Screen and isolate or standard precautions?

The challenge to control drug-resistant bugs

Rather than special measures such as screening and isolating patients, infection control professionals should focus their limited resources on improving compliance with standard precautions to battle multidrug-resistant organisms such as vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA), a veteran nurse educator recently argued.

"There is evidence that standard precautions, when practiced consistently and correctly, can prevent transmission of VRE, MRSA and other organisms," said Marguerite Jackson, RN, PhD, CIC, FAAN, director of education, development, and research at University of California in San Diego Health Care.

On the contrary, another infection control expert argued, the only way to prevent nosocomial spread of resistant pathogens is to identify the colonized patient reservoir and place them in contact isolation (i.e., gowns for patient contact). "Nosocomial spread accounts for almost all of the patients with these pathogens," said Barry Farr, MD, epidemiologist at the University of Virginia (UVA) Hospital in Charlottesville. "The reservoir for spread is usually colonized patients. Actively identifying this reservoir for spread and implementing contact precautions offers more effective control than do standard precautions."

Such were the positions taken as two well-known members of the infection control community squared off in an interesting, educational debate on multidrug-resistant pathogens recently in Nashville, TN, at the annual conference of the Association for Professionals in Infection Control and Epidemiology (APIC).

Jackson is a past president of APIC, and Farr is the current president of the Society for Healthcare Epidemiology of America (SHEA). In general terms, the respective membership of each group is primarily composed of doctors (SHEA) and nurses (APIC). With that professional difference as a subtext, Jackson pointed a finger at physicians who inappropriately prescribe antibiotics.

"Why is there so much emphasis on interrupting transmission rather than other strategies?" Jackson said. "One [reason] is because it is very difficult to control antimicrobial prescribing behavior of physicians. It is almost impossible to make those people behave! There is the belief that you can make the nurses and the other folks behave better by telling them what to do [rather] than by making doctors do what they ought to do about antibiotics. It’s a whole lot easier to write rules and to make the nurses behave because the health care organization can control the paychecks of the nurses [rather] than the physicians, who are free agents. That is a perception. I haven’t had a double-blind clinical trial evaluate that, but I think that perception is probably shared by many of you."

Rather than attempting to identify patients colonized with VRE and MRSA and place them in contact isolation, Jackson argued for strict adherence to standard precautions with all patients. Standard precautions (formerly called universal precautions) primarily emphasize hand hygiene and appropriate glove use with all patients to prevent transmission of recognized and unrecognized sources of infection.

"The principle on which standard precautions is based theoretically makes a great deal of sense," she said. "However, the second part of this principle is that consistent observance offers the greatest potential for decreasing transmission of infectious agents. . . . The key to success here is health care worker compliance."

There is substantial evidence that consistent adherence to standard precautions is poor, she said. "The increasingly serious international nurses shortage adversely affects correct and consistent compliance with standard precautions and other transmission precautions," she added.

By that same token, trying to adopt more rigorous measures, such as screening, isolating, and gowning for colonized patients, is likely to fall afoul of poor compliance. "The busier the nurses are, the less they wash their hands," Jackson said. "If you’re a nurse, it does not take rocket science to figure that out. That is what happens. When nurses are busy, they wash their hands and comply with other recommendations less frequently. If the compliance is poor for hand washing, would compliance with other infection control recommendations — be it standard precautions, contact precautions, or whatever — [be any better]?"

Rather than emphasize transmission-driven guidelines for individual pathogens, Jackson said she favors marshalling efforts to improve compliance with standard precautions. Jackson is serving as a consultant to the Centers for Disease Control and Prevention’s Healthcare Infection Control Practices Advisory Committee (HICPAC), which is in the process of updating patient isolation guidelines. Those guidelines are being finalized, but one draft discussed at a recent HICPAC meeting states that that "in acute care, an overemphasis on additional transmission-based precautions . . . can diminish the adherence to standard precautions." (See Hospital Infection Control, April 2002, under archives at www.HIConline.com.)

While both speakers cited a wealth of research to support the efficacy of their positions, Farr added an ethical appeal. "We take TB seriously, actively looking for contagious patients and using transmission-based precautions that work much better than standard precautions for this," he said. "By contrast, we don’t usually actively look for antibiotic-resistant infections even though they cause far more deaths — 130,000 to 150,000 over the past decade, with MRSA and VRE undoubtedly contributing heavily to this toll. Is it OK to just look the other way while hospital contagion claims thousands of lives?"

MRSA accounted for one-third of nosocomial S. aureus infections in Denmark before health care professionals started taking effective action, he noted. "They controlled it over the next decade and have kept it less than 1% now for a quarter of a century using active surveillance cultures and contact precautions the whole time."

Infection control programs in the United States were born in the early 1970s when penicillin-resistant S. aureus exploded through the health care system, he reminded. The programs were formed because "we might not always be able to cure antibiotic-resistant infections so we should figure a way of preventing them," Farr said. "We have failed to control nosocomial MRSA infections, which almost doubled in rate between 1989 and 1999. We are clearly failing to control nosocomial VRE infections as well."

Patients with positive clinical cultures for VRE or MRSA represent the tip of a figurative iceberg, Farr said. They are the reservoir for spread to other patients because they go unrecognized and unisolated without active surveillance cultures. Health care workers then spread the pathogens on transiently colonized hands, clothes, and equipment.

"[Research] has shown that when we examine a patient with MRSA or VRE, we frequently end up with it on our clothes if we’re not wearing a gown," said. "Two-thirds of the time, gown, gloves, and/or stethoscope were contaminated whether the patient was infected or colonized."

Detractors of the screening/isolation approach often cite the expense of such measures, but Farr argues that it is cheaper than treating infected patients. "It is cheaper to use active surveillance cultures and contact precautions to control MRSA and VRE than it is to use standard precautions and just let it spread," he said.