Burden of Invasive Staphylococcus aureus Infections in Hospitalized Infants.
OBJECTIVE
Staphylococcus aureus is a frequent cause of infection in hospitalized infants. These infections are associated with increased mortality and morbidity and longer hospital stays, but data on the burden of S aureus disease in hospitalized infants are limited.


OBJECTIVE
To compare demographics and mortality of infants with invasive methicillin-resistant S aureus (MRSA) and methicillin-susceptible S aureus (MSSA), to determine the annual proportion of S aureus infections that were MRSA, and to contrast the risk of death after an invasive MRSA infection with the risk after an invasive MSSA infection.


METHODS
Multicenter retrospective study of a large, nationally representative cohort at 348 neonatal intensive care units managed by the Pediatrix Medical Group. Participants were 3888 infants with an invasive S aureus infection who were discharged from calendar year 1997 through calendar year 2012.


METHODS
Invasive S aureus infection.


METHODS
The incidence of invasive S aureus infections, as well as infant characteristics and mortality after MRSA or MSSA infection.


RESULTS
The 3888 infants had 3978 invasive S aureus infections (2868 MSSA and 1110 MRSA). The incidence of invasive S aureus infection was 44.8 infections per 10,000 infants. The yearly proportion of invasive infections caused by MRSA increased from calendar year 1997 through calendar year 2006 and has moderately decreased since then. Infants with invasive MRSA or MSSA infections had similar gestational ages and birth weights. Invasive MRSA infections occurred more often at a younger postnatal age. For infants with available mortality data, more infants with invasive MSSA infections (n = 237) died before hospital discharge than infants with invasive MRSA infections (n = 110). The proportions of infants who died after invasive MSSA and MRSA infections were similar at 237 of 2474 (9.6%) and 110 of 926 (11.9%), respectively (P = .05). The adjusted risk of death before hospital discharge was similar after invasive MSSA and MRSA infections (risk ratio, 1.19; 95% CI, 0.96-1.49). The risks of death at 7 and 30 days after invasive infection were similar between infants with invasive MSSA infection and infants with invasive MRSA infection.


CONCLUSIONS
Infant mortality after invasive MRSA and MSSA infections is similar, but MSSA causes more infections and more deaths in infants than MRSA. Measures to prevent S aureus infection should include MSSA in addition to MRSA.
Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina2Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina3currently with the Department of Pediatrics, Penn State College of Medicine.
Jessica E
JE
Ericson
Division of Infectious Diseases, Department of Pediatrics, The Johns Hopkins University, Baltimore, Maryland.
Victor O
VO
Popoola
Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina2Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina.
P Brian
PB
Smith
Department of Economics, Clemson University, Clemson, South Carolina.
Daniel K
DK
Benjamin
Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina6Department of Medicine, Duke University School of Medicine, Durham, North Carolina.
Vance G
VG
Fowler
Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina2Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina.
Daniel K
DK
Benjamin
Pediatrix Medical Group, Sunrise, Florida.
Reese H
RH
Clark
Division of Infectious Diseases, Department of Pediatrics, The Johns Hopkins University, Baltimore, Maryland.
Aaron M
AM
Milstone
D017281:Cost of Illness; D005260:Female; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000401:mortality; D013211:Staphylococcus aureus / Q000302:isolation & purification*