December 1999
SAN FRANCISCO - Although the isolation guidelines from the Centers for Disease Control and Prevention specify that contact precautions be used "for patients known or suspected to be colonized or infected with epidemiologically important microorganisms," effective control of such pathogens has not been reported in all hospitals.
"Because nothing comes from nothing, it is important to know who has these microorganisms. These patients represent the reservoir for further spread," said Barry M. Farr, MD, director of epidemiology at the University of Virginia School of Medicine in Charlottesville, Va. "From this reservoir, though, the infectious process can be halted."
An ongoing study in 40 hospitals assessing antibiotic resistance in intensive-care areas identified the following four risk factors: volume of antimicrobial use, noncompliance with infection-control guidelines, spread from neighboring facilities, and location within the hospital.
"The first two risk factors are probably the most important," Farr noted.
![[bar]](/art/gradred.gif){kind=small}
Simple steps can have a profound effect. For example, "some health care facilities have not caught on that alcohol-based products containing emollients are kinder and gentler to hands, and provide very good cleansing and de-germing of hands coming out of rooms that contain antibiotic-resistant pathogens," said Farr, who spoke here at the 39th Interscience Conference on Antimicrobial Agents and Chemotherapy.
Likewise, some facilities "may not be providing a lotion to preserve the integrity of the healthcare worker's hand, which I consider a vital aspect of infection control. If the hand becomes a ragged pair of claws, then those hands are an infection-control nightmare. Organisms may be multiplying within the cracks and crevices, and be a bigger risk to patients. So it's not just to wash your hands over and over, it is to care and protect your hands."
Instruments and equipment moved from patient room to patient room also need to be properly disinfected. "Surveillance means looking to see what is going on - knowing if and when the rate of something bad goes up that requires action," Farr said. One study found that effective infection-control programs could reduce the rate of nosocomial infections by 32%. "This study concluded that intensive surveillance was a key component of effective hospital infection-control programs," he said. In fact, "there's an old saying in epidemiology that he who does not believe in doing effective surveillance, enjoys working in the dark and probably shouldn't pilot his own plane."
Another old epidemiologic saying is that he who ignores the iceberg phenomenon (with the vast majority of the methicillin-resistant Staphylococcus aureus [MRSA] and vancomycin-resistant Enterococcus [VRE] spread probably coming from the invisible part) may encounter problems of Titanic proportions.
"The organisms that we're looking for are invisible, unless one uses special tests. Cultures are usually necessary to find them," Farr emphasized.
Certain investigators have reported that MRSA is not well controlled with isolation. For instance, Thompson, et al, reported failure to control an epidemic spread of a single strain of MRSA from 1978 through 1980. "Some have argued that such epidemic strains have special virulence properties favoring spread and clinical infections, and that they simply can't be controlled," Farr said. However, when Thompson initiated active surveillance cultures and contact/droplet isolation, "the previously uncontrollable became controllable," Farr continued. "The endemic strain was eradicated from the hospital over the next 18 months by using this approach."
A similar approach limited an MRSA outbreak in a neonatal intensive care unit (NICU) to colonization of 18 (3%) and infection of four of 597 neonates during 10.5 months. "Contact/droplet precautions decreased the risk of transmission by 15.6-fold as compared with standard precautions," Farr reported. These findings may be important because "five of seven recent prognostic studies have found significantly higher mortality with MRSA than with methicillin-susceptible S. aureus bacteremias."
Active surveillance is also extremely cost-effective. The estimated cost of 4,169 active surveillance cultures and 691 days of isolation for control of the outbreak in the NICU was $48,000 to $68,000, compared with $263,000 to $2,495,000 for the 75 MRSA blood stream infections and 14 deaths that occurred in another NICU outbreak that was not rapidly controlled. "This illustrates the importance of prompt control," Farr said. "An epidemiologist can't conclude that a rate is good or bad without controls. Likewise, a prudent hospital administrator should not decide if the cost of intervening is too high without first knowing the cost of not intervening."
One strategy to dramatically reduce the cost of infection control is to implement widespread culturing, set up large cohorts and have health care workers continuously wear the barriers. "There would be no reason for workers to take off their gowns every time they enter or exit a patient room because everyone in the cohort would have VRE, for instance," Farr said.
Overall, "if we all doubled or tripled the cost of our infection-control effort to contain the problem of antibiotic resistance, we would still be far more cost effective than most well-accepted therapeutic and preventive interventions," Farr concluded. Morbidity and mortality rates could also be reduced.
| Intensive Care Unit Risk Factors |
|---|
|
An ongoing study in 40 hospitals assessing antibiotic resistance in intensive-care areas identified the following four risk factors.
|
For more information:
- Farr BM. Efficacy and impact of isolation and surveillance. Session 140.K. Presented at the 39th Interscience Conference on Antimicrobial Agents and Chemotherapy. September 26-29. San Francisco.
You can
express your views on this article, or other relevant themes, in the
Infectious Diseases in Children
Specialty Forums.