Johns Hopkins to test all children for 'superbugs'

Apr 17 2007

Infection control and critical care experts at The Johns Hopkins Hospital have ordered testing for the two most common hospital superbugs for every child admitted to its pediatric intensive care unit.

The more stringent admission screening methods for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) go well beyond standard hospital practices, where tests are only ordered after symptoms or early signs of infection appear.

The new hospital practice was introduced March 1 after a study conducted at Hopkins last year showed that more frequent screening detected many more carriers of the germs before their presence led to infection or the germs spread to others.

Admission screening is already standard at Hopkins for adults admitted to intensive care units.

Health experts fear spread of these particular bacteria because they have developed resistance to the antibiotic drugs most commonly used to combat them. Though infections caused by these bacteria are rarely fatal, carriers of either bug are at greater risk for more dangerous infections.

Results from the study, to be presented April 16 at the annual meeting of the Society of Health Care Epidemiology of America (SHEA) in Baltimore, are believed among the first to make a case for better screening in efforts to slow spread of the germs in hospitalized children.

The study compared the effectiveness of weekly screening to current practices for ordering tests and found the weekly model to be many times more effective than standard risk monitoring, in which the highly contagious bacteria are looked for after patients develop skin rash, fever or pain.

Weekly swab testing and bacterial growth cultures were done on nearly 330 patients in the hospital's pediatric intensive care unit for four months. Results were compared to findings of cultures obtained from patients showing possible signs or symptoms of infection. All patients were under age 18.

The weekly testing for MRSA, the most common superbug, detected more than half of young patients who were carrying the germ (54 percent, or one and a half times as many) than were detected through routine testing, which missed 35 percent of those with MRSA. Results for detecting VRE, a lesser known but still common superbug, were six times higher with weekly testing than with routine testing, which missed 82 percent of those with VRE. Like most bacteria, hospital superbugs are picked up through direct contact, by touching someone or a surface with it.

"The results were quite clear to us: Aggressive patient safety programs should consider testing on admission as standard practice," says study senior author and hospital epidemiologist Trish Perl, M.D. Perl and her team, however, will wait for evidence of improved patient safety before making any national recommendations to government agencies and other hospitals.

Perl is past president of SHEA and will be presenting at the four-day conference, expected to attract 1,200 infectious disease specialists, epidemiologists, nurses and hospital administrators to the city.

"We need to find patients who have these bacteria on them and who, as such, are not only at risk of personal infection, but also pose a serious threat of infection to other patients and hospital staff," she says.

According to Perl, a professor of medicine and pathology at The Johns Hopkins University School of Medicine, patients found to be infected or to be a carrier before infection has set in are placed in isolation for the remainder of their stay. Wound care is done only in designated, confined treatment spaces or separate rooms, and hospital staff must take special precautions between treatments, such as cleaning equipment and furniture with strong disinfectants and wearing disposable gloves, masks and gowns.

"Children are more vulnerable to the problem of antibiotic resistance because their bodies are not fully developed to fight off illness and because fewer drugs are FDA approved for use in children," says Aaron Milstone, M.D., a pediatric infectious diseases research fellow at Hopkins who led the study.

Vancomycin (Vancocin) is currently the only FDA-approved drug for MRSA in children, and only one drug, linezolid (Zyvox), is approved in pediatrics for VRE.

Milstone says children admitted to Hopkins are increasingly identified as harboring MRSA or VRE, with recent reports from the intensive care unit showing four times as many children with MRSA and twice as many with VRE than five years ago. These reports and others led the Hopkins team to conduct the study. In 2006, the Joint Commission on Accreditation of Healthcare Organizations (now known only as the Joint Commission) estimated that 70 percent of the bacteria that cause infections for 2 million hospitalized Americans each year are resistant to at least one of the drugs most commonly used to treat them.