Is Legionella anisa in the hospital water a concern?
Legionella anisa is a fairly common environmental species. In a recent survey we have found that about 20% of hospitals in the US are colonized; the number of reported cases of infection is extremely low. There is a reported outbreak of non-pneumonic legionellosis (“Pontiac Fever”) due to L. anisa occurring in an automobile plant due to contaminated, aerosol generating equipment. There is limited laboratory evidence to suggest that L. anisa may be somewhat less pathogenic that L. pneumophila, at least based on an ability to infect mammalian cells.
The risk of disease after exposure to environmental L. anisa by healthy people, or the general hospital patient population is exceedingly low. It might be advisable, however, to protect highly immunocompromised patients, such as transplant patients, patients on high dose corticosteroids, from exposure.
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