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Fatal legionellosis in patients with malignant hematologic diseases
D Schürmann1, B Ruf, F Pfannkuch
1II Medizinische Klinik, Rudolf-Virchow-Krankenhauses, Berlin, Germany.
Abstract:
Pneumonia was present in 70/157 (44.6%) autopsied patients with malignant hematologic diseases. In 16/70 patients (22.9%), legionellae were found to be the causative agents by screening lung tissue specimens with the direct fluorescent antibody method. In 5/16 patients with Legionella pneumonia, in whom legionellosis had been suspected clinically, the diagnosis had already been established by serology, urinary Legionella antigen detection, and culture. These results provide evidence that legionellosis is an important pneumonia etiology in patients with malignant hematological diseases. Thus, Legionella diagnostics should be applied routinely, and antibiotics effective in the treatment of legionellosis should be added to the usual therapy in patients with etiologically unexplained pneumonias. In view of the common occurrence of relapses of Legionella pneumonia, antibiotic therapy should be continued for an extended period.
Insights
Legionella bacteria cause significant pneumonia in patients with hematologic cancers. Early Legionella diagnostics and targeted antibiotics are crucial for effective treatment and preventing relapses in these vulnerable patients.
Area of Science:
- Medical Microbiology
- Hematology
- Infectious Diseases
Background:
- Malignant hematologic diseases significantly increase pneumonia risk.
- Identifying specific pneumonia etiologies in these patients is challenging but critical.
Purpose of the Study:
- To determine the prevalence and significance of Legionella as a cause of pneumonia in patients with malignant hematologic diseases.
- To evaluate the effectiveness of current diagnostic methods and treatment strategies for Legionella pneumonia in this population.
Main Methods:
- Autopsy lung tissue screening using the direct fluorescent antibody method.
- Clinical suspicion confirmation via serology, urinary antigen detection, and culture.
- Review of patient data for diagnosis and treatment outcomes.
Main Results:
- Pneumonia was identified in 44.6% of autopsied patients with malignant hematologic diseases.
- Legionella species were identified as the causative agent in 22.9% of these pneumonia cases.
- In 31.25% (5/16) of Legionella pneumonia cases, the diagnosis was pre-mortem confirmed by various methods.
Conclusions:
- Legionellosis is a significant and often underdiagnosed cause of pneumonia in immunocompromised patients with hematologic malignancies.
- Routine Legionella diagnostics and prompt initiation of effective antibiotic therapy are essential.
- Extended antibiotic treatment duration is recommended due to the high risk of relapse.