Tracheobronchitis in Noncritically Ill Children With Tracheostomy: Can Quantitative Tracheal Cultures Assist in the Management?

Background And Objectives: Bacteria in tracheal aspirate samples from children with tracheostomy can indicate infection or colonization. Our study aimed to determine whether bacterial counts > 10 or > 10 CFU (colony forming units)/mL are more frequently associated with tracheobronchitis. Additionally, we aimed to examine the association between bacterial count and variables distinguishing colonization from infection in tracheobronchitis, along with clinical severity indicators.

Methods: Retrospective cohort study of children with tracheostomy at La Paz University Hospital, Madrid (June 2018-April 2023). Inclusion criteria were tracheal aspirate cultures with bacterial growth in noncritical patients under 18. For multiple cultures within the same episode, the first showing bacterial growth was considered; when multiple isolates were present, the highest bacterial count was used.

Results: We analyzed 552 tracheal aspirate cultures from 62 children. Among the 447 cultures with bacterial growth (81%), 113 (25.3%) were related to episodes of tracheobronchitis. No significant differences were found in bacterial counts > 10 or > 10 CFU/mL between tracheobronchitis episodes and those not meeting criteria for tracheobronchitis or pneumonia (p = 0.405, p = 0.485) or when compared to pneumonia (p = 0.553, p = 0.552). Similarly, in tracheobronchitis episodes, no differences were observed in the bacterial count for variables distinguishing colonization from infection or in clinical severity indicators, except for antibiotic prescriptions, which were significantly higher with bacterial counts > 10 CFU/mL (p = 0.037).

Conclusions: We were unable to demonstrate an association between higher bacterial counts in tracheal aspirate and tracheobronchitis in children with tracheostomy. This raises doubts about the reliability of bacterial count as a diagnostic tool for tracheobronchitis.