Biofilm Formation on Endotracheal and Tracheostomy Tubing: A Systematic Review and Meta-Analysis of Culture Data and Sampling Method

Abstract

Biofilm formation on tracheal tubing is a key risk factor for ventilator-associated pneumonia. Endotracheal tube microbiology has been systematically reviewed, but tracheostomy tube profiles have not. Analysis of the tube-associated microbiome is not standardised, and sampling methods are varied. We compared the reported microbiomes of endotracheal and tracheostomy tubes and examined the impact of sampling by tracheal aspiration or direct culture. We searched PubMed, SCOPUS, and Web of Knowledge for clinical microbiology studies from 2000-2024, extracting tubing type, sampling method, and the most prevalent genera identified. Genera were compared by Spearman's rank correlation and pairwise analyses by Šidák's test. Extraction from 49 studies identified 30 genera. Pseudomonas was the most prevalent in all conditions followed by Klebsiella, Staphylococcus, and Acinetobacter. 25 studies performed tracheal aspiration, and 22, direct culture. Two studies used both methods. Correlation was observed between endotracheal and tracheostomy tubes, and aspirates and direct cultures (Spearman's rho = 0.69; 0.59). Pseudomonas were more prevalent in tracheostomy tubes (p < 0.0001). Coagulase-positive Staphylococci were more common in tracheal aspirates, and coagulase-negative Staphylococci in direct culture. The microbial profiles of endotracheal and tracheostomy tubes are comparable, with Pseudomonas being the most common coloniser. Our analyses suggest that tracheal aspiration can effectively identify the constituents of biofilms without requiring tube removal, making it a valuable tool for clinical researchers to analyse or monitor biofilms before extubation or device failure using existing microbiology procedures.

Keywords: Pseudomonas; biofilm; microbiome; respiratory infections.

Figure 1

PRIMA flow of study selection process.

Figure 2

Prevalence of genera in endotracheal and tracheostomy tubing when sampled by tracheal aspiration or direct culture. Proportions of most prevalent isolates identified by all sampling methods from (upper‐left) endotracheal tubes or (upper‐right) tracheostomy tubes. Summary of most prevalent isolates identified on both tracheostomy and endotracheal tubes samples by (lower‐left) tracheal aspiration or (lower‐right) direct culture. A breakdown of prevalence of “Other Genera” is available in the supplementary material (CoPS: Coagulase positive Staphylococcus, “CoNS”: Coagulase negative Staphylococcus).

Figure 3

Meta‐analysis of extracted data. Genera were ranked by prevalence within each study and then scored based on their mean rank. Spearman's rank correlation of (a) endotracheal vs tracheostomy tubes, (Spearman's rho = 0.61, p < 0.0001) and (b) aspirate vs direct samples (Spearman's rho = 0.59, p < 0.001). Pairwise comparisons of mean score of (c) endotracheal vs tracheostomy tubes, and (d) aspirate vs direct samples. “CoPS”: Coagulase positive Staphylococcus, “CoNS”: Coagulase negative Staphylococcus (Statistical significance calculated by way of Šidák's multiple comparisons test ****p < 0.0001, **p < 0.01).