Processing of Endotracheal tips;
The Microbiology laboratories receive the ET tips for culture and
Antibiotic sensitivity. However Sputum and tracheal aspirates from intubated patients are regularly
cultured in an attempt to diagnose pneumonia which is divided into four broad categories
Community acquired pneumonia (CAP)
Nosocomial or Hospital acquired pneumonia (HAP) and the important subset ventilator-associated
Pneumonia in immunocompromised patients (e.g. HIV, transplant patients)
The controversy continues whether we process endotracheal tips in our laboratories, the question
remains to do or not? -
Expectorated sputum is always contaminated to some degree with oropharengeal organisms.
Because culture of mouth contents (saliva) is not useful in the diagnosis of lung infections, a
microscopic screening process is used to guide culture and interpretation.
So many reject the ET suction tubes and do not screen any endotracheal tube aspirates or suctioned
What we can do next if we do not process the ET tubes
Select the most purulent portion of the specimen for Gram staining and culture. Scan the smear
under low power (10X objective) and examine for epithelial cells and WBCs.
Greater than 10 epithelial cells / low power field – Discard culture plates without examining.
Less than 10 epithelial cells / low power field – Examine and report, with quantitation, routine Gram
stain results. Continue incubation of culture plate
If the number of WBCs is 10 times the number of epithelial cells and there is 3+ or 4+ of a single
morphotype of bacteria, accept the specimen and interpret the culture. (Infection net)
Do realise Tracheo-bronchial aspirates- high sensitivity, however its weakness- as it does not
differentiate between pathogen and colonizer
However the events of infection in neonates are different, Data demonstrate that bacterial
colonization of an indwelling object in the neonatal airway increases with the duration of
intubation. Furthermore, 4 days seems to represent a critical period in the formation of such
colonization (possibly in the form of a biofilm)
Please observe the culture plates from an ET tube form a patient with Head injury on
pulmonary ventilation, and put on several new generations of Antibiotics, A careless
reporting from this culture plates will be harmful to the present patient, if not interpreted
judiciously as it is difficult to diagnose which is a real pathogen. Have wisdom before taking
decisions to change the course of Antibiotic regimes after Culturing and doing Antibiograms