Whole-blood interferon-gamma release assay for baseline tuberculosis screening of healthcare workers at a Swiss university hospital.

family members or visitors. No correlation was found between isolates recovered from routine surveillance cultures done for patients and isolates found to be colonizing or contaminating patients' family members or visitors. The duration of family visits in our ICU (3 or more hours per day) is no shorter than the visiting times reported in other countries.'' In addition, 18 of 33 patients had a length of stay of 15 days or more. Thus, limited exposure time is not a good explanation for the lack of correlation between isolates recovered from patients and isolates recovered from their respective family members and visitors. Hand washing is recommended as the most effective means to prevent transmission by direct contact, because it reduces the concentration of contaminants on the skin. We did detect contamination with A. baumanii on the hands of visitors prior to hand washing at departure, an organism that was also isolated from the patients that they visited. After that, these visitors were monitored for the presence of A. baumanii prior to entry to the ICU and after hand washing; A. baumanii was not isolated again from these individuals. We believe the lack of correlation between the isolates recovered from patients and those recovered from family members may relate to our hand washing policies. Fumagalli et al. have shown that an unrestricted visitation policy, despite imposing a greater microbial burden and greater environmental contamination, does not increase the risk of infectious complications'in cardiac ICU patients. Potential pathogens isolated from patients do not appear to be the same as those carried by their family members and visitors, nor does exposure to these pathogens increase the risk of infection in the ICU if appropriate hand hygiene is enforced.