Bacterial colonisation of the endotracheal tube in ventilated very preterm neonates: A retrospective cohort study

Aim: To determine the rate, type and timing of bacterial endotracheal tube (ETT) colonisation in neonates born <32 weeks gestational age (GA); and if bacterial colonisation is associated with chronic lung disease (CLD), septicaemia, length-of-stay or mortality. Methods: All intubated newborns born <32 weeks GA were included. Endotracheal aspirates were routinely obtained three times-per-week. Cohort was divided into three colonisation groups: no growth, normal respiratory flora only, significant bacteria. Logistic regression was performed to identify if ETT bacterial colonisation was associated with CLD, septicaemia or mortality. A general linear model was fitted for length-of-stay. Results: ETT aspirates were sent from 1054 infants: no growth n = 319, only normal respiratory flora n = 357, and significant bacteria n = 378. ETTs became colonised in 70%, most in the first week of life (82%). Most grew normal respiratory flora (642 infants). In those with significant bacteria, 40% grew Gram-negative species;Klebsiellain 34%.Staphylococcus aureusgrew in 104 patients. Adjusted odds ratios for CLD (43% of cohort) compared with no growth were, for normal respiratory flora, 0.58 (95% confidence interval (CI) 0.34-0.99) and, for significant bacteria, 0.48 (95% CI 0.24-0.93). With no overall association between colonisation group and CLD in the adjusted model P= 0.07. The odds of septicaemia (10% of cohort) were 4.50 (95% CI 1.98-10.23,P < 0.001) times greater for significant bacteria compared with no growth. No significant associated was found with mortality or length-of-stay. Conclusions: Bacterial colonisation of ETTs is common. It is associated with more septicaemia. There was no significant association with CLD, longer admission or mortality.