MRSA Infection Rates Increase Tenfold in Children

Clindamycin use among children hospitalized with S. aureus increased threefold during the past decade, according to a study published online May 17 in Pediatrics. In 1999, the antibiotic was used to treat 21% of S. aureus cases. In 2008, 63% of such infections were treated with the drug.

The antibiotic became popular because it effectively treats methicillin-resistant S. aureus and it can be taken orally, unlike vancomycin, which is only available intravenously, said senior study author Jason Newland, MD. But he said the problem is that physicians are using clindamycin to treat cases of methicillin-susceptible S. aureus, which can be effectively treated with different antibiotics.

Clindamycin "is used a lot. And we've learned that [S. aureus] has an incredible ability to become resistant over time. ... We don't want to overuse clindamycin," said Dr. Newland, director of the Antibiotic Stewardship Program and director of the Office of Evidence Based Practice at Children's Mercy Hospitals and Clinics in Kansas City, Mo. He also is an assistant professor of pediatrics at the University of Missouri-Kansas City School of Medicine.

Liz Power, spokeswoman for Pfizer Inc., manufacturer of Cleocin, said the company supports the responsible use of antibiotics to treat infections. "Resistance is an issue for anyone treating infectious diseases and physicians have to make the best decisions they can with their patients."

Researchers recommend that physicians monitor antibiotic susceptibilities in their communities and practices to help them determine what drug they should use to treat S. aureus infections.

For this study, researchers examined data on 64,813 children younger than 18 who were hospitalized with an S. aureus infection between Jan. 1, 1999 and Dec. 31, 2008. The study involved 25 U.S. children's hospitals (pediatrics.aappublications.org/cgi/content/abstract/peds.2009-2867v1/).

The study said the incidence of S. aureus infection more than doubled among children. The increase was driven largely by MRSA, which increased tenfold during the study period.

In 1999, there were 2.0 cases of MRSA per 1,000 admissions, compared with 20.7 cases in 2008. During the same period, the MSSA infection rate remained relatively stable at about 12 cases per 1,000 admissions.

In the study period, 29,571 children were hospitalized with MRSA, and 374 died. Researchers are unsure whether the infection caused the children's deaths. In 2005, the infection was associated with the deaths of more than 18,000 adults and children nationwide, according to the Centers for Disease Control and Prevention.

Study co-author Theoklis Zaoutis, MD, said he has seen a similar increase in MRSA infections at the Children's Hospital of Philadelphia, where he works. In 2000, about 20% of the hospital's S. aureus infections were MRSA. Now, he said, the superbug accounts for more than half of S. aureus infections.

"We see probably two to three MRSA infections per shift in the emergency department here. The prevalence is huge," said Dr. Zaoutis, associate chief of the division of infectious diseases at the hospital.