In neonatal intensive care units across the United States, invasive Staphylococcus aureus infections that are susceptible to methicillin are more common and more deadly than methicillin-resistant S. aureus infections, according to a report published Oct. 19 in JAMA Pediatrics.
This means infection prevention and control strategies in NICUs should not focus solely on MRSA but should broadly target methicillin-susceptible S. aureus as well, according to Dr. Jessica Ericson of Duke Clinical Research Institute and the department of pediatrics at Duke University, Durham, N.C., and her associates.
©Zoonar RF/Thinkstock.com
To assess the epidemiology of all invasive S. aureus infections among hospitalized neonates, the investigators analyzed data from 348 academic and community NICUs in 34 states during a 15-year period. They reviewed the medical records of a nationally representative sample of 887,910 infants cared for in these NICUs, of whom 3,888 (0.4%) developed 3,978 invasive S. aureus infections.
A total of 2,868 (72%) of these infections were susceptible to methicillin, while 1,110 (27.9%) were methicillin resistant. Thus, methicillin-susceptible organisms caused 2.6 times more invasive S. aureus infections than did MRSA. In the subgroup of approximately 2,500 affected neonates for whom mortality data were available, the rate of in-hospital death was similar between those with susceptible infections (10%) and those with MRSA (12%), Dr. Ericson and her associates reported (JAMA Ped. 2015 Oct. 19. doi:10.1001/jamapediatrics.2015.2380).
In a further analysis that adjusted for gestational age, sex, and race/ethnicity, there was no significant difference in risk of death between neonates who developed susceptible infections and those who developed MRSA infections at 7 days, 30 days, or hospital discharge, they added.
At present, most medical centers consider only MRSA in their screening and decolonization protocols. Given that the absolute numbers of infections and deaths caused by methicillin-susceptible S. aureus exceed those due to MRSA, hospitals should consider expanding their infection control efforts, Dr. Ericson and her associates said.