Legionellosis in Massachusetts: Commoner Than We Think! A Community Hospital Experience
The incidence of Legionnaires' disease in the USA has more than doubled from 2000 to 2009. There are currently an estimated 8000-18000 cases annually. These are frequently associated with underlying risk factors and exposure to an environmental source.
Patients of all ages and both genders who were admitted to MetroWest Medical Center, Framingham, MA and Saint Vincent Hospital, Worcester, MA with a confirmed diagnosed of Legionellosis between 1st January 2012 and 31st December 2013 were enrolled.
Of 25 patients with legionellosis, all presented with respiratory symptoms, 14 (56%) also had gastrointestinal complaints and 4 (12%) a change in mental status. There was no geographic clustering of cases (figure) and no common exposure history. Two thirds were male. Nineteen (76%) had at least one risk factor. Fourteen (56%) had a significant smoking history and 4 (16%) chronic lung disease. Other risks factors included cirrhosis, corticosteroid use, tumor necrosis factor inhibitor use and malignancy. The majority of the patients presented during the summer and fall. A urinary legionella antigen test was positive in all patients. Initial laboratory abnormalities included 18 (72%) patients with hyponatremia and 10 (40%) with abnormal liver function tests. All had radiologically confirmed pneumonia; 7 (28%) multilobar and 5 (20%) with pleural effusion. No patient had Legionella pneumophilaisolated bacteriologically. Eight (32%) were admitted to ICU and 6 (24%) required intubation. All patients received levofloxacin or azithromycin for treatment. Infection was fatal in 4 (12%).
Current guidelines recommend screening for L. pneumophila infection in cases of severe pneumonia, given testing is relatively inexpensive, more widespread screening may help early de-escalation and provision of targeted antimicrobial therapy.
Figure. Map of number of Legionella pneumonia cases by zip code.
T. Treadwell, None
R. Maude, None
G. Abraham, None