed to HPW showed smaller sizes, with lower counts and autofluorescence intensities, but similar spectral features. The cell characteristics are discussed in comparison with a set of fluorescent microspheres, considering factors relevant to OWBAs. These studies suggest that fluorescent microspheres should be relatively small (< 1 µm diameter) and dim, while covering a broad emission range from ≈ (420 to 600) nm to best mimic the representative R. pickettii.

中文翻译：

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评估高纯水中皮氏罗尔斯通氏菌的变化，以指导在线水生物负载分析仪潜在校准材料的选择。

在线水生物负载分析仪 (OWBA) 可以为制药商提供高纯水 (HPW) 系统中活细菌的实时反馈。为了校准和验证使用散射光和细菌自发荧光检测细菌的 OWBA，需要模拟 HPW 中细菌特征的标准。为了指导潜在标准品（例如荧光微球）的选择，对相关细菌污染物（Ralstonia pickettii）暴露于 HPW 或营养环境 24 小时后的大小、计数、活力和自发荧光进行了表征。暴露于 HPW 的细胞尺寸较小，计数和自发荧光强度较低，但光谱特征相似。考虑与 OWBA 相关的因素，通过与一组荧光微球进行比较来讨论细胞特性。这些研究表明，荧光微球应该相对较小（直径 < 1 µm）且暗淡，同时覆盖约（420 至 600）nm 的宽发射范围，以最好地模仿代表性的 R. pickettii。