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One of the major reasons many U.S. hospitals have failed to stem the tide of antibiotic-resistant pathogens is the failure to invest the time, effort, and expense in doing active surveillance cultures to detect colonized and infected patients, a leading epidemiologist argues.
"The Centers for Disease Control and Prevention (CDC) estimates right now that there about 13,000 Americans dying of antibiotic-resistance infections each year," says Barry Farr, MD, epidemiologist at the University of Virginia (UVA) Hospital in Charlottesville. "Most of [those infections were] acquired by spread in health care facilities. That is going to keep getting worse if we don’t do something."
Rather than merely isolating patients with known infections, Farr advocates more aggressively screening patients for nosocomial pathogens, such as Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Then those who are colonized or infected can be placed in contact isolation rather than serving as an undetected reservoir to spread the pathogens to other patients, he argues.
"Active surveillance cultures [are needed] to detect the reservoir for spread," he tells Hospital Infection Control. "If you have a legionella outbreak, wouldn’t you want to know where it is coming from? We screen at various times. We do some screening on admission, and we do some screening of people who are staying in the hospital in high-risk wards and if they are on antibiotics."
In arguing his case in a recently published article, Farr cites surveys, which underscore that few hospitals are doing such surveillance.1-3 "The surveys that have been done suggest that only a small minority are actually doing this and doing it in a meaningful manner," he says.
Infection control professionals that do not conduct active screening may conclude that their isolation measures are not working, but it is really an undetected reservoir of patients that is fueling the infection rates, Farr says. Recent studies indicate that 95% of the VRE reservoir and at least 66% of the MRSA reservoir go undetected in the absence of active surveillance cultures.4,5 While he cites the success of countries such as Denmark that have used the practice to virtually eliminate MRSA, Farr became convinced of the need for active surveillance cultures based on the situation at his own hospital.
"When MRSA arrived at UVA, it kept getting worse and worse," he says. "In 1977, there was none; in 1979, there was quite a bit. In 1980, half of all the surgical site infections in the hospital and 40% of all the Staph aureus bloodstream infections were one strain of MRSA that was spreading all over the hospital. That’s about as bad — in 1980 — as the national data are now for the United States. We were leading the country."
The outbreak was then completely controlled, including eradicating the epidemic MRSA strain from the hospital, by using active surveillance cultures to identify colonized patients and place them in contact isolation. "That’s why our rates are better," he says. "It’s not because it couldn’t happen here. It had already happened here."
Several studies indicate that the costs of MRSA and VRE infections exceed those of prevention, Farr emphasizes.6-10 With their screening program leading to prompt identification and isolation of patients, thus preventing subsequent transmission to other patients by unrecognized source patients, Farr and colleagues have successfully staved off budget cutters by showing cost-savings due to prevented bloodstream infections (BSI). The hospital is saving between $891,000 and $2.8 million annually by preventing costly BSI infections due to MRSA and VRE, Farr notes. (See HIC May 2001 under archives at www.HIConline.com.)
"To say that we can’t afford to do the right thing, doesn’t convince me," he says. "The infections cost a lot in those hospitals that are not trying to prevent them."
Whereas countries such as Denmark can use older, less-expensive antibiotics to fight infections, the spiraling antibiotic-resistant problem in the United States has forced the development of new more expensive drugs such as linezolid and quinupristin/dalfopristin. While such new weapons are welcome, shadows of emerging resistance already have been cast for both VRE and MRSA.
"An ounce of prevention is sometimes better than a pound a cure, and that is all we are saying. Infection control was started three decades ago to deal with [antibiotic resistance]. If we start now, we’ve got some work to do. But if we could get through it, we can succeed if we want to. Or we can just let it go. That is an open question," he says.
To generate more data on the practice, Farr is participating in a network of hospitals in Virginia and North Carolina that are conducting active surveillance cultures.
It appears such data will be needed to spur a national recommendation for active surveillance cultures from the CDC, which currently leaves the decision to the local level. Yet in a somewhat contradictory gesture, the CDC lauded the effort of ICPs and colleagues in a tri-state Midwest region called the Siouxland Health District after they used surveillance cultures and other methods to eradicate VRE. (See Hospital Infection Control September 1999, under archives at www.HIConline.com.)
