Legionnaires Disease in Immunocompromised Host

Abstract

Legionella bacteria are aerobic, pleomorphic, gram negative bacilli found in fresh water environments and are usually transmitted through inhalation aerosols from contaminated water or soil. Legionnaire's disease is a severe form of pneumonia caused by legionella species and can be community acquired or hospital acquired. The reported incidence of Legionnaires' disease is approximately 1.4-1.8 cases per 100,000 persons and immunocompromised state is a very important risk factor. Some of the other important risk factors include old age, impaired cellular immunity, hematologic malignancies, solid organ transplantation, splenectomy, tumor necrosis factor-alpha inhibitors, chronic respiratory disease, diabetes and end stage renal disease. Legionella pneumophila serotype 1 is the most commonly reported cause of human Legionella infections. The pathogenesis of legionnaire's disease involves invasion of alveolar macrophages and cell mediated immunity is the primary means of immune control. The prevalence of Legionnaires disease has risen possibly from increased awareness and reporting. The symptoms of the disease are nonspecific requiring a high index of suspicion in vulnerable hosts, as effective treatment could be life-saving. Sensitivity of urinary antigen testing is lower in immunocompromised patients because of higher likelihood of infections caused non L. pneumophila species. Extrapulmonary manifestations and higher mortality are particularly more common in immunocompromised patients than in immunocompetent hosts.

Legionella pneumophilapneumonia: A 5‑year retrospective clinical evaluation and commentary

“…In total, 2 patients presented immunosuppression factors (AIDS and systemic lupus erythematosus), and 2 patients had cancer. Of note, as indicated in the literature (32), immunosuppressed patients tend to exhibit an atypical presentation and signs, such as lung cavitations (33)(34)(35)(36).…”

Photocatalytic TiO2-Based Nanostructures as a Promising Material for Diverse Environmental Applications: A Review

“…Salmonella, inducing illnesses such as typhoid fever and salmonellosis [3], and cholera, caused by Vibrio cholera's cholera toxin production [4], are severe diseases. Bacterial pathogens, like Pseudomonas aeruginosa, contribute to conditions like diarrhea and Shanghai fever [5], while Legionella, a primary agent in transmitting Legionnaire's disease [6], can proliferate in water sources.…”