Antimicrobial Solutions for Endotracheal Tubes in Prevention of Ventilator-Associated Pneumonia

Abstract

Ventilator-associated pneumonia is one of the most frequently encountered hospital infections and is an essential issue in the healthcare field. It is usually linked to a high mortality rate and prolonged hospitalization time. There is a lack of treatment, so alternative solutions must be continuously sought. The endotracheal tube is an indwelling device that is a significant culprit for ventilator-associated pneumonia because its surface can be colonized by different types of pathogens, which generate a multispecies biofilm. In the paper, we discuss the definition of ventilator-associated pneumonia, the economic burdens, and its outcomes. Then, we present the latest technological solutions for endotracheal tube surfaces, such as active antimicrobial coatings, passive coatings, and combinatorial methods, with examples from the literature. We end our analysis by identifying the gaps existing in the present research and investigating future possibilities that can decrease ventilator-associated pneumonia cases and improve patient comfort during treatment.

Keywords: antimicrobial coating; biofilm; endotracheal tube; ventilator-associated pneumonia.

Figure 1

Ventilator-associated pneumonia development based on biofilm formation on the endotracheal tube surface. Adapted from [19] (CC-BY 3.0 in the original reference).

Figure 2

Stages of complex biofilm formation on ETT surface: (a) attachment phase, in which bacteria change their state from planktonic to sessile; (b) establishment phase characterized by secretion of biofilm extracellular matrix; (c) development and maturement of the biofilm; (d) biofilm dispersion and disassembly.

Figure 3

Architecture of a standard ETT.

Figure 4

SEM images of biofilm formation: (a) P. aeruginosa and (b) S. aureus in the case of uncoated and polyamide/AgNP composite-coated ETTs at times between 24 h and 72 h (magnification 5000×) [85]. Reprinted from [85]. Copyright (2023), with permission from Taylor & Francis.

Figure 5

Oral mucous irritation tests in the golden hamster animal model for the bare and Ag-SiO₂-modified polyethylene ETTs [88]. Figure is licensed under CC-BY 4.0.

Figure 6

Antimicrobial efficiency of silver-, gardine-, and gendine-coated ETTs. The in vitro adherence of MRSA (Methicillin-resistant S. aureus), PS (P. aeruginosa), and An (A. baumannii) was studied. After one day, the biofilm cells were dispersed by sonication in neutralizing and non-neutralizing solutions: (A) neutralizing solutions: p = 0.005 uncoated ETT vs. silver-coated ETT, p = 0.003 uncoated ETT vs. gardine-coated ETT (for An p = 0.01), p = 0.003 uncoated ETT vs. gendine-coated ETT, p < 0.003 for silver-coated ETT vs. gendine-coated ETT (for An p = 0.01); (B) non-neutralizing solutions: p < 0.01 uncoated ETT vs. silver-coated ETT, p = 0.003 uncoated ETT vs. gardine-coated ETT (for MRSA p = 0.004), p = 0.003 silver-coated ETT vs. gardine-coated ETT (for An p = 0.18) [100]. Reprinted from [100] Copyright (2023), with permission from Elsevier.

Figure 7

AFM images of topography for control (A) and nano-rough surface PVC (B), control (C,E) and nano-rough surface PVC (D,F) soaked in 10 mM and 100 mM [121]. Figure is licensed under CC-BY NC 3.0.

Figure 8

SEM images of PVC samples: (A) unmodified PVC; ethanol/methanol-modified PVC (B,F) 15% (v/v); (C,G) 20% (v/v); (D,H) 25% (v/v); (E,I) 35% (v/v). Inserts indicate the CA for each surface, and the bar represents 10 μm [126]. Reprinted from [126]. Copyright (2023), with permission from Elsevier.

Figure 9

The micropatterned surface efficiency was tested against MRSA and P. aeruginosa in comparison with unpatterned ETT. MRSA and PA14ΔbifA strains were characterized by 67% (p = 0.123) and 52% (p = 0.05) median reduction in biofilm compared with the control sample. In the case of P. aeruginosa (ATCC 9027) strain, robust biofilm formation was not observed [128]. Figure is licensed under CC-BY 2.0.