Microbial Differences in Tracheal Cultures

Abstract

Background: When tracheostomy-dependent pediatric patients are hospitalized due to tracheitis, pneumonia, or other respiratory infections, there is insufficient evidence to support tracheostomy tube replacement prior to obtaining a respiratory culture. The lack of evidence has led to inconsistent practice across the institution and may have implications regarding antibiotic exposure for these patients. The purpose of this study was to investigate differences in microbial growth between cultures obtained before and after changing the tracheostomy tube.

Methods: This quasi-experimental, IRB approved prospective cohort study enrolled 38 tracheostomy-dependent pediatric patients [between the ages 0-17.99] accompanied by a consenting caregiver presenting in the Emergency Department or acute medical-surgical unit. Pre-tracheostomy and post-tracheostomy tube change respiratory cultures were obtained and examined. Descriptive statistics were done to characterize the sample in terms of demographics, details of presenting signs and symptoms, and differences in the profile of microorganisms in the pre- and post-tracheostomy change cultures. Chi-Square analyses using a McNemar’s test were performed to analyze differences in gram stain results in the pre- and post-cultures.

Results: Among 60 eligible patients screened, 11 were excluded due to lack of team member availability; of the 49 approached, 42 were enrolled, while seven declined. The total number of participants with complete data is 38, and four participants were withdrawn for the following reasons: failure to meet inclusion criteria after preliminary screening, loss of specimen sample by laboratory, and inability to perform study procedures due to lack of time and patient acuity. The WBC amount seen in the pre- and post-cultures was significantly different (P = 0.012). Specifically, 10 patients (26%) were noted to have moderate or many WBCs in their pre-tracheostomy change culture and subsequently rare to few WBCs observed in their post-culture. In the pre-cultures, 49 organisms were identified (35 gram negative, 13 gram positive, and one fungus), versus 34 in the post-cultures (25 gram negative, 9 gram positive, 0 fungus).

Conclusions: We observed differences in cell count and bacterial growth when pre- and post-trach change cultures were compared. Given these results, changing the tracheostomy tube prior to obtaining a respiratory culture should be considered. Future research is needed to confirm these findings with a larger sample size.