Biofilm Formation in a Permanent Tracheal Stent Implanted for Twenty-Five Years

High microbiome variability in pediatric tracheostomy cannulas in patients with similar clinical characteristics

OBJECTIVES

To evaluate the bacterial microbiome found in tracheostomy cannulas of a group of children diagnosed with glossoptosis secondary to Robin Sequence (RS), and its clinical implications.

METHODS

Pediatric patients were enrolled in the study at the time of the cannula change in the hospital. During this procedure, the removed cannula was collected and stored for amplicon sequencing of 16s rRNA. DNA extraction was performed using DNeasy PowerBiofilm Kit (QIAGEN® ‒ Cat nº 24000-50) while sequencing was performed with the S5 (Ion S5™ System, Thermo Fisher Scientific), following Brazilian Microbiome Project (BMP) protocol.

RESULTS

All 12 patients included in the study were using tracheostomy uncuffed cannulas of the same brand, had tracheostomy performed for over 1-year and had used the removed cannula for approximately 3-months. Most abundant genera found were Aggregatibacter, Pseudomonas, Haemophilus, Neisseria, Staphylococcus, Fusobacterium, Moraxella, Streptococcus, Alloiococcus, and Capnocytophaga. Individual microbiome of each individual was highly variable, not correlating to any particular clinical characteristic.

CONCLUSION

The microbiome of tracheostomy cannulas is highly variable, even among patients with similar clinical characteristics, making it challenging to determine a standard for normality.

Patterned Drug-Eluting Coatings for Tracheal Stents Based on PLA, PLGA, and PCL for the Granulation Formation Reduction: In Vivo Studies

Expandable metallic stent placement is often the only way to treat airway obstructions. Such treatment with an uncoated stent causes granulation proliferation and subsequent restenosis, resulting in the procedure’s adverse complications. Systemic administration of steroids drugs in high dosages slows down granulation tissue overgrowth but leads to long-term side effects. Drug-eluting coatings have been used widely in cardiology for many years to suppress local granulation and reduce the organism’s systemic load. Still, so far, there are no available analogs for the trachea. Here, we demonstrate that PLA-, PCL- and PLGA-based films with arrays of microchambers to accommodate therapeutic substances can be used as a drug-eluting coating through securely fixing on the surface of an expandable nitinol stent. PCL and PLA were most resistant to mechanical damage associated with packing in delivery devices and making it possible to keep high-molecular-weight cargo. Low-molecular-weight methylprednisolone sodium succinate is poorly retained in PCL- and PLGA-based microchambers after immersion in deionized water (only 9.5% and 15.7% are left, respectively). In comparison, PLA-based microchambers retain 96.3% after the same procedure. In vivo studies on rabbits have shown that effective granulation tissue suppression is achieved when PLA and PLGA are used for coatings. PLGA-based microchamber coating almost completely degrades in 10 days in the trachea, while PLA-based microchamber films partially preserve their structure. The PCL-based film coating is most stable over time, which probably causes blocking the outflow of fluid from the tracheal mucosa and the aggravation of the inflammatory process against the background of low drug concentration. Combination and variability of polymers in the fabrication of films with microchambers to retain therapeutic compounds are suggested as a novel type of drug-eluting coating.