Late-Onset Sepsis: Epidemiology, Microbiology, and Controversies in Practice

Area of Science:

• Neonatal Medicine
• Infectious Diseases
• Microbiology

Background:

• Late-onset sepsis (LOS) is a critical factor in neonatal morbidity and mortality.
• The spectrum of causative pathogens for LOS is influenced by gestational age and geographic setting.
• Preterm neonates in resource-limited environments face the highest risk.

Purpose of the Study:

• To review the epidemiology of late-onset sepsis in neonates.
• To highlight the varying causative pathogens based on healthcare setting and gestational age.
• To emphasize the importance of considering non-bacterial causes when cultures are negative.

Main Methods:

• Literature review of studies on late-onset sepsis in neonates.
• Analysis of pathogen prevalence in different geographic and resource settings.
• Synthesis of data on risk factors and common etiologies.

Main Results:

• Gram-negative pathogens, particularly Escherichia coli and Klebsiella species, are predominant causes of LOS in low-resource settings.
• Gram-positive organisms, including coagulase-negative Staphylococci and Staphylococcus aureus, are more common in high-resource settings.
• Non-bacterial pathogens like viruses, fungi, and parasites are potential causes of LOS, especially with sterile bacterial cultures.

Conclusions:

• Understanding regional and gestational age-specific pathogen prevalence is crucial for effective LOS management.
• Diagnostic approaches for LOS should be tailored to the specific clinical setting.
• Consideration of a broader range of pathogens is necessary for accurate diagnosis and treatment of neonatal sepsis.