Though noting that development of a stronger, national recommendation would have to be made by top CDC officials with the consultation of the Healthcare Infection Control Practices Advisory Committee (HICPAC), one CDC epidemiologist says the practice shows promise.
"Absolutely," says William Jarvis, MD, associate director for program development at the CDC division of healthcare quality promotion. "I think both what Barry [Farr] has shown at the University of Virginia and what we showed at Siouxland is that if you actively identify these patients who are infected or colonized with these organisms, appropriately put barriers between those patients and other patients, and improve hand washing, this — even in the absence of antimicrobial controls — can be an effective way of reducing transmission."
Still, even then it should be left to local ICPs and epidemiologists to determine the screening needs and abilities of their own programs, says William Scheckler, MD, a member of the HICPAC committee and hospital epidemiologist at St. Mary’s Hospital in Madison, WI. "Although we have seen an increase in both community-acquired and nosocomial MRSA infections in our hospital, we are still nowhere near the level that some places are," he says. "When we identify infections in patients, we have a protocol for isolating them and a protocol for recognizing the fact that they have had an infection should they be readmitted. That works pretty well. The VRE experience we have is much, much lower than that and is relatively infrequent. The cost of [active surveillance], processing all those cultures, would be fairly substantial. Most people run up against the idea that the cost benefit doesn’t seem to be there."
Still, hospitals dealing with continuing antibiotic resistant infections may want to consider the method, which they currently are free to do under the CDC practice of leaving those decisions to the local level, he notes. "I think [that approach] makes sense, but the local people have to look at their experience, and as the numbers get higher, they have to be more vigilant," Scheckler says.
1. Farr BM, Salgado CD, Karchmer TB, et al. Can antibiotic-resistant nosocomial infections be controlled? Lancet Infect Dis 2001; 1:38-45.
2. Stosor V, Peterson L, Postelnick M, Noskin G. Enterococcus faecium bacteremia: Does vancomycin resistance make a difference? Arch Intern Med 1998; 158: 522-527.
3. Salgado C, Sherertz R, Karchmer T, et al. Public health initiative to control MRSA and VRE in Virginia and North Carolina. Abstracts of the 11th Annual Meeting of the Society for Healthcare Epidemiology of America. Toronto; 2001. (Abstract 164)
4. Ostrowsky B, Steinberg J, Farr B, et al. Reality check: Should we try to detect and isolate vancomycin-resistant enterococci patients? Infect Control Hosp Epidemiol 2001; 22:116-119.
5. Calfee DP, Giannetta E, Farr BM. Effective control of VRE colonization Using CDC recommendations for detection and isolation. Abstracts of the 38th Annual Meeting of the Infectious Diseases Society of America. New Orleans; 2000. (Abstract 21)
6. Jernigan JA, Clemence MA, Stott GA, et al. Control of methicillin resistant Staphylococcus aureus at a university hospital: One decade later. Infect Control Hosp Epidemiol 1995; 16:686-696.
7. Chaix C, Durand-Zaleski I, Alberti C, Brun-Buisson C. Control of endemic methicillin-resistant Staphylococcus aureus: a cost benefit analysis in an intensive care unit. JAMA 1999; 282:1,745-1,751.
8. Muto CA, Cage EG, Durbin LJ, et al. Cost effectiveness of perirectal surveillance cultures for controlling vancomycin-resistant Enterococcus. Abstracts of the 9th Annual Meeting of the Society for Healthcare Epidemiology of America. San Francisco; 1999. (Abstract 74)
9. Papia G, Louie M, Tralla A, et al. Screening high risk patients for methicillin resistant Staphylococcus aureus on admission to the hospital: Is it cost effective? Infect Control Hosp Epidemiol 1999; 20:473-477.
10. Montecalvo M, Ulman J, Petrullo C, et al. The cost benefit of enhanced infection control strategies to prevent transmission of vancomycin resistant Enterococcus. Abstracts of the 37th Interscience Conference on Antimicrobial Agents and Chemotherapy. Toronto; 1997. (Abstract J84).