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Severe pneumonia due to concurrent Legionella pneumophila and Acinetobacter baumannii infections: a case report
Xiaoming Yang1, Zhongda Liu1, Xiaojing Liu1
1Department of Respiratory and Critical Care Medicine, Lishui Hospital of Traditional Chinese Medicine Affiliated to Zhejiang University of Traditional Chinese Medicine, No. 800 Zhongshan Road, Liandu District, Lishui, Zhejiang, 323000, China.
Background:
Legionella pneumophila is an uncommon pathogen causing community-acquired atypical pneumonia. Acinetobacter baumannii is a major pathogen responsible for hospital-acquired pneumonia, but it rarely causes serious infections in a community setting. Without prompt and appropriate treatments, infection from either of these two pathogens can cause a high mortality rate. Concurrent infection from both L. pneumophila and A. baumannii can cause serious outcomes, but it has rarely been reported previously.
Case Presentation:
A 45-year-old male presented to our hospital with a productive cough and fever after staying in a local hotel. His chest computed tomography (CT) scan showed bilateral lower-lobe infiltration and left pleural effusion. Empirical antibiotics, including piperacillin-tazobactam, levofloxacin, meropenem, and doxycycline, were administered to him to treat community-acquired pneumonia. However, his condition deteriorated very rapidly, and he required endotracheal intubation and mechanical ventilation for respiratory support. Finally, metagenomic next-generation sequencing (mNGS) of his bronchoalveolar lavage fluid identified L. pneumophila and A. baumannii. The sputum culture demonstrated multidrug-resistant A. baumannii. He was diagnosed with pneumonia by concurrent infections from both L. pneumophila and A. baumannii. After careful consideration of the antibiotic susceptibility results and the antibacterial mechanism of each antibiotic, we switched the antibiotics to omadacycline and cefoperazone/sulbactam. His clinical symptoms gradually subsided. The repeat chest CT image showed no infiltration or pleural effusion.
Conclusions:
Community-acquired pneumonia can be caused by concurrent infections of both L. pneumophila and A. baumannii. Close clinical monitoring, early pathogen detection and antibiotic susceptability tests, and appropriate antibiotic regimen adjustments should be applied to these patients who failed initial antibiotic treatments.
Insights
Concurrent Legionella pneumophila and Acinetobacter baumannii infections can cause severe community-acquired pneumonia. Early detection and tailored antibiotic treatment are crucial for patient recovery.
Area of Science:
- Infectious Diseases
- Microbiology
- Pulmonology
Background:
- Legionella pneumophila typically causes community-acquired pneumonia, while Acinetobacter baumannii is associated with hospital-acquired infections.
- Concurrent infections with both pathogens are rare but can lead to severe outcomes and high mortality.
- Prompt and accurate diagnosis and treatment are critical for managing these challenging infections.
Purpose of the Study:
- To report a rare case of community-acquired pneumonia caused by concurrent Legionella pneumophila and Acinetobacter baumannii infections.
- To highlight the diagnostic challenges and treatment strategies for such dual infections.
Main Methods:
- A patient with severe community-acquired pneumonia was treated with empirical antibiotics.
- Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid identified both L. pneumophila and multidrug-resistant A. baumannii.
- Antibiotic regimen was adjusted based on pathogen identification and susceptibility testing.
Main Results:
- The patient's condition rapidly deteriorated despite initial empirical treatment.
- mNGS successfully identified concurrent L. pneumophila and A. baumannii infections.
- Switching to omadacycline and cefoperazone/sulbactam led to clinical improvement and resolution of pneumonia.
Conclusions:
- Community-acquired pneumonia can result from concurrent L. pneumophila and A. baumannii infections.
- Close monitoring, early pathogen detection, and susceptibility testing are essential.
- Tailoring antibiotic regimens based on diagnostic results improves patient outcomes in cases of treatment failure.
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