CDC will answer critics with new MRSA guidelines

Active surveillance culture stance similar to SHEA

The Centers for Disease Control and Prevention will soon issue new guidelines on multidrug resistant pathogens that include a more aggressive approach to the controversial issue of active surveillance, Hospital Infection Control has learned.

The long-awaited guidelines likely will be posted on-line to hasten the process, which has been delayed by a protracted federal review involving other government agencies. It was unclear as this issue went to press whether the guidelines will be issued separately or along with the entire new patient isolation guidelines, which have been in a similar bureaucratic limbo.

At any rate, the guidelines will allow CDC to respond to critics who have blasted the agency because draft versions of the document did not emphasize active surveillance cultures as recommended by the Society for Healthcare Epidemiology of America (SHEA). SHEA calls for culturing the nares of targeted patients on admission or periodically thereafter to detect and isolate the reservoir of resistant organisms.1 The SHEA guidelines recommend the practice so patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) can be placed in contact isolation rather than serving as an undetected reservoir to spread the pathogens to other patients. A 2004 draft of the patient isolation guidelines by the CDC's Healthcare Infection Control Practices Advisory Committee (HICPAC) called for more aggressive measures such as active surveillance only in the face of ongoing transmission or if prevalence exceeded institutional goals.2 That language has been toughened up to include active surveillance cultures if the institution is not decreasing MRSA rates or if it has no MRSA and is trying to prevent the pathogen from getting established.

"Those situations are very similar to what the SHEA guidelines recommend," says Denise Cardo, MD, director of the CDC division of healthcare quality improvement. "We see the importance of publishing this guideline so instead of people talking about what they think we are recommending they can see that what we are recommending will really make a difference in terms of preventing multidrug-resistant organisms. Surveillance is part of the recommendations but it is not the only recommendation in the guideline. The guidelines are for a comprehensive approach to multidrug-resistant organisms."

Indeed, the discrepancy between the SHEA and CDC guidance has been pounced on by agency critics such as Betsy McCaughey, PhD, former lieutenant governor of New York and founder of the Committee to Reduce Infection Deaths (RID) in New York City.

"Their guidelines are too lax," she tells HIC. "Year after year for the last 25 years, the CDC has tracked the rapid rise in drug-resistant infections, but they have done too little to stop it." Moreover, in a recently published paper warning that hospital infections may be the "next asbestos" in terms of liability, McCaughey wrote: "Astoundingly, most U.S. hospitals don't routinely test incoming patients for MRSA. Seventy to 90% of patients carrying MRSA are never identified. Knowing which patients are sources of infection is key to stopping the spread. If you're placed in a semiprivate room with a patient carrying MRSA, you're at increased risk of infection. . . . Will hospitals that fail to test incoming patients and isolate those testing positive be deemed negligent and held liable when a patient contracts a deadly MRSA infection?" 3

To swab or not to swab

The MRSA screening issue has taken on such a life of its own that the larger drivers of drug resistance like inappropriate and prolonged antibiotic administration are being somewhat overshadowed.

"It is not an issue for those of us who are accustomed to discussing this, but if you are not careful the discussion really gives you the impression that antimicrobial resistance is being caused by inadequate culturing," says Michael Bell, MD, a medical epidemiologist in the CDC division of healthcare quality promotion. "This swab or don't swab issue is really a small part of the iceberg. It's kind of like lung cancer. You don't say you get lung cancer because you are not doing enough X-rays. You get it because you smoke too much."

However, the liability overtones raised by McCaughey and others are concerning to clinicians, particularly those who say the problem is much more complex than an "either/or" decision on active screening. William Schaffner, MD, chairman of the department of preventive medicine at the Vanderbilt University School of Medicine in Nashville, TN, has been consulted by hospitals being sued for MRSA infections, including one involving some 80 patients.

"These were not class actions but individual lawsuits that relate to MRSA," he says. "There are some attorneys who clearly have a profound misunderstanding of what is now the very complex epidemiology of MRSA infections because of the distinction between hospital-associated and community-associated (CA-MRSA.) They have the notion that MRSA had to be acquired in the hospital and if acquired in the hospital, had to be the result of some sort of inadequacy. The very explicit language of the SHEA document has been picked up by plaintiffs attorneys and by [consumer advocates and critics]."

While it sounds rather straightforward to culture patients on admission, Schaffner warns the situation can quickly lead to tough decisions. "If you get a positive, what do you do next? Those solutions vary in degree all the way up to people who think you ought to try and decolonize the patient. Now all of a sudden a patient comes in, they're colonized — they're not ill with MRSA — and somebody in the institution wants to start treating them in some fashion to get rid of the MRSA."

Even if a decision is made to try to decolonize patients reporting to the hospital for other conditions, the overall success of the effort could depend on other less obvious factors. "Can you do that without culturing the [patient's] family when they leave?" he says. "They'll just get recolonized within a week after they go home again. I don't think all those questions have been answered. There are provocative reports increasingly in the literature that suggest some of these [strategies may work], but I don't know that they deal with the new era of community-associated MRSA. I think most of those reflect back to when the only MRSA we were concerned about was the traditional hospital MRSA."

Indeed, clinicians who go to active screening may find a surprising level of otherwise healthy people colonized with strains of both CA-MRSA and MRSA.

"Here in Nashville, our pediatric infectious disease folks went out to a group of pediatric practices and cultured the noses of a several hundred preschoolers — perfectly normal young children," Schaffner says. "You will be shocked to hear that 9% of them were carrying MRSA. The implications of that are that if you culture at the door of our children's hospital, virtually one out of 10 children would have to be put in isolation. I don't know if we can manage that."


  1. Muto CA, Jernigan JA, Ostrowsky BE, et al. Special report: SHEA guideline for preventing nosocomial transmission of multidrug-resistant strains of Staphylococcus aureus and Enterococcus. Infect Control Hosp Epidemiol 2003; 24:362-386.
  2. Centers for Disease Control and Prevention. Healthcare Practices Infection Control Advisory Committee (HICPAC). Draft Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings 2004. Atlanta; 2004. [Unpublished.]
  3. McCaughey B. "The Next Asbestos." New York Law Journal, June 6, 2006.