Frequently Asked Questions

How widespread is the problem of hospital-acquired infections (HAIs)? 

Between 5 and 10 percent of all patients contract at least one hospital-acquired infection—also known as a healthcare-associated infection or nosocomial infection—during their stay in an acute care hospital.  According to estimates from the National Nosocomial Infections Surveillance (NNIS) system, in 2002, approximately 1.7 million cases of HAIs and 99,000 associated deaths occurred in U.S. hospitals, leading to extra costs of up to $6.5 billion each year.  While the CDC estimated in 1995 that approximately 1.9 million cases of HAIs occurred in hospitals, differences in data collection methods make comparisons between 1995 and 2002 difficult.  However, one trend is clear: the infections are becoming more complicated to treat as their resistance to antibiotics grows.

How pervasive is antibiotic resistance among HAIs?

Infections acquired in hospitals are becoming more virulent and more resistant to the antibiotics typically used to fight them.  One of the deadliest types of antibiotic-resistant bacteria is methicillin-resistant Staphylococcus aureus, commonly referred to as MRSA.  The percentage of Staph infections that are resistant to antibiotics has risen from 22 percent in 1997 to over 60 percent in 2007.  The Centers for Disease Control estimates that MRSA kills approximately 19,000 people per year.  Prevalence of other multidrug-resistant bacteria, or "superbugs", is also increasing, including that of vancomycin-resistant enterococci (VRE) which, in 1997, was found in approximately 15 percent of hospital patients (up from less than 1 percent in 1990).  Clostridium difficile (C. diff), another dangerous superbug, is also on the rise; CDC estimates there are 500,000 cases annually in the U.S., up from 150,000 cases in 2001.

How can MRSA infections be prevented?

There is debate over the effectiveness of different MRSA prevention methods used in hospitals and other healthcare facilities.  Various combinations of interventions can be used, including improved hand hygiene, patient contact precautions, active surveillance and environmental cleaning; according to a CDC report, there is evidence that each of these methods have worked at reducing infection incidents.  

One of the more questionable yet agressive approaches is active surveillance—or, screening patients for presence of the MRSA bacteria upon admission.  This screening can be implemented universally or can target specific high-risk patients.  It is done, ideally, so carriers of infection-causing bacteria can be isolated and treated.  A recent Journal of the American Medical Association article concluded that universal active surveillance programs did not reduce MRSA infections.  However, an article by the Annals of Internal Medicine found that hospital-wide MRSA surveillance did significantly reduce the number of infections.

Because even simple prevention strategies can be overlooked by physicians, recent research has focused on ways to institutionalize these prevention measures to encourage their consistent use throughout a facility.  A recent statewide safety initiative in Michigan, called "Keystone ICU", was funded by the Agency for Healthcare Research and Quality (AHRQ) and sought to change and sustain provider behavior in 130 Intensive Care Units (ICUs) throughout the state.  The program's results found that the interventions, including a centralized team-based education program, nearly eliminated catheter-related bloodstream infections over a period of 18 months.  

Hospitals can also aim to prevent or reduce the overall antibiotic resistance of infection-causing bacteria.  CDC has developed the Campaign to Prevent Antimicrobial Resistance in Healthcare Settings to disseminate guidance on prevention of bacteria transmission and the prudent use of antimicrobials.