Staphylococcus aureus Infection Rates on the Rise in U.S. Hospitals

BALTIMORE -- Findings presented today at the Society of Healthcare Epidemiology of America annual meeting further demonstrate that there has been a significant increase in Staphylococcus aureus infection rates among patients in U.S. hospitals, resulting in longer hospitalizations and millions of dollars of excess healthcare costs.

Researchers analyzed more than 45 million hospital discharge records and found that from 1998 to 2003 the prevalence of Staph aureus infection among all patients increased at an annual rate of 7.1 percent.  The problem grew even faster among surgical patients; the rate of Staph aureus infection rose 7.9 percent each year for all surgical stays and 9.3 percent each year for orthopedic patients. The studies, which were funded by 3M Health Care, were conducted by lead investigator Dr. Gary Noskin, associate professor of medicine at the Feinberg School of Medicine, NorthwesternUniversity and associate chief medical officer at NorthwesternMemorialHospital.  

Staph aureus causes a wide range of infections, from mild skin infections to life-threatening blood stream infections, said Angela Dillow, PhD, global business manager, 3M Medical Diagnostics. Identifying the bacteria and reducing its spread in hospitals is crucial to improving patient outcomes, and these findings underscore the need to control these infections.  Prior to surgery, about one-third of patients carry Staph aureus in the nose but do not have an infection. It is only if the bacteria enter other parts of the body, through a surgical incision, for example, that they can result in a serious infection.

The researchers also presented findings on the economic impact of Staph aureus infections in hospitals and found that from 1998 to 2003 the economic burden among all Staph aureus-related inpatient stays increased from $8.7 billion to $14.5 billion, an annual increase of 11.9 percent. The costs of Staph aureus for invasive cardiovascular stays and invasive neurological stays rose at 12.4 percent a year and 13.5 percent a year, respectively.

These findings clearly demonstrate the considerable economic implications of Staph aureus infections for hospitals nationwide, said Noskin. It suggests that there could be large cost savings associated with aggressive efforts to prevent patients from becoming infected with these bacteria.

Another abstract submitted by Noskin and colleagues at the meeting examined the economic benefit of screening for Staph aureus from nasal samples.  The study showed rapid pre-admission testing for nasal Staph aureus and subsequent colonization suppression of carriers resulted in an average annual cost savings of approximately $519 million for U.S. hospitals. Researchers analyzed data from the 2003 Nationwide Inpatient Sample and published literature. Primary input variables included the marginal effect of Staph aureus infection on expenditures, prevalence of nasal Staph aureus carriage, sensitivity and specificity of the rapid Staph aureus screening device, efficacy of nasal Staph aureus colonization suppression and cost data.

 Rapid, pre-admission testing of patients could help hospitals better identify patients that are colonized with Staph aureus and in the appropriate setting attempt to decolonize them to help reduce the risk of infection and control costs, said Dillow.