Kids' MRSA cut off at the pass

Johns Hopkins study spurs institution to screen
all ped ICU admissions

By Samuel Jarjour

On March 1, infection control measures got tougher at Johns Hopkins Hospital's pediatric ICU. Now, ICU-admitted kids will, like adults, be routinely screened on admission for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE).

The change in practice comes after a Johns Hopkins study compared estimates of bacterial colonizations based on weekly screening with the current practices. The results, which were presented in mid-April at the annual meeting of the Society of Healthcare Epidemiology of America in Baltimore, suggested that more stringent screening measures would help curb the spread and infection by the common superbugs.

PREVALENCE UNDER THE RADAR
The study, led by Dr Aaron Milstone, an infectious disease specialist at Hopkins, estimated MRSA and VRE prevalence using weekly nasal and rectal cultures collected over a 16-week-period in the pediatric ICU in 330 patients. They also took clinical cultures according to normal protocol. They calculated the prevalence of positive MRSA IDs over the total number of patient-days, detecting a patient density rate of 1.38 cases per 100 patient days — almost two times greater than estimates based on clinical cultures alone. The estimate for VRE was 12 times higher, at 1.22 per 100 patient days, using weekly screening vs clinical cultures.

Based on their findings, they concluded that prevalence of MRSA and VRE in pediatric ICUs could be frequently underestimated when clinical cultures are relied upon. Because of the potential for underestimating, the practice of routine screening was adopted for the high-risk setting of the ICU. "This definitely isn't the standard of practice in most hospitals," notes Dr Milstone. "Testing following the appearance of symptoms and risk factors is the standard, and bacteria are identified once people get sick — but there's no pre-emptive strike," he continues, noting that detecting bacterial colonization in a patient can allow early patient treatment and isolation, preventing infections of other patients and hospital staff.

While the Hopkins researchers examined colonization rates, they have yet to look at whether better identification of MRSA and VRE affects patient care and safety by reducing infections. "The risk of infection in kids colonized by MRSA hasn't been accurately measured, but both MRSA and VRE can cause devastating infections in children," says Dr Milstone. "At this point, MRSA has really jumped out, not just in pediatrics in hospital, but in the community as well, and the source of infection is becoming increasingly difficult to track." He points out that community and hospital associated strains appear to be spreading to each others' respective turf. "It's hard to tell if a carrier brought it in or if they picked it up in the hospital. A routine surveillance method that produces dramatically increased patient isolation could help prevent spreading."

Dr Milstone notes that the next study's outcomes for patient health will determine whether they recommend routine screening measures to other hospitals and government agencies. "We're investigating further, looking at the costs of the new screening measures, including ones associated with surveillance and isolation," he says.

A TAILORED APPROACH
Dr Dorothy Moore of the Montreal Children's Hospital Department of Infectious Diseases isn't so sure the Hopkins program would work here. "MRSA is less common in Canada," she explains. "Local circumstances are very important for this type of thing. We can't screen every child who comes in, or else all we would be doing is screening."

In 2003, the Canadian Nosocomial Infection Surveillance Program reported that 2.4% of patients colonized or infected with MRSA were children. In the general population, the rate of patients with MRSA has risen from 0.46 patients per 1,000 admissions in 1995 to 5.1 per 1000 in 2003.

Bacterial infections specialist Dr Sarah Forgie of the Stollery Children's Hospital (SCH) in Edmonton says they screen patients with specific risk factors, including stay in another hospital prior to admission. "If a person is identified, as a carrier or as infected, we take the standard precautions, which we recommend for all caretakers, including gowns, gloves, masks, handwashing, as well as isolation of infected patients."

STERILIZE THIS
While this seems like basic hospital hygiene, poorly-executed practices can quickly land a hospital in the headlines. In late March, in the small Alberta town of Vegreville, admissions were stopped at St Joseph's General Hospital because of an alleged outbreak of MRSA. Seven patients in the 25-bed hospital, just 40km outside of Edmonton, were found to be infected within one month. "Improper equipment sterilization was the problem there," says Dr Forgie. Alberta's nurse's union says three of the patients with MRSA were already infected when they were admitted.