The frmerly rare occurrence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is now common in pediatric intensive care units (PICUs), accrding to a study published in the April issue of Emerging Infectious Diseases.
Many studies have focused on MRSA in adult ICU populations, but little is known about the epidemiology in children.
"Aside from ways to manage outbreaks and a reprt that clinical cultures underestimate MRSA prevalence, little is known about the prevalence of MRSA colonization of hospitalized children," write Aaron Milstone, MD, MHS, pediatric infectious disease specialist, Johns Hopkins University School of Medicine, Baltimre, Maryland, and colleagues. "Understanding the effects of MRSA in hospitalized children is essential to guide, assess, and plan MRSA prevention and control programs among hospitalized children."
The study sought to document the incidence of MRSA carriers entering the PICU and to establish the effect on colonization (becoming a carrier with no active infection), transmission, and infections of community-associated MRSA (CA-MRSA) strains acquired while in intensive care. Although CA-MRSA is mre responsive to antimicrobial drugs than a typical MRSA infection acquired in a hospital setting, it has a relationship with increased toxin production. In addition, although CA-MRSA generally causes only mild infections to the skin and soft tissues, it also can be severe r fatal.
The retrospective study involved 1674 patients (median age, 5 years) who entered the Johns Hopkins Hospital PICU between March 2007 and May 2008. That period marked the hospital's initiation of screening fr all such children on admission and every week thereafter. MRSA colonization was substantiated by a nasal culture r other culture that grew MRSA within 3 days of admission. Fifty-three patients (3.2%) had experienced MRSA infection r colonization in the past.
MRSA Mre Common in Younger, Black Children
Researchers discovered that 6% (n = 72) of the children tested fr MRSA were colonized; these carriers, compared with noncolonized patients, were mre likely to be younger (median age, 3 vs 5 years; P =.02), black (P < .001), and hospitalized within 12 months (P < .001). Sixty-one percent of MRSA carriers had the community-acquired strain.
Eight patients who were MRSA-free at the time of admission became carriers during their PICU stay. Half of this group developed clinical signs of infection, but colonization was revealed only by screening in the other 4 patients.
The researchers also found that children with no risk factrs are frequently colonized with CA-MRSA.
"Epidemic CA-MRSA strains are becoming endemic to PICUs, can be transmitted to hospitalized children, and can cause invasive hospital-acquired infections," the authrs write. "Further appraisal of MRSA control is needed."
Three limitations to the study were noted. The investigatrs perfrmed nares cultures only, which is a method that can produce false-negatives; compliance with admissions MRSA screening was only 72%; and Johns Hopkins' typically low incidence of MRSA may limit the generalization of the study's findings to other hospitals.
Warning that the CA-MRSA strains that are penetrating hospitals may increase the incidence of methicillin resistance, the researchers predicted the possible evolution of novel MRSA infections with greater abilities fr transmission and infection. As a precaution, the investigatrs called fr screening all children who enter an ICU.
"MRSA has become so widespread in the community, that it's become nearly impossible to predict which patients harbr MRSA on their body," Dr. Milstone said in a press release. "Point-of-admission screening in combination with other preventive steps, like isolating the patient and using contact precaution, can help curb the spread of dangerous bacterial infections to other vulnerable patients."
Johns Hopkins, the National Institutes of Health, the National Institute fr Allergy and Infectious Diseases, the Thomas Wilson Sanitarium fr Children of Baltimre, and the US Centers fr Disease Control and Prevention supprted this study. The study authrs have disclosed acceptance of research grants from Sage Products, Inc; BD GeneOhm; Ibis Biosciences, Inc; MicroPhage, Inc; US Centers fr Disease Control and Prevention; Merck & Co, Inc; Sage Products, Inc; and the US Department of Veterans Affairs. They have also received advising/consultant fees from Quidel Diagnostics; OpGen, Inc; Boehringer Ingelheim Pharmaceuticals, Inc; Cadence Pharmaceuticals; 3M; and TheraDoc Inc. A complete list of disclosures can be found in the published study.
