Related Experiment Videos
[Clinical and diagnostic characteristics of Legionella pneumonia]
K Yamaguchi1, K Tateda, Y Ishii
1Department of Microbiology, Toho University School of Medicine.
Abstract:
We have characterized clinical and diagnostic features in 18 cases of Legionella pneumonia. Age average of patients was 62.0 years old (male:female = 14:4) and underlying diseases were observed in 12 patients. Legionella pneumonia were diagnosed in 3, 5, 8 and 9 cases by culture, serum antibody measurement, urinary antigen detection and PCR, respectively. Sixteen cases were caused by L. pneumophila, while the other 2 cases were L. bozemanii pneumonia and L. pneumophila or L. dumoffii pneumonia. Chest X-rays of those patients showed multiple pneumonia shadows in 14 cases, alveolar shadows in 10 cases, pleural effusion in 5 cases. Blood-gas analysis on admission indicated hypoxemia in all cases with abnormal A-a DO2. Laboratory findings showed abnormal data in WBC, CRP, LDH, CPK and liver function tests (ex. GOT, GPT) in most cases. Serum antibody testing showed positive by 5 weeks after onset of pneumonia, but 10 cases of Legionella pneumonia diagnosed by other techniques were judged to be negative. In urinary antigen detection test, 6 and 2 cases showed positive 1 and 4 weeks after onset of pneumonia, respectively. Macrolide antibiotics were administered in all cases during the episode, but delay of macrolide administration was observed in 3 of 4 cases of dead outcome. Serum antibody measurement, urinary antigen detection and PCR, in addition to culture to bacteria, may be required for exact diagnosis of Legionella infection.
Insights
Diagnosing Legionella pneumonia requires multiple methods beyond bacterial culture. Combining serum antibody, urinary antigen, and PCR tests improves accuracy, especially when macrolide antibiotic treatment is delayed.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Pulmonology
Context:
- Legionella pneumonia presents diverse clinical and diagnostic challenges.
- Accurate and timely diagnosis is crucial for effective treatment and patient outcomes.
Purpose:
- To characterize clinical and diagnostic features of Legionella pneumonia in 18 cases.
- To evaluate the effectiveness of different diagnostic methods for Legionella infection.
Summary:
- This study analyzed 18 Legionella pneumonia cases, noting a median age of 62 and frequent underlying conditions.
- Diagnostic methods included culture, serum antibody, urinary antigen detection, and PCR, with varying sensitivities.
- Chest X-rays revealed common findings like multiple pneumonia shadows and hypoxemia.
- Laboratory tests showed abnormalities in WBC, CRP, LDH, CPK, and liver function.
- Serum antibody tests were positive late (5 weeks), while urinary antigen and PCR offered earlier detection.
- Delayed macrolide administration correlated with fatal outcomes.
Impact:
- Highlights the limitations of individual diagnostic tests for Legionella.
- Emphasizes the need for a multi-test diagnostic approach for accurate Legionella pneumonia diagnosis.
- Informs clinical practice regarding timely antibiotic administration for improved survival rates.