Department of Surgical, Medical, Dental and Morphological Sciences with interest in Transplant, Oncological and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy.
Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
BMC Microbiol. 2018 Aug 14;18(1):84. doi: 10.1186/s12866-018-1224-6.
Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for both acute and chronic infections in humans. In particular, its ability to form biofilm, on biotic and abiotic surfaces, makes it particularly resistant to host's immune defenses and current antibiotic therapies as well. Innovative antimicrobial materials, like hydrogel, silver salts or nanoparticles have been used to cover new generation catheters with promising results. Nevertheless, biofilm remains a major health problem. For instance, biofilm produced onto endotracheal tubes (ETT) of ventilated patients plays a relevant role in the onset of ventilation-associated pneumonia. Most of our knowledge on Pseudomonas aeruginosa biofilm derives from in vitro studies carried out on abiotic surfaces, such as polystyrene microplates or plastic materials used for ETT manufacturing. However, these approaches often provide underestimated results since other parameters, in addition to bacterial features (i.e. shape and material composition of ETT) might strongly influence biofilm formation.
We used an already established biofilm development assay on medically-relevant foreign devices (CVC catheters) by a stably transformed bioluminescent (BLI)-Pseudomonas aeruginosa strain, in order to follow up biofilm formation on ETT by bioluminescence detection. Our results demonstrated that it is possible: i) to monitor BLI-Pseudomonas aeruginosa biofilm development on ETT pieces in real-time, ii) to evaluate the three-dimensional structure of biofilm directly on ETT, iii) to assess metabolic behavior and the production of microbial virulence traits of bacteria embedded on ETT-biofilm.
Overall, we were able to standardize a rapid and easy-to-perform in vitro model for real-time monitoring Pseudomonas aeruginosa biofilm formation directly onto ETT pieces, taking into account not only microbial factors, but also ETT shape and material. Our study provides a rapid method for future screening and validation of novel antimicrobial drugs as well as for the evaluation of novel biomaterials employed in the production of new classes of ETT.
铜绿假单胞菌是一种机会性病原体细菌，可导致人类急性和慢性感染。特别是，它在生物和非生物表面形成生物膜的能力，使其特别能够抵抗宿主的免疫防御和当前的抗生素治疗。创新的抗菌材料，如水凝胶、银盐或纳米粒子，已被用于覆盖新一代导管，并取得了有希望的结果。然而，生物膜仍然是一个主要的健康问题。例如，在通气患者的气管内导管（ETT）上产生的生物膜在呼吸机相关性肺炎的发病中起着重要作用。我们对铜绿假单胞菌生物膜的大部分了解来自于在非生物表面（如聚苯乙烯微板或用于 ETT 制造的塑料材料）上进行的体外研究。然而，这些方法往往提供了被低估的结果，因为除了细菌特征（即 ETT 的形状和材料组成）之外的其他参数可能强烈影响生物膜的形成。
我们使用一种已经建立的生物膜发展测定法，对有医学意义的外来设备（CVC 导管）进行了稳定转化的生物发光（BLI）-铜绿假单胞菌菌株的生物膜形成，以便通过生物发光检测跟踪 ETT 上的生物膜形成。我们的结果表明，有可能：i）实时监测 ETT 上 BLI-铜绿假单胞菌生物膜的发展，ii）直接在 ETT 上评估生物膜的三维结构，iii）评估嵌入 ETT-生物膜中的细菌的代谢行为和微生物毒力特征的产生。
总的来说，我们能够标准化一种快速且易于执行的体外模型，用于直接在 ETT 上实时监测铜绿假单胞菌生物膜的形成，不仅考虑了微生物因素，还考虑了 ETT 的形状和材料。我们的研究为未来筛选和验证新型抗菌药物以及评估用于生产新型 ETT 类别的新型生物材料提供了一种快速方法。
