The utility of tracheal aspirate cultures in the immediate neonatal period

Abstract

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 ¼ 139).Result: In total, 9 of 139 (6.5%) TA cultures were positive for pathogenic bacterial growth. Maternal fever (relative risk (RR) ¼ 7.7, P<0.04) and clinical chorioamnionitis (RR ¼ 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 À3 , 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.

Lack of utility of tracheal aspirates in the management of suspected pneumonia in intubated neonates

“…11 In neonates, the use of TAs to diagnose pneumonia may be useful when aspirates are collected in the immediate neonatal period, with an overall positive culture incidence of 6.5% in tracheal aspirate cultures obtained 12 hours after birth. 12 Interestingly, the Gram stain results in this study demonstrated low specificity and sensitivity for pathogen growth, consistent with our results, in which we found no statistical association with the number of WBCs on the Gram stain. 12 In contrast, in neonates who have been chronically intubated, the risk of colonization increases, therefore increasing the chances of obtaining a positive tracheal aspirate culture.…”

“…12 Interestingly, the Gram stain results in this study demonstrated low specificity and sensitivity for pathogen growth, consistent with our results, in which we found no statistical association with the number of WBCs on the Gram stain. 12 In contrast, in neonates who have been chronically intubated, the risk of colonization increases, therefore increasing the chances of obtaining a positive tracheal aspirate culture. 13,14 One study in ventilated preterm infants using molecular identification of bacteria in tracheal aspirates found that in the first 72 hours after birth, most tracheal aspirate cultures had undetectable bacterial loads.…”

Infection control and other stewardship strategies in late onset sepsis, necrotizing enterocolitis, and localized infection in the neonatal intensive care unit

“… 126 The presence of white blood cells on tracheal aspirates has also been shown to have low specificity (54%) and sensitivity (67%) for VAP, even when there is bacterial growth on culture. 127 …”

Association of Endotracheal Aspirate Culture Variability and Antibiotic Use in Mechanically Ventilated Pediatric Patients

“…1,4,5 The results from EACs are relatively nonspecific for infection and may be unreliable. [6][7][8][9][10][11][12][13][14][15][16] Sample collection and quality of specimens are variable, which may affect results. 16,17 Endotracheal secretion samples are from a nonsterile site, making the differentiation between colonization and infection in the culture challenging.…”