Which Factors Predict Hospital-Acquired Late-Onset Neonatal Sepsis?

James W. Gray


Pediatr Health. 2008;2(4):477-484. 

In This Article

Abstract and Introduction


Neonates are one of the highest risk groups of hospitalized patients for sepsis. There is a wide variation in the incidence and microbial causes of late-onset neonatal sepsis, owing to differences in both patient populations and standards of care in the individual neonatal units. Stratification according to risk factors is required to allow the meaningful comparison of infection rates between units. Knowledge of risk factors is also important in order to target interventions on high-risk aspects of neonatal care. Few independent risk factors for late-onset sepsis have been identified, the most common being birth gestational age and parenteral nutrition. Further work is required to validate that these observations can be generalized, and that they could, therefore, be used to stratify infection rates in multicenter surveillance schemes.


Neonates represent one of the highest risk groups of hospitalized patients for sepsis, with up to 50% of neonatal intensive care unit (NICU) patients experiencing one or more episodes of sepsis.[1] Neonatal sepsis is an important cause of immediate morbidity and mortality[1] as well as being associated with an increased risk of long-term neurological sequelae,[2] and is also a major contributor to additional healthcare costs.[1] Neonatal sepsis is classified as early- or late-onset. Whereas early-onset neonatal sepsis is usually due to microorganisms that are acquired from the mother antepartum or intrapartum, the pathogens causing late-onset sepsis (LOS) are generally acquired from the postnatal environment.[1] LOS is most important as a nosocomially acquired infection in hospitalized babies. The timing of the transition from early-onset sepsis to LOS is not clear-cut and depends, to some extent, on the individual pathogen. For example, infections with group B streptococci presenting within the first 7 days of life are usually regarded as early-onset (and, therefore, of maternal origin), whereas infections with coagulase-negative staphylococci presenting at any age are likely to have been hospital-acquired.[3] Most studies of risk factors for LOS have been based on the US CDC definition of a nosocomial infection being one that presents 48h or more after admission.[4,5] However, some authors have found that the transition from maternal to nosocomial origin of infection may begin even earlier than this, and have proposed that only very early-onset infections presenting within the first 24 h should be regarded as unequivocally of maternal origin.[1,3]

Although sepsis can also occur in otherwise healthy babies outside the hospital, the etiologies and epidemiology of this condition are different to those of nosocomial LOS,[1] and this condition will not be considered further here. The purpose of this article is to review risk factors for LOS in NICUs, and how an understanding of these might be used to manage the risks of infection and, thus, improve the quality of hospital neonatal care.


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