The utility of tracheal aspirate cultures in the immediate neonatal period

Objective: Determine the contemporary incidence of pathogenic tracheal aspirate (TA) cultures when obtained within 12 h of birth, and to associate TA culture results with specific clinical conditions that increase the risk of infection. Study Design: A retrospective study over a 6-month period of admissions to a single outborn neonatal intensive care unit when a TA sample was collected within 12 h of birth (n = 139). Result: In total, 9 of 139 (6.5%) TA cultures were positive for pathogenic bacterial growth. Maternal fever (relative risk (RR) = 7.7, P<0.04) and clinical chorioamnionitis (RR = 6.4, P<0.02) were significantly associated with pathogenic TA culture results. Infants with a pathogenic TA culture had lower white blood cell counts (7 500 vs 13 900 mm(-3), P<0.05) when compared with infants with a negative culture. In eight of the nine patients with pathogenic cultures, either the mother or the infant received antibiotics before TA sample collection. Conclusion: Early TA culture is a helpful tool in diagnosing pneumonia, especially in certain clinical scenarios, including maternal fever, clinical chorioamnionitis and leukopenia. Administration of antibiotics before sample collection does not seem to preclude culture growth. Journal of Perinatology (2009) 29, 493-496; doi: 10.1038/jp.2009.33; published online 2 April 2009