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Updated: Mar 31, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Burden of Invasive Staphylococcus aureus Infections in Hospitalized Infants
Jessica E Ericson1, Victor O Popoola2, P Brian Smith3
1Duke 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.
Importance:
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.
Objectives:
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.
Design, Setting, And Participants:
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.
Exposure:
Invasive S aureus infection.
Main Outcomes And Measures:
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 And Relevance:
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.
Insights
Methicillin-susceptible Staphylococcus aureus (MSSA) causes more infant infections and deaths than methicillin-resistant S aureus (MRSA). However, infant mortality rates are similar for both invasive MRSA and MSSA infections. Prevention strategies should target both strains.
Area of Science:
- Neonatal Medicine
- Infectious Diseases
- Pediatric Critical Care
Background:
- Staphylococcus aureus infections in hospitalized infants are linked to increased mortality, morbidity, and prolonged hospital stays.
- Limited data exist on the overall burden of S aureus disease in this vulnerable population.
Purpose of the Study:
- To compare the 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 attributed to MRSA.
- To contrast the risk of death following invasive MRSA versus MSSA infections.
Main Methods:
- A multicenter retrospective study analyzed data from 348 neonatal intensive care units.
- The cohort included 3888 infants with invasive S aureus infections discharged between 1997 and 2012.
- Key outcomes measured were infection incidence, infant characteristics, and mortality rates.
Main Results:
- A total of 3978 invasive S aureus infections (2868 MSSA, 1110 MRSA) were identified.
- The proportion of MRSA infections increased from 1997 to 2006, then moderately decreased.
- While MSSA caused more infections and deaths, the mortality proportions and adjusted risks of death were similar between MRSA and MSSA invasive infections.
Conclusions:
- Infant mortality rates are comparable for invasive MRSA and MSSA infections.
- MSSA is responsible for a greater number of infections and deaths in infants compared to MRSA.
- S aureus infection prevention measures should encompass both MSSA and MRSA.
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