Community-Associated MRSA Incidence on the Rise in Children

Jenni Laidman

September 23, 2013

Community-associated (CA) invasive methicillin-resistant Staphylococcus aureus (MRSA) is on the rise in children, particularly in infants younger than 90 days and in black children, according to a report published online September 23 in Pediatrics.

The study, by Martha Iwamoto, MD, MPH, from the Centers from Disease Control and Prevention (CDC), Atlanta, Georgia, and colleagues, was in sharp contrast to a recent study showing steep declines in adult cases of hospital-onset and healthcare-associated community-onset MRSA and a slight drop in community-associated infection.

In the current analysis, Dr. Iwamoto and colleagues used laboratory-confirmed MRSA cases in the Active Bacterial Core Surveillance database of 9 geographic regions representing some 4.4 million children younger than 18 years to track the increased risk for MRSA in children.

Incidence of CA-MRSA in children rose from 1.1 case per 100,000 children in 2005 to 1.7 cases per 100,000 in 2010, with a modeled yearly increase, adjusted for race and age, of 10.2% (95% confidence interval [CI], 2.7% - 18.2%; P = .007).

Age-, race-, and sex-adjusted MRSA rates were higher among infants aged 3 to 90 days in 2010, at 43.9 cases per 100,000 children, compared with older infants and children (2.0 cases per 100,000 children). The adjusted incidence of invasive MRSA among black children was higher than among children of other races, with 6.7 cases per 100,000 in 2010 for black children compared with 1.6 cases per 100,000 for children of other races. The authors reported no significant trends for healthcare-associated community onset and hospital-onset cases.

"The household is the major vehicle of spread for MRSA strains now," Robert Daum, MD, principal investigator at the University of Chicago MRSA Research Center in Illinois, told Medscape Medical News. Dr. Daum was not involved with the current study. "A decade and a half ago the epidemiology of MRSA underwent a huge change. It's become a community pathogen and arises in patients with no exposure to healthcare."

He continued, "People think MRSA is a problem with dirty hospitals, but not anymore. And it hasn't been for a decade and a half now. Healthcare-associated MRSA [infections] are decreasing in number. And that's been exciting to watch. But now we have to understand that we need a targeted program to help people in households reduce the spread."

"The increase in rates of CA-MRSA in children is concerning," the study authors write. "Current prevention strategies for CA-MRSA focus on education and behavior change aimed at improving hygiene, and it is unknown whether these strategies are effective or have been widely adopted."

Of 876 pediatric MRSA cases analyzed, the researchers found that 298 (35%) were hospital-onset, 196 (23%) were healthcare-associated community-onset, and 363 (42%) were CA.

Median age at the time of infection was 2.1 years (range, 0 days - 17 years), with 39% of cases occurring among infants younger than 1 year. Most (91%) children with MRSA were hospitalized. Fifty-three cases (6%) resulted in death.

Sixty-eight percent (565/834) of children with invasive MRSA had an underlying medical condition, including prematurity (19%), a dermatologic condition such as eczema or abscesses (18%), asthma (8%), congenital disorder (4%), renal disease (2%), and malignancy (2%).

More than 80% of the hospital-onset and healthcare-associated community-onset MRSA cases were in patients with underlying conditions compared with half of the CA cases. The proportion of CA infections was greatest in children aged 5 to 10 years of age, at 71% (92) of the 130 infections in that age group.

The authors and Dr. Daum have disclosed no relevant financial relationships.

Pediatrics. Published online September 23, 2013. Abstract


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.