Hospital Workers May Trigger Dangerous Outbreaks

MONDAY, Oct. 19 (HealthDay News) -- Hospital workers who see many patients may play a disproportionate role in spreading dangerous hospital-acquired infections, a new study finds.

These so-called peripatetic workers, such as radiologists or physical therapists, visit many patients in the course of a day, said Laura Temime, a researcher at the Conservatoire National des Arts et Metiers in Paris, and lead author of a study published online Oct. 19 in the Proceedings of the National Academy of Sciences.

"Although to my knowledge, an increased super-spreading potential of 'peripatetic' health-care workers has never really been formalized as a major hypothesis, there have been several reports of nosocomial outbreaks that have been traced back to such 'peripatetic' health-care workers," Temime said.

Her study adds to the evidence, she said. The study used a mathematical model of a hypothetical intensive care unit that was presumed free of the pathogen to see how easily hospital-based infections, such as methicillin-resistant Staphylococcus aureus (MRSA) spread.

Containing these outbreaks is of grave importance, public health officials agreed.

For the study, Temime divided workers into three groups -- a nurse-like group, which made frequent visits to a small number of patients assigned to them; a physician-like group, which made infrequent visits to a larger number of patients, and the peripatetic group, which visits all patients daily, such as physical therapists.

Next, using a complex mathematical model, the researchers assumed how long the patients would stay -- an average of 10 days -- and how much exposure they would have to each of the three categories of workers, plus how compliant the workers were with hand washing.

Then they computed the impact. They found infection rates increased by up to three times more when a peripatetic worker failed to wash his hands, compared to workers in the other groups.

The conclusions sound very logical, said Dr. Zachary Rubin, an epidemiologist at Santa Monica-UCLA Medical Center and Orthopaedic Hospital in Santa Monica. However, he added, "this is a mathematical model, and you have to do studies with human beings to see if the data is still true or not."

Temime said she and her colleagues are doing just that. They are involved in a European project called Mastering Hospital Antimicrobial Resistance (MOSAR), in which data on exposures and bacterial colonization will be collected on patients and health-care workers. "We are planning to use this data to validate our model," Temime said.

For now, many hospitals are stepping up efforts to promote hand washing among employees. Because the peripatetic workers have "major superspreading potential," the study authors recommend individual surveillance of these health-care workers.

Rubin said that hospitalized patients shouldn't be shy about asking the health-care workers who come in contact with them to follow infection control guidelines. Some hospitals have posted signs in patient rooms asking "Did your health-care worker wash his hands?" to make patients more aware of the importance of hand washing, he said.

"If a patient is concerned [about lack of hygiene from a health-care worker], he can always talk to the head nurse or charge nurse," Rubin said, as well as the hospital's patient advocate or his own physician.

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SOURCE: Zachary Rubin, M.D., epidemiologist, Santa Monica-UCLA Medical Center and Orthopaedic Hospital, California, and assistant clinical professor, medicine, division of infectious diseases, David Geffen School of Medicine, UCLA; Laura Temime, Ph.D., researcher, Conservatoire National des Arts et Metiers, Paris, France; Oct. 19, 2009, Proceedinsg of National Academy of Sciences, online