School of Health Sciences, University of Southampton, Southampton, United Kingdom
School of Biological Sciences, University of Southampton, Southampton, United Kingdom.
mBio. 2021 Mar 23;12(2):e03584-20. doi: 10.1128/mBio.03584-20.
Catheter-associated urinary tract infections have serious consequences, for both patients and health care resources. Much work has been carried out to develop an antimicrobial catheter. Although such developments have shown promise under laboratory conditions, none have demonstrated a clear advantage in clinical trials. Using a range of microbiological and advanced microscopy techniques, a detailed laboratory study comparing biofilm development on silicone, hydrogel latex, and silver alloy-coated hydrogel latex catheters was carried out. Biofilm development by , , and on three commercially available catheters was tracked over time. Samples were examined with episcopic differential interference contrast (EDIC) microscopy, culture analysis, and staining techniques to quantify viable but nonculturable (VBNC) bacteria. Both qualitative and quantitative assessments found biofilms to develop rapidly on all three materials. EDIC microscopy revealed the rough surface topography of the materials. Differences between culture counts and quantification of total and dead cells demonstrated the presence of VBNC populations, where bacteria retain viability but are not metabolically active. The use of nonculture-based techniques showed the development of widespread VBNC populations. These VBNC populations were more evident on silver alloy-coated hydrogel latex catheters, indicating a bacteriostatic effect at best. The laboratory tests reported here, which detect VBNC bacteria, allow more rigorous assessment of antimicrobial catheters, explaining why there is often minimal benefit to patients. Several antimicrobial urinary catheter materials have been developed, but, although laboratory studies may show a benefit, none have significantly improved clinical outcomes. The use of poorly designed laboratory testing and lack of consideration of the impact of VBNC populations may be responsible. While the presence of VBNC populations is becoming more widely reported, there remains a lack of understanding of the clinical impact or influence of exposure to antimicrobial products. This is the first study to investigate the impact of antimicrobial surface materials and the appearance of VBNC populations. This demonstrates how improved testing is needed before clinical trials are initiated.
导管相关尿路感染会对患者和医疗资源造成严重后果。为了开发抗菌导管，已经开展了大量工作。尽管这些研究在实验室条件下显示出了一定的前景，但在临床试验中没有一项研究显示出明显的优势。本研究使用一系列微生物学和先进显微镜技术，对硅胶、水凝胶乳胶和银合金涂层水凝胶乳胶导管上生物膜形成进行了详细的实验室比较研究。通过时间追踪，研究了 在三种市售导管上的生物膜形成情况。使用相差微分干涉对比（EDIC）显微镜、培养分析和染色技术对样本进行检查，以量化活但非可培养（VBNC）细菌。定性和定量评估都发现生物膜在所有三种材料上都迅速形成。EDIC 显微镜揭示了材料粗糙的表面形貌。培养计数和总细胞及死亡细胞定量之间的差异表明存在 VBNC 群体，这些细菌仍具有活力但无代谢活性。非培养技术的使用显示出广泛的 VBNC 群体的发展。在银合金涂层水凝胶乳胶导管上，VBNC 群体更为明显，这表明最好是具有抑菌作用。这里报告的实验室测试可以检测 VBNC 细菌，从而更严格地评估抗菌导管，这解释了为什么对患者的益处通常很小。已经开发了几种抗菌导尿管材料，但尽管实验室研究可能显示出益处，但没有一种显著改善了临床结果。使用设计不佳的实验室测试且没有考虑 VBNC 群体的影响可能是原因之一。虽然 VBNC 群体的存在报告越来越多，但对其临床影响或接触抗菌产品的影响仍缺乏了解。这是第一项研究抗菌表面材料和 VBNC 群体出现的影响的研究。这表明在启动临床试验之前，需要进行改进的测试。
