Clinical analysis of bacterial flora of lower respiratory tract immediately after tracheostomy and during first tube change: A prospective observational study

Abstract

Background: Tracheostomy is a deliberate surgical procedure performed to make an opening in the anterior wall of the trachea and maintaining this opening with the use of a tracheostomy tube. Colonization of the tracheobronchial tree with microorganisms almost always follows tracheal intubation, tracheostomy, or the use of ventilatory tubes. Infection of the tracheostomy wound site frequently occurs after prolonged use of the tracheostomy. Objective of the study was to establish the bacteria colonizing the lower respiratory tract in tracheotomized patients. Materials & Methods: We collected 36 endotracheal tube samples very aseptically. The collected specimen was kept in a sterile container and was sent immediately to microbiology department for culture and sensitivity. This was inoculated in thioglycollate broth and incubated for 24 hours at 37o C. After 24 hours the broth was examined primarily for the evidence of growth of the bacteria by direct gram stain smear. Then the sample was swabbed on the antibiotic disc with the sterile cotton swab as per Clinical and Laboratory Standards Institute (CLSI) standard guideline. Results: A total of 36 tracheostomies were performed during the period of this study. There were 29 (80.55%) males with a male: Female ratio of 4.14:1. The age of the patients ranged from 13 months to 78 years. The mean age was 58.08 ± 19.82 years. Patients with upper airway edema from trauma, burns, infection, or anaphylaxis (30.55%) followed by polytrauma and head injury who underwent tracheostomy (19.44%), congenital CNS malformation or disorders (16.66%) and supraglottic or glottic pathologic condition (eg, infection, neoplasm, bilateral vocal cord paralysis (13.88%). Thirty three out of 31 (86.11%) tracheal suction catheter tip cultures yielded a positive result on Day 7 or more. With respect to the identity of the bacteria studied in these positive cultures, they were mainly Acinetobacter baumanni (27.78%), Klebsiella pneumoniae (22.22%), Ps. Aeruginosa (19.44%), Methicillin-resistant Staphylococcus aureus (MRSA) (11.11%) and Acinetobacter/ Pr. Mirabilis/ Candida albicans (8.33% each). Conclusion: This study is a qualitative assessment of the tracheal flora and its antibiotic sensitivity patterns in patients with short term tracheostomies. The present study demonstrates that tracheostomy is independently associated with lower respiratory colonization which subsequently progresses to lower respiratory tract infection.