Early neutropenia is not associated with an increased rate of nosocomial infection in very low-birth-weight infants

Background: Evidence is contradictory whether very low-birth-weight (VLBW, birth weight < 1500 g) infants with early neutropenia (NP), especially those born to mothers with preeclampsia experience a greater incidence of nosocomial infection (NI). Objective: To investigate whether NP within the first 7 days of life is a risk factor for NI in VLBW infants. Methods: Over a 42-month period, we identified all VLBW infants born at <= 34 weeks gestation who survived for more than 72 h. Infants who had no evidence of early infection, who had at least one complete blood count performed in the first week of life, and who were not given prophylactic recombinant human granulocyte colony-stimulating factor (rhG-CSF) were included in this retrospective study. Early NP was defined as an absolute neutrophil count less than 1500 per mu l at any time during the first week of life. NI was defined as the culture of a bacterial or fungal pathogen from a sterile body fluid that was obtained after 72 h of life in an infant with one or more clinical signs of infection. Results: A total of 338 VLBW infants were reviewed. Of those, 51 infants were excluded because of death or onset of an infection before 72 h of age, lack of a complete blood count in the first week of life or treatment with rhG-CSF. Of the remaining 287 infants, NI occurred in 11 of 77 (14.3%) infants with early NP compared to 42 of 210 (20.0%) infants without early NP (P = 0.31). Infants who developed NI were smaller and less mature, had lower Apgar scores, were more frequently instrumented with central lines and required a longer duration of parenteral nutrition compared to infants without NI. Infants with NI also had a higher mortality and a greater incidence of necrotizing enterocolitis, severe intraventricular hemorrhage and threshold retinopathy of prematurity. However, using stepwise multivariate logistic regression analysis, only the duration of parenteral nutrition and gestational age were significant risk factors for NI. Conclusion: Our data do not support the hypothesis that early NP increases the risk for NI in VLBW infants.