Pitell Sarah, Woo Cheolwoon, Millstone Jill, Stout Janet, Gilbertson Leanne, Haig Sarah-Jane
Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA, United States.
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States.
Front Public Health. 2025 May 26;13:1572869. doi: 10.3389/fpubh.2025.1572869. eCollection 2025.
Antimicrobial silver materials for drinking water disinfection have become increasingly popular in building-wide systems (e.g., copper-silver ionization) and point-of-use applications (e.g., silver containing plumbing fixtures) to combat the microbial growth of drinking water associated pathogens that can cause infections in the immunocompromised (DWPIs). However, evaluations of various silver-containing treatments suggest that their efficacy is often temporary or incomplete. A potential explanation of these observations is insufficient dosing of silver into the drinking water to reduce these types of microorganisms, which are known to be more resistant to biocides. Instead, sublethal exposure may cause these microorganisms to adapt in ways that increase their resistance to disinfection. In this study, we assessed the effects of different silver concentrations on biofilms of clinically and environmentally isolated , a biofilm-forming member of the drinking water microbiota with public health and environmental significance, in a bench-scale system operated to simulated the use patterns of antimicrobial showerheads. We found that high concentrations of silver significantly reduced biofilms cell densities and impacted cellular aggregation behavior, but ultimately made the resulting treated water non-potable due to the concentration of silver needed to solicit these effects. Silver concentrations that were more appropriate for drinking water applications resulting in limited reduction in viable . Additionally, transcriptomic analysis revealed that genes related to stress survival were upregulated in all experimental conditions: genes related to flavoprotein, chaperone, and protease synthesis, ribosome synthesis, and cysteine and methionine metabolism were upregulated in the lower dose condition, and peptidoglycan synthesis and antioxidant production were upregulated in the higher silver dose condition. These expressional changes may enhance survival and pathogenicity traits in after silver exposure. Overall, our findings indicate that silver exposure drives meaningful changes in biofilm behavior and gene expression in isolates, yet does not inactivate under the simulated conditions.
用于饮用水消毒的抗菌银材料在建筑范围内的系统（如铜银离子化）和使用点应用（如含银管道装置）中越来越受欢迎，以对抗与饮用水相关的病原体的微生物生长，这些病原体可导致免疫功能低下者感染（DWPI）。然而，对各种含银处理方法的评估表明，它们的功效往往是暂时的或不完全的。对这些观察结果的一个潜在解释是，向饮用水中添加的银剂量不足，无法减少这类已知对杀菌剂更具抗性的微生物。相反，亚致死暴露可能会使这些微生物以增加其对消毒抗性的方式适应。在本研究中，我们在一个模拟抗菌淋浴喷头使用模式的实验室规模系统中，评估了不同银浓度对临床和环境分离的嗜麦芽窄食单胞菌生物膜的影响，嗜麦芽窄食单胞菌是具有公共卫生和环境意义的饮用水微生物群中的一种生物膜形成成员。我们发现，高浓度的银显著降低了生物膜细胞密度并影响了细胞聚集行为，但由于产生这些效果所需的银浓度，最终使处理后的水无法饮用。更适合饮用水应用的银浓度导致活菌数量减少有限。此外，转录组分析显示，在所有实验条件下，与应激存活相关的基因均上调：在低剂量条件下，与黄素蛋白、伴侣蛋白和蛋白酶合成、核糖体合成以及半胱氨酸和甲硫氨酸代谢相关的基因上调，而在高银剂量条件下，肽聚糖合成和抗氧化剂产生上调。这些表达变化可能会增强嗜麦芽窄食单胞菌在银暴露后的存活和致病特性。总体而言，我们的研究结果表明，银暴露会驱动嗜麦芽窄食单胞菌分离株生物膜行为和基因表达发生有意义的变化，但在模拟条件下不会使嗜麦芽窄食单胞菌失活。
