Mortality rate for children with MRSA remains low despite rise in infections

Methicillin-resistant Staphylococcus aureus infections may be increasing among children, according to findings from a recent study conducted in several children’s hospitals in the United States.

Researchers gathered data for the retrospective, observational study from the Pediatric Health Information System. They analyzed hospital discharge data from children younger than 18 who had S. aureus infections between Jan. 1, 2002 and Dec. 31, 2007.

Data were available for 57,794 children, 29,309 of whom had MRSA. The median age of patients was 3.1 years.

There were 6.7 cases of MRSA per 1,000 hospital admissions in 2002 and 21.1 cases per 1,000 admissions in 2007 (P=.02, by test for trend). Methicillin-susceptible S. aureus infections remained stable, with 14.1 cases per 1,000 patient-days in 2002 and 14.7 cases per 1,000 patient-days in 2007 (P=.85, by test for trend).

Skin and soft-tissue infections were observed in 23,280 of 38,123 patients whose type of infection was identified.

MRSA was associated with skin and soft-tissue infections, pneumonia, osteomyelitis and bacteremia.

There was a 1% mortality rate for children who had been hospitalized with MRSA, according to the data.

Gerber J . Clin Infect Dis. 2009; 49: 65-71.

This article provides additional information reaffirming what has been reported from several single institutions; that MRSA infections in otherwise healthy U.S. children increased dramatically in the early 2000s and continues to be on the increase.

This study shows that this increase was seen nationally among 33 major children's hospitals. Skin and soft tissue infections predominated as has been reported.

Gerber et al found that overall, S. aureus pneumonia was more common than S. aureus osteomyelitis, whether MSSA or MRSA, but this could not be broken down for community-acquired versus healthcare associated infections. Certainly, that is not the case in our institution for community-acquired MRSA infections where osteomyelitis is by far the most common invasive infection. This likely reflects hospital- acquired pneumonia, especially in the ICUs.

We have also reported an increase in invasive MSSA infections from the community, in part, related to the rise in CA-MSSA isolates with the USA300 background but without the SCCmec element. The high number of children categorized as bacteremia is also of interest. It would be important to know how many of these bacteremias were catheter-related since isolated S. aureus bacteremia without a focus is somewhat unusual in children. The overall mortality rate is not very helpful considering most of these patients had skin and soft tissue infections. Calculating mortality rates for only those patients with serious infections would provide more valuable information.

Sheldon L. Kaplan, MD

IDC Editorial Board