The Medical Center at the University of Washington is once again facing cases of infections from Legionella bacterium stemming from within the facility.
Legionella bacteria causes Legionnaires’ disease. A severe and sometimes lethal form of pneumonia, the current strain has already led to four infections and two deaths at the hospital’s Cascade Tower.
In the past, the Washington State Department of Labor & Industries investigated employee safety after Legionella bacteria was detected in a cooling tower used to regulate the hospital’s temperature. Cooling towers are commonly linked with the growth of bacteria like Legionella, and need to be inspected periodically to ensure that fill media and heat transfer surfaces are free from biological growth, scale, corrosion, and particulate deposits — which cannot only reduce energy efficiency, but can pose a health risk.
The recent infections at the medical facility are unrelated to the bacteria found in the cooling tower. The current bacterial strain is of a different genomic makeup. The same bacteria from the current infection cases has been found in a sink, an ice machine, and three of the center’s heater-cooler machines, which are used to manage blood temperature during organ transplant.
The original source of the Legionella has yet to be identified. Equipment that has been infected with the bacteria was taken out of service and cleaned, and the water system underwent a hyper-chlorination process. This process involves adding a chlorine solution to the system at levels toxic enough to kill the bacteria. Then, the water is cleared until chlorine is returned to a level safe for drinking. In the meantime, water use has been severely restricted and bottles of water have been provided for drinking. In addition, filters designed to remove the bacteria are being installed in showers and sinks.
Other buildings within the medical center have been tested and returned negative results for the presence of Legionella. Students have been reassured that they are not in danger, as the college’s main campus is on an entirely separate water system. Transmission of the disease from person-to-person is extremely rare, and if the disease does develop, it can be treated with antibiotics. The disease mainly presents a threat to those who are already ill.