背景介绍

呼吸机相关性肺炎(VAP)是医院特护病房最常见的院内感染,即便当下的患者护理技术更加完善、气管导管设计更加成熟,仍然难以避免这一问题。气管导管为细菌进入下呼吸道提供了通道,同时也为细菌生物被膜形成提供了温床,这两者都会导致呼吸机相关性肺炎。一种创新的微观有序表面结构,Sharklet微结构已经证实能够有效减少多种微生物附着,运用在气管导管表面或许能够成为有效减少呼吸机相关性肺炎的另一种策略。为了评估这一微结构的应用可行性,除了在进行有黏蛋白介导下和无黏蛋白介导下的细菌生物被膜形成研究之外,还开展了微生物层面的研究以模拟体外气管环境。

Methods

The top five pathogens associated with ETT-related pneumonia, Methicillin-Resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Klebsiella pneumonia, Acinetobacter baumannii, and Escherichia coli, were evaluated for attachment to micro-patterned and un-patterned silicone surfaces in a short-term colonization assay. Two key pathogens, MRSA and Pseudomonas aeruginosa, were evaluated for biofilm formation in a nutrient rich broth for four days and minimal media for 24 hours, respectively, on each surface type. P. aeruginosa was further evaluated for biofilm formation on each surface type in a mucin-modified medium mimicking tracheal mucosal secretions. Results are reported as percent reductions and significance is based on t-tests and ANOVA models of log reductions. All experiments were replicated at least three times.

Results

Micro-patterned surfaces demonstrated reductions in microbial colonization for a broad range of species, with up to 99.9% (p < 0.05) reduction compared to un-patterned controls. Biofilm formation was also reduced, with 67% (p = 0.12) and 52% (p = 0.05) reductions in MRSA and P. aeruginosa biofilm formation, respectively. Further, a 58% (p < 0.01) reduction was demonstrated on micro-patterned surfaces for P. aeruginosa biofilms under clinically-simulated conditions when compared to un-patterned controls.

Conclusions

This engineered micro-pattern reduces the colonization and biofilm formation of key VAP-associated pathogens in vitro. Future application of this micro-pattern on endotracheal tubes may prevent or prolong the onset of VAP without the need for antimicrobial agents.

 

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