To describe trends in the incidence of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children during 2005–2010.
We evaluated reports of invasive MRSA infections in pediatric patients identified from population-based surveillance during 2005–2010. Cases were defined as isolation of MRSA from a normally sterile site and classified on the basis of the setting of the positive culture and presence or absence of health care exposures. Estimated annual changes in incidence were determined by using regression models. National age- and race-specific incidences for 2010 were estimated by using US census data.
A total of 876 pediatric cases were reported; 340 (39%) were among infants. Overall, 35% of cases were hospital-onset, 23% were health care–associated community-onset, and 42% were community-associated (CA). The incidence of invasive CA-MRSA infection per 100 000 children increased from 1.1 in 2005 to 1.7 in 2010 (modeled yearly increase: 10.2%; 95% confidence interval: 2.7%–18.2%). No significant trends were observed for health care–associated community-onset and hospital-onset cases. Nationally, estimated invasive MRSA incidence in 2010 was higher among infants aged <90 days compared with older infants and children (43.9 vs 2.0 per 100 000) and among black children compared with other races (6.7 vs 1.6 per 100 000).
Invasive MRSA infection in children disproportionately affects young infants and black children. In contrast to reports of declining incidence among adults, there were no significant reductions in health care–associated MRSA infections in children. Concurrently, the incidence of CA-MRSA infections has increased, underscoring the need for defining optimal strategies to prevent MRSA infections among children with and without health care exposures.
Comments
Selecting empiric antimicrobial therapy in the era of MRSA
Re: "Trends in Invasive Methicillin-Resistant Staphylococcus aureus Infections" Iwamoto, et al., Pediatrics 2013; 132:e817-e824.
Jennifer L. Goldman MD and Mary Anne Jackson MD
We were interested in the manuscript by Iwamoto et al describing recent trends in invasive methicillin-resistant Staphylococcus aureus (MRSA) infections among pediatric patients. The authors report that the incidence of MRSA infections in children has not demonstrated a significant reduction from 2005-2010. Young infants were most affected by hospital-onset infection. Across all epidemiologic categories, children < 5 years and black children were at increased risk of infection.
The incidence of invasive MRSA is somewhat challenging to interpret without identifying the overall incidence of invasive S. aureus infections as methicillin-susceptible Staphylococcus aureus (MSSA) must be considered. At our pediatric hospital, MSSA accounts for nearly two-thirds of invasive S. aureus infections by year. Furthermore, our MSSA isolates have an increased risk for clindamycin resistance as compared to MRSA. MSSA has been recognized to cause more deep-seated infections as compared to MRSA.[1]
As clinical and epidemiologic factors are typically not helpful in predicting MSSA or MRSA community acquired infection, [2] it is critical to optimize empiric antimicrobial therapy when treating a child with a presumptive S. aureus infection. Although MRSA may not be on the decline, MSSA likely continues to account for significant disease. Consideration of utilizing a B-lactam for effective MSSA bactericidal coverage in addition to MRSA therapy should be considered as vancomycin is considered inferior to B-lactams for the treatment of MSSA bacteremia [3] and adequate therapeutic vancomycin levels can be difficult to achieve in the pediatric population.
1. Sattler, C.A., E.O. Mason, Jr., and S.L. Kaplan, Prospective comparison of risk factors and demographic and clinical characteristics of community-acquired, methicillin-resistant versus methicillin-susceptible Staphylococcus aureus infection in children. Pediatr Infect Dis J, 2002. 21(10): p. 910-7.
2. Miller, L.G., et al., Clinical and epidemiologic characteristics cannot distinguish community-associated methicillin-resistant Staphylococcus aureus infection from methicillin-susceptible S. aureus infection: a prospective investigation. Clin Infect Dis, 2007. 44(4): p. 471-82.
3. Liu, C., et al., Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children. Clin Infect Dis, 2011. 52(3): p. e18-55.
Conflict of Interest:
None declared