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Lung abscess caused by Legionella species: implication of the immune status of hosts

Hui Yu1, Futoshi Higa, Michio Koide

  • 1Department of Medicine and Therapeutics, Control and Prevention of Infectious Diseases (First Department of Internal Medicine), Faculty of Medicine, University of the Ryukyus, Okinawa, China.

Internal Medicine (Tokyo, Japan)
|December 3, 2009
PubMed

Insights

Legionella lung abscess is rare but can occur in hospital or community-acquired infections. Corticosteroid use and altered neutrophil counts may predispose individuals to this serious Legionella infection.

Area of Science:

  • Infectious Diseases
  • Pulmonology
  • Microbiology

Background:

  • Legionella pneumonia commonly presents as lobar pneumonia.
  • Legionella lung abscess is an uncommon but severe manifestation.
  • Identifying risk factors for Legionella abscess is crucial for patient management.

Purpose of the Study:

  • To identify predisposing factors for Legionella lung abscess.
  • To analyze clinical characteristics and outcomes of Legionella abscess cases.

Main Methods:

  • Systematic review and analysis of 62 case reports on Legionella abscess from existing literature.
  • Categorization of infections into hospital-acquired and community-acquired.
  • Analysis of patient demographics, clinical features, causative Legionella species, treatments, and outcomes.

Main Results:

  • Legionella abscess occurred in both hospital-acquired (45.2%) and community-acquired (45.2%) infections.
  • Mortality rate was 27.4%.
  • Corticosteroid use (69.4%) was common; higher peripheral neutrophil counts and low lymphocyte counts were observed. Abscess formation sometimes occurred during neutropenia recovery.

Conclusions:

  • Corticosteroid treatment, potentially impairing cellular immunity, may predispose to Legionella abscess.
  • Altered neutrophil and lymphocyte counts are associated with Legionella abscess development.
  • Further research into the pathogenesis and prevention of Legionella abscess is warranted.

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