These findings underscore the critical need for enhanced infection control measures in NICUs to protect this vulnerable population.

The incidence of S aureus infections in VLBW infants is alarmingly high, nearly 20 times greater than in infants weighing 1500 grams or more, with rates of 227.1 versus 10.1 per 10,000 infants respectively.

This study highlights the urgent need for new strategies to combat late-onset invasive S aureus infections in NICUs, as existing prevention measures have not yielded significant improvements.

The study analyzed a substantial cohort of 468,201 infants admitted to NICUs across the United States from 2016 to 2021, focusing specifically on late-onset invasive S aureus infections.

Moreover, VLBW infants accounted for 90.4% of the deaths among those infected, highlighting their vulnerability.

Findings revealed that 80.9% of infected infants were born at 32 weeks of gestation or earlier, with 76.5% classified as VLBW and 87.5% requiring central line placements during their NICU stay.

Late-onset infections were defined as positive cultures from various body fluids collected at least four days after birth.

The study also indicated a concerning all-cause mortality rate, showing that infected infants had a mortality rate of 12.1%, significantly higher than the 1.0% rate in matched non-infected infants.

Late-onset invasive Staphylococcus aureus infections pose a significant threat to infants in neonatal intensive care units (NICUs), particularly affecting those with very low birth weight (VLBW) under 1500 grams.

Conducted by Dr. Aaron M. Milstone from Johns Hopkins University, the research was published in JAMA Pediatrics on April 14, 2025.

Overall, VLBW infants represented over 75% of all S aureus infections and the majority of related fatalities in hospitalized settings.

However, the study faced limitations, including potential bias from the convenience sample and challenges in tracking infections that occurred prior to admission or after transfer to other hospitals